JP2013250413A - Optical sheet and production method of the same, el element using optical sheet, and illumination device having the el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sheet having a good transfer rate and appearance even when the sheet has a composite feature of a complicated and fine surface feature and a flat surface feature, when a lens sheet having a concavo-convex structure on a surface thereof is formed by transferring by using a mold.SOLUTION: A lens layer 14 constituting an optical sheet 3 comprises an actinic ray-curable resin with addition of spherical light-transmitting particles. The lens layer is configured in such a manner that: the proportion of the spherical light-transmitting particles in the lens layer is from 0.5 to 40% by volume; an average particle diameter r of the spherical light-transmitting particles satisfies 0.5 μm≤r≤10 μm; maximum height roughness Rz of the concavo-convex structure surface satisfies 30 μm≤Rz≤100 μm; a skewness Rsk of the concavo-convex structure surface satisfies -1.5≤Rsk≤1.5, and the average particle diameter r of the spherical light-transmitting particles and the maximum height roughness Rz have a relationship of r/Rz≤0.1.

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 electric decoration, a light source for signage, and the like, a display device using the EL element, a display device, a liquid crystal display device, etc. The present invention relates to an optical sheet or a film used for the above (referred to as a sheet including both unless otherwise specified), a method for producing the optical sheet, an EL element using the optical sheet, and a lighting device including the same.

  In general, there are EL elements as light sources used for flat panel displays, liquid crystal backlights, illumination light sources, electrical decorations, sign light sources, etc., and various display devices, display devices, liquid crystal display devices, etc. using EL elements. However, these illuminating devices are provided with an optical sheet for diffusing or condensing light emitted from the light source. This optical sheet is produced by providing a specific translucent uneven pattern (lens pattern) on a translucent substrate.

  In order to produce such a translucent uneven pattern, a cylinder or plate mold is patterned by engraving or corrosion represented by a lathe cutting method to form a mold, and this mold pattern A method is used in which a sheet is transferred onto a surface of a light-transmitting substrate, or a sheet having a pattern transferred from a mold onto the substrate is re-transferred to the light-transmitting substrate. Furthermore, the manufacturing method of providing an uneven | corrugated pattern by spreading fine particles on the surface of a translucent base material is used (refer patent document 1).

Japanese Patent Laid-Open No. 8-211205

  Conventionally, in the manufacturing method of this type of optical sheet, in the method using the mold described above, the optical characteristics in the horizontal and vertical directions are adjusted in the display device, and the light extraction efficiency is improved and the surface in the lighting device. In order to improve the scratch resistance performance and reduce costs by reducing the amount of resin used in transfer using an active energy ray curable resin, the mold shape has become more complex and finer. Yes.

  However, when an optical sheet is manufactured by such a manufacturing method, the surface quality including rust may be deteriorated at the stage of imparting an uneven pattern shape to the surface of the mold using a technique such as cutting or corrosion. is there. Then, due to the deterioration of the surface quality of the mold, when releasing the concavo-convex pattern product from the mold at the time of transfer, problems such as poor plate separation and poor moldability arise.

  In addition, a method of adding a release agent or the like to the resin used at the time of molding has been proposed in order to suppress the deterioration of plate separation, but in that case, the surface shape of a pattern-shaped product having a substantially flat portion Since the part has high releasability from the mold, a phenomenon such as delamination that occurs before the molding resin is cured occurs, resulting in a problem that the appearance of the product is poor.

  The present invention has been made in view of such a situation, and when a complex and fine surface shape or a flat surface shape is transfer-molded or a surface shape in which these are combined is transfer-molded, a transfer rate is improved. Another object of the present invention is to provide an optical sheet having a good appearance shape and capable of adjusting the separation of the plate, a method for producing the optical sheet, an EL element using the optical sheet, and a lighting device including the same.

  An optical sheet according to claim 1 of the present invention is formed by laminating a lens layer made of a translucent resin containing spherical translucent particles on at least one surface of a translucent base material. In the optical sheet having a concavo-convex structure on the surface opposite to the translucent substrate, the translucent resin contains an active energy ray curable resin, and the lens layer in the lens layer The ratio of the spherical translucent particles to the total volume is 0.5 to 40 in volume ratio, the average particle size r of the spherical translucent particles is 0.5 μm ≦ r ≦ 10 μm, and the concavo-convex structure surface The maximum height roughness Rz is 30 μm ≦ Rz ≦ 100 μm, the range of the skewness Rsk of the roughness curve of the concavo-convex structure surface is −1.5 ≦ Rsk ≦ 1.5, and the spherical transparent The relationship between the average particle diameter r of the light particles and the maximum height roughness Rz is as follows: It is characterized in that it is /Rz≦0.1.

  The optical sheet according to claim 2 is such that the difference in refractive index between the spherical translucent particles and the translucent resin is 0.001 or less.

  The optical sheet according to claim 3 is such that the difference in refractive index between the spherical translucent particles and the translucent resin is 0.05 or more.

  The optical sheet according to claim 4 is the optical sheet according to any one of claims 1 to 3, and has at least an adhesive layer formed of a heat-fusible adhesive or a pressure-sensitive adhesive, The adhesive layer, the translucent base material, and the lens layer are laminated in this order.

  The method for producing an optical sheet according to claim 5 includes: a translucent resin forming step of forming the translucent resin containing the spherical translucent particles on at least one surface of the translucent substrate; Then, after this translucent resin forming step, using the plate having an uneven shape, the uneven surface of the plate is pressed against the outer surface of the translucent resin, and the uneven shape of the plate is applied to the translucent resin. And a resin curing step of curing the active energy ray-curable resin by irradiating the translucent resin with active energy rays after shaping.

  The method for producing an optical sheet according to claim 6 is the method for producing an optical sheet according to claim 5, wherein the plate is formed of a cylindrical plate, and the cylindrical plate is transferred to the translucent plate by a pressure-bonding roll. The uneven shape of the plate is shaped into a translucent resin by being pressed against the resin.

  The EL element according to claim 7 is obtained by laminating the optical sheet according to claims 1 to 4 on the outermost surface of the light emission side of the EL panel in which the light emitting structure is disposed on the first transparent substrate. is there.

  The lighting device according to claim 8 uses the EL element according to claim 7 as issuing means.

  The optical sheet according to the present invention is obtained by adding spherical translucent particles capable of adjusting the curing shrinkage rate and releasability to the active energy ray-curable resin that is a constituent material of the lens layer in advance, so that the lens layer is formed into a cylinder plate. When the resin is pressed and cured to form, the delamination phenomenon in which the molding resin separates from the plate before curing during curing shrinkage is prevented, and the resin is not taken off. For this reason, an optical sheet having a good transfer rate and high molding stability can be obtained.

  According to the present invention of claim 1, spherical translucent particles having an average particle diameter r of 0.5 to 10 μm are blended so that the volume ratio in the lens layer is 0.5 to 40, and The shape of the concavo-convex structure surface is such that the maximum height roughness Rz is 30 to 100 μm, the skewness Rsk of the roughness curve is −1.5 to 1.5, and the relationship between the average particle diameter r and the maximum height roughness Rz is r / By satisfying Rz ≦ 0.1, an optical sheet having a good transfer rate at the time of molding the lens layer and high molding stability can be obtained.

  According to the second aspect of the present invention, reflection and refraction by the spherical translucent particles do not substantially occur by setting the difference in refractive index between the spherical translucent particles and the translucent resin to 0.001 or less. Thus, an optical sheet that does not produce a scattering effect in the lens layer can be obtained. By not causing the scattering effect in the lens layer, it is possible to prevent the effect of the lens shape on the surface of the lens layer from being lowered.

  According to the third aspect of the present invention, the difference in refractive index between the spherical translucent particles and the translucent resin is set to 0.05 or more so that reflection and refraction by the spherical translucent particles are reflected in the lens layer. An optical sheet having a scattering effect and a high diffusion effect is obtained.

  According to the fourth aspect of the present invention, an optical sheet is formed on an EL panel or the like by laminating an adhesive layer, a translucent base material, and a lens layer formed in this order by a heat-fusible adhesive or a pressure-sensitive adhesive. It can be easily attached to a flat adherend.

  According to the present invention of Claims 5 and 6, a plate having an uneven shape after forming the translucent resin containing the spherical translucent particles on at least one surface of the translucent substrate. The translucent resin containing the spherical translucent particles is pressed into a plate, and after the shape of the plate is formed on the plate, the active energy ray is irradiated to form the active energy ray-curable resin. By curing, the delamination phenomenon in which the molding resin separates from the plate before curing is prevented, and the resin removal phenomenon is less likely to occur. For this reason, it is possible to produce an optical sheet having a good transfer rate and high molding stability. According to the present invention of claim 6, in particular, a cylindrical plate is used, and the cylindrical plate is pressed against the translucent resin with a pressing roll to mold the uneven shape of the plate into the translucent resin. As a result, efficient production can be achieved.

  According to the seventh aspect of the present invention, the optical sheet according to any one of the first to fourth aspects is laminated on the outermost surface on the light emission side of an EL panel in which a light emitting structure is disposed on a first transparent substrate. Thus, there can be obtained an EL element free from variations in products and free from in-plane unevenness.

  According to the eighth aspect of the present invention, by using the EL element according to the seventh aspect as a light emitting means, a lighting device having a stable quality can be obtained.

It is sectional drawing which shows schematic structure of EL illumination element containing the optical sheet by 1st embodiment of this invention. It is a perspective view of the optical sheet shown in FIG. 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.

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

  1 to 4 are views showing an optical sheet according to the first embodiment of the present invention, a manufacturing method thereof, and an EL illumination element (EL element) including the optical sheet. The EL illumination element is provided in, for example, an illumination device including various display devices such as a liquid crystal display device disposed as a light emitting means on the back surface of an image display device such as an EL illumination device, a display device, or a liquid crystal device. used.

  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 configurations can be adopted for this. 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 is transmitted through the first substrate 5 and incident on the optical sheet 3. 3 is emitted to the outside.

  The optical sheet 3 shown in FIG. 2 and FIG. 3 is laminated on the upper surface that is the surface on the light emission side of the first substrate 5 of the EL panel 2, and this optical sheet 3 includes the translucent substrate 12, the transparent substrate 12, and the transparent substrate 12. It is comprised with the lens layer 14 which has the uneven structure surface 13 laminated | stacked and formed on the optical base material 12. FIG. The concavo-convex structure surface 13 is, for example, a prism lens 15 having a substantially triangular cross section. In the first embodiment, the concavo-convex structure surface 13 is formed in one direction in the surface direction of the translucent substrate 12 and has a relatively large cross sectional substantially triangular shape. A plurality of columnar prism lenses 15A are arranged in parallel, and in other directions substantially orthogonal to the prism lens 15A, a plurality of columnar prism lenses 15B having a substantially triangular cross section having a different size from the prism lens 15A are arranged in parallel. Has been configured. In this case, the triangular vertices of the prism lenses 15A and 15B protrude in the emission direction, and the triangular bases of the prism lenses 15A and 15B are positioned in the incident direction.

  Moreover, the cross-sectional shape of the concavo-convex structure surface 13 is not limited to the above-mentioned triangle, and other appropriate cross-sectional shapes can be adopted. Moreover, the shape of the concavo-convex structure surface 13 is not limited to one type, and the lens layer 14 may be configured by combining two or more types of shapes of three or more types.

  Further, the lens layer 14 may be configured by arranging cylindrical lenses of the concavo-convex structure surface 13 in a one-dimensional direction, but is preferably configured by arranging in a two-dimensional direction as described above. . The two-dimensional arrangement of the concavo-convex structure surface 13 includes not only a configuration in which cylindrical lenses extending in one direction are arranged in parallel in a direction orthogonal to each other, but also a configuration in which lenses are arranged in a dot shape in a direction orthogonal to each other. An example of the configuration is a honeycomb arrangement.

  Here, the material of the optical sheet 3 will be described. As the translucent substrate 12, 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. Moreover, what has surface-treated like an easily bonding layer to the at least one surface of the translucent base material 12 can also be used. By adopting such a configuration, the adhesion between the EL panel 2 and the first substrate 5 in contact with the surface-treated one and the adhesion with the lens layer 14 are enhanced.

  In the present embodiment, an active energy ray-curable resin is used for the lens layer 14 having the concavo-convex structure surface 13. 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 the active energy ray-curable resin as the material of the lens layer 14, a material that is cured and has adhesiveness when irradiated with active energy rays (for example, ultraviolet rays) can be used.

  When the lens layer 14 is manufactured, the active energy ray-curable resin will be described later using, for example, an ultraviolet curable photopolymer, specifically, an acrylic polymer, an acrylic monomer, a photoinitiator and the like. Spherical translucent particles are mixed and an ultraviolet curable photopolymer is applied onto the translucent substrate 12. And the optical sheet 3 which has the desired lens layer 14 can be obtained by making it harden | cure in the state which pressure-bonded the metal mold | die (plate | plate) by which the pattern of the lens layer 14 was previously shape | molded to the ultraviolet curable photopolymer. .

  Here, in the case where a mold (plate) is pressure-bonded and formed using an active energy ray-curable resin as the material of the lens layer 14, the resin adhesion of a flat portion or the like in the external shape of the concavo-convex structure surface 13. If there is a very low part, when the active energy ray curable resin is cured, the part is released from the mold faster than the uneven part of the uneven part, and the part becomes uneven. A phenomenon called “Delami” occurs.

  Further, in the molding method of the lens layer 14, the rugged pattern portion (lens pattern) of the mold also has a rusted surface due to corrosion or the like, and a high aspect ruggedness that is the ratio of the height and width of the rugged structure surface 13. In a part or the like, it is difficult to peel off the mold after the actinic radiation curable resin is cured, and there is a possibility that a phenomenon of “resin removal” that the resin remains on the mold side may occur.

  Therefore, in the first embodiment of the present invention, “delamination” or “resin removal” is performed by adding spherical translucent particles to the active energy ray-curable resin forming the lens layer 14 in a predetermined range in advance. I tried to suppress it. Spherical translucent particles can exhibit the function of adjusting the curing shrinkage and release properties of the active energy ray-curable resin.

  Spherical translucent particles are made of organic particles made of, for example, styrene resin, acrylic resin, silicone resin, urea resin, formaldehyde condensate, glass beads, silica, alumina, calcium carbonate, metal oxide, and the like. Inorganic fine particles or dye pigments that absorb at a specific wavelength of visible light can be used, and these plural types of fine particles can be used in combination.

  Addition of spherical translucent particles can adjust the cure shrinkage rate when the active energy ray curable resin is cured, and the mold release property can be adjusted and the delamination phenomenon where the molded resin is peeled off from the mold before curing Can be prevented.

  In addition, the presence of spherical translucent particles on the surface of the molded lens layer 14 makes it easy to release the cured lens layer 14 from the mold, and the resin is removed such that the resin remains on the mold side. The phenomenon can be prevented.

  At this time, the lens layer 14 becomes a substantially uniform layer by appropriately selecting the kind of the spherical translucent particles and the translucent resin so that the refractive index difference is 0.001 or less. The effect can be used to the maximum.

  On the other hand, when it is desired to impart light diffusibility to the optical sheet 3, a desired light diffusibility is imparted to the lens layer 14 by appropriately selecting the kind of the spherical light transmissive particles and the light transmissive resin and providing a difference in refractive index. However, it is desirable that the difference in refractive index is 0.05 or more.

  Here, the percentage of the volume of the spherical translucent particles with respect to the total volume of the lens layer 14 of the optical sheet 3 is set in the range of 0.5 to 40%. In addition, this value is a volume percentage in the stage before hardening.

  Within this range, the spherical translucent particles are present in the vicinity of the surface as compared with the case where the spherical translucent particles are not added, so that the adhesive force between the cured active energy ray-curable resin and the mold is increased. Decreases and the releasability improves. In addition, the adhesiveness between the cured resin and the translucent substrate 12 is remarkably high, improving the reliability of the product, and the resin enters the fine pattern of the mold (plate), resulting in good transferability. is there. In addition, it is still better if the volume percentage is in the range of 1 to 30%.

  On the other hand, when the volume percentage is less than 0.5%, the lens layer 14 is cured when the mold pattern is transferred onto the translucent substrate 12 using the active energy ray-curable resin. Since the decrease in the adhesion between the resin and the mold is not sufficient, it does not lead to an improvement in releasability.

  Further, when the volume percentage exceeds 40%, the adhesion between the cured resin and the translucent substrate 12 is remarkably lowered, and the reliability of the product is impaired, and the translucent resin and the spherical shape are reduced. Depending on the combination with the light-transmitting particles, the resin viscosity is remarkably increased, so that the resin does not enter the fine pattern of the mold and the transferability is lowered.

Next, the relationship between the particle size of the spherical translucent particles and the shape of the concavo-convex structure surface 13 will be described.
First, the particle diameter of the spherical translucent particles will be described. The average particle diameter r of the spherical light-transmitting particles added to the light-transmitting resin is preferably in the range of 0.5 to 10 μm. If the average particle diameter r is out of this range, the ratio of particularly impairing the molding stability is high. The average particle diameter r of the spherical translucent particles is more preferably in the range of 2 to 10 μm, and both the molding stability of the lens layer 14 and the transfer rate are most preferable.

  Here, the average particle diameter r is measured by an electrical detection band method (Coulter principle). The “particle diameter” of this principle is the diameter of a sphere having the same volume as the particle. The average particle diameter r is the volume average diameter (arithmetic average) of the measurement data obtained by the above measurement.

  Next, the maximum height roughness (Rz) of the uneven structure surface 13 will be described. If Rz is smaller than 30 μm, a sufficient height as a lens pattern cannot be secured. For this reason, the characteristic as an optical sheet falls. Further, if Rz is larger than 100 μm, it becomes difficult to ensure the scratch resistance of the lens pattern, and the thickness of the optical sheet itself increases, so that the organic EL panel, which is particularly thin, is thickened. The problem occurs. For this reason, Rz was set to 30 to 100 μm (30 μm ≦ Rz ≦ 100 μm).

  The skewness (Rsk) of the concavo-convex structure surface 13 will be described. If Rsk is less than −1.5, the optical sheet has a shape with deep valleys, and the lens pattern molding die has sharp peaks, which reduces the printing durability of the die. On the other hand, when Rsk is larger than +1.5, a sharp mountain is present in the optical sheet, so that resin is likely to be taken out at this portion during lens pattern molding, and the molding stability is lowered. Furthermore, in this case, the scratch resistance of the lens sheet itself is also reduced. For this reason, Rsk was set to −1.5 to +1.5 (−1.5 ≦ Rsk ≦ 1.5).

  Moreover, the preferable relationship between the average particle diameter r of spherical translucent particle | grains and Rz of the uneven structure surface 13 is that r is 10% or less of Rz.

  Within this range, the viscosity of the active energy ray-curable resin is moderately suppressed to ensure a transfer rate, and the lens shape is not deformed by fine particles to ensure good optical characteristics and release from the mold. Sometimes, there is an advantage that the active energy ray-curable resin has good releasability and does not cause a phenomenon that the resin remains on the mold side at the time of release.

  On the other hand, when r exceeds 10% of Rz, the ratio of particles becoming large and deforming the lens shape increases, which impairs optical characteristics and is active energy ray curable resin when released from the mold. This causes a problem that the cured resin film is coherently broken and causes a phenomenon that the resin remains on the mold side.

  In the EL illumination element 1 shown in FIG. 1, the optical sheet 3 is laminated on the upper surface of the EL panel 2, and the optical sheet 3 is laminated on the surface of the first substrate 5 of the EL panel 2, for example, a glass substrate (not shown). ). For the bonding, a pressure-sensitive adhesive or an adhesive can be used, and the pressure-sensitive adhesive or the adhesive may be any resin-based material such as acrylic or urethane, and the translucent substrate 12 or a thermoplastic resin described later. Depending on the material, it can be appropriately selected. 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 a specific means of the crosslinking method using an adhesive or an adhesive, it can react with a carboxyl group, a hydroxyl group, an amino group, an amide group, or the like appropriately included in an acrylic polymer such as an isocyanate compound, an epoxy compound, or an aziridine compound as a crosslinking base point. There is a method using a so-called crosslinking agent in which a compound having a group 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. In addition, fine particles forming spherical light-transmitting particles may be added to these for the purpose of adjusting diffusion performance and adhesion with a glass substrate.

  The optical sheet 3 having a concavo-convex pattern is bonded to the outermost glass substrate of the EL panel 2 via an adhesive or an adhesive, thereby improving light extraction efficiency and light to fine particles added as spherical translucent particles. By imparting diffusibility, it is possible to reduce the phenomenon of color misregistration such as the color depending on the viewing angle, and it is also possible to form a hemispherical pattern by a corrosive method etc. with spherical translucent particles. When used in combination with a cylindrical lens, the scratch resistance can be improved, and it can also be used as an optical sheet for flat panel displays such as an optical sheet for liquid crystal backlights and an optical sheet for EL displays. .

  The optical sheet 3 according to the present embodiment has the above-described configuration, and a manufacturing method thereof will be described next.

FIG. 4 is a schematic view of an apparatus for manufacturing the optical sheet 3 according to the present embodiment.
The optical sheet 3 manufacturing apparatus 16 includes a translucent base material roll 17 that feeds the translucent base material 12 that is continuous in a sheet shape as a translucent base material sheet 12A, and fine particles in advance on the translucent base material sheet 12A. A resin supply nozzle 18 for applying an active energy ray-curable resin mixed with spherical translucent particles, and a cylindrical mold 19 forming a mold in which the transfer shape of the lens layer 14 is formed on a cylindrical surface. A mold pressing roll 20 that is pressure-bonded to the cylindrical mold 19, and an ultraviolet exposure device 21 that cures the resin by irradiating the active energy ray-curable resin applied to the cylindrical mold 19 with ultraviolet rays; And an optical sheet roll 22 that winds the translucent substrate sheet 12A on which the lens layer 14 is molded.

  The cylinder-shaped mold 19 as a cylinder plate here is formed, for example, by plating another metal in layers on a substantially cylindrical iron core. The other metal mentioned 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 cylindrical mold 19, and is intended for rust prevention and surface protection after the concave / convex pattern is applied. It is also possible to apply metal plating such as chrome. Moreover, the method of providing the concave-convex pattern on the cylindrical mold 19 can be appropriately selected from a cutting method using a lathe, a laser drawing, a corrosion method, or the like, or a combination of these methods as appropriate. 19 can be made.

  Next, a method for manufacturing the optical sheet 3 according to the present embodiment using the optical sheet 3 manufacturing apparatus 16 will be described.

  First, the translucent base material sheet 12A in which the translucent base material 12 continues in a sheet shape is fed out from the translucent base material roll 17, and the translucent property is transmitted from the resin supply nozzle 18 disposed facing the receiving roll 23. An active energy ray-curable resin in which fine spherical light-transmitting particles are previously added and uniformly dispersed is applied onto the base sheet 12A.

  The translucent substrate sheet 12A 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 cylindrical die 19, and The active energy ray-curable resin is molded by being sandwiched between the die crimping rolls 20, and is molded along the concave / convex pattern of the cylindrical die 19.

  Then, the translucent substrate sheet 12A formed by the cylindrical mold 19 is cured by active energy rays such as ultraviolet rays irradiated from the ultraviolet exposure device 21, and is wound around the optical sheet roll 22 via a tension roll. It is done.

  Then, the optical sheet 3 is obtained by cutting the translucent substrate sheet 12A for each unit of the translucent substrate 12 on which the lens layer 14 is formed in a separate process.

  As described above, according to the manufacturing method of the optical sheet 3 according to the first embodiment and the optical sheet 3 obtained by this method, the lens layer 14 has various complicated surface shapes such as a fine surface shape and a flat surface shape. Even if it has a surface shape, spherical translucent particles were selected and added to the active energy ray curable resin in the transfer molding using the cylindrical mold 19 in which those surface shapes were combined. In addition to being easy to mold, the transfer rate and appearance of the active energy ray-curable resin with respect to the cylindrical mold 19 are good, and the plate release from the cylindrical mold 19 is reliable, so It is possible to prevent a phenomenon such as delamination that occurs before the flat portion is released from being cured, or a resin that remains in the cylindrical mold 19 at the time of release.

  In addition, by adding spherical translucent particles to the active energy ray curable resin in advance, it is effective for the cylindrical mold 19 in which rust is generated on the surface because a long time has passed after the production. The life of the metal mold 19 can be extended more than usual, which leads to a cost reduction effect.

  In addition, an EL lighting element 1 and an illuminating device using the EL lighting element 1 as a light emitting device can be obtained by using the optical sheet 3 manufactured by such a manufacturing method, and illumination with good light emission and high illuminance can be obtained. It is done.

  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 embodiment. Rather, changes can be made as appropriate without departing from the spirit of the invention.

Examples of the optical sheet of the present invention will be described below.
In the optical sheet 3 of the present invention shown in FIGS. 2 and 3, the concavo-convex structure surface 13 is a prism lens having a substantially triangular cross section, for example, and unit lenses 15A and 15B having the same shape arranged in parallel are orthogonal to each other. It has become. In this example, the cylinder was manufactured by the manufacturing method using the manufacturing apparatus using the cylindrical mold 19 shown in FIG. The cylindrical mold 19 was produced by forming the inverted shape of the concavo-convex structure surface 13 by a cutting method. In the mold in this case, the concavo-convex portion is formed in a substantially triangular shape corresponding to the substantially triangular cross section of the concavo-convex structure surface 13.

  The shape of the mold is not limited to the above-described embodiment, and is appropriately set according to the shape of the optical sheet 3.

  Then, a urethane acrylate resin is used as the active energy ray-curable resin as the material of the lens layer 14, PMMA fine particles having an average particle diameter of 3 μm are used as the spherical translucent particles, and the spherical translucent particles with respect to the entire volume of the lens layer The optical sheet 3 was produced with a volume ratio of 30 (%).

  With respect to the produced optical sheet 3, the maximum height roughness Rz and the skewness Rsk were measured. The measurement was performed three times each in four directions in which the direction of the sample was changed by about 45 °, and when Rz and Rsk were determined with the direction having the largest Rz among the average values as the measurement direction, Rz = 36 μm, Rsk = 0. .35, both molding stability and transfer rate were good. As a method for measuring the surface property parameter, a surface roughness parameter was measured with a stylus roughness measuring machine based on JIS B0601, JIS B0633, JIS B0651 under the conditions of a cutoff value λs = 8 μm and λc = 2.5 mm. Moreover, the evaluation length was 12.5 mm, the stylus tip radius was 5 μm, the taper angle was 60 °, and the average value of the measured values at three points in the concavo-convex structure surface was calculated.

DESCRIPTION OF SYMBOLS 1 EL illumination element 2 EL panel 3 Optical sheet 5 1st board | substrate 6 2nd board | substrate 7 Light-emitting structure 8 Anode 9 Cathode 10 Light-emitting layer 12 Translucent base material 12A Translucent base material sheet 13 Uneven structure surface 14 Lens layer 15 , 15A, 15B Prism lens 16 Manufacturing device 17 Translucent substrate roll 18 Resin supply nozzle 19 Cylinder-shaped mold (cylinder version)
20 Die crimping roll 21 UV exposure device 22 Optical sheet roll 23 Receiving roll

Claims (8)

A lens layer made of a translucent resin containing spherical translucent particles is laminated on at least one surface of the translucent substrate, and the lens layer is opposite to the translucent substrate. In the optical sheet having a concavo-convex structure on the surface located,
The translucent resin includes an active energy ray curable resin,
The ratio of the spherical translucent particles to the total volume of the lens layer in the lens layer is 0.5 to 40 by volume ratio,
The average particle diameter r of the spherical translucent particles is 0.5 μm ≦ r ≦ 10 μm,
The maximum height roughness Rz of the concavo-convex structure surface is 30 μm ≦ Rz ≦ 100 μm,
The range of the skewness Rsk of the roughness curve of the concavo-convex structure surface is −1.5 ≦ Rsk ≦ 1.5,
And the relationship between the average particle diameter r of the said spherical translucent particle | grains and the said maximum height roughness Rz is r / Rz <= 0.1, The optical sheet characterized by the above-mentioned.   The optical sheet according to claim 1, wherein a difference in refractive index between the spherical translucent particles and the translucent resin is 0.001 or less.   The optical sheet according to claim 1, wherein a difference in refractive index between the spherical translucent particles and the translucent resin is 0.05 or more.   It has at least an adhesive layer formed of a heat-fusible adhesive or a pressure-sensitive adhesive, and the adhesive layer, the translucent substrate, and the lens layer are laminated in this order. The optical sheet according to any one of claims 1 to 3. A manufacturing method for manufacturing the optical sheet according to any one of claims 1 to 4,
A translucent resin forming step of forming the translucent resin containing the spherical translucent particles on at least one surface of the translucent substrate;
After the translucent resin forming step, the plate having a concavo-convex shape is used to press the concavo-convex shape surface of the plate against the outer surface of the translucent resin, thereby imparting the concavo-convex shape of the plate to the translucent resin. After molding, a resin curing step of irradiating the translucent resin with active energy rays to cure the active energy ray curable resin;
A method for producing an optical sheet, comprising:   The plate is formed of a cylindrical plate, and the concave and convex shape of the plate is shaped into the translucent resin by pressing the cylindrical plate against the translucent resin with a pressing roll. 6. A method for producing an optical sheet according to 5.   The optical sheet according to any one of claims 1 to 4 is laminated on an outermost surface on a light emission side of an EL panel in which a light emitting structure is disposed on a light-transmitting first substrate. EL element characterized by.   An illumination device comprising the EL element according to claim 7 as a light emitting means.

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