JP2016099476A - Optical film for illumination and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film for illumination, which can be made thin with a simple structure, suppresses glare of light in an oblique direction while achieving illumination in a brighter state of light just below the film, and has a structure that can be easily cleaned.SOLUTION: The optical film includes a light-transmitting substrate layer 21 and a louver layer 22 formed on the substrate layer, and has a smooth surface on at least one of top and back surfaces. The louver layer includes: light-transmitting portions 23 arranged at a predetermined interval along one surface of the substrate layer and formed of a light-transmitting resin; and intermediate portions 24 formed between the light-transmitting portions and formed of a resin having a refractive index smaller than that of the light-transmitting portions, or intermediate portions 24 formed between the light-transmitting portions and formed of a resin having a refractive index equal to or smaller than that of the light-transmitting portions and containing a light-scattering material dispersed therein.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optical film used in a lighting device and a lighting device to which the optical film is applied.

  With respect to lighting devices arranged on the ceiling, in particular, many lighting devices arranged on a ceiling in a wide space such as an office, the light from the lighting devices at separate positions may feel dazzling. In addition, since the lighting device is sometimes looked up obliquely from below, it feels dazzling. On the other hand, by irradiating light directly under the lighting device brightly and efficiently, the hand can be brightened and the original function of the lighting device can be exhibited.

  From this point of view, for example, Patent Document 1 discloses a louver for restricting light irradiation in an oblique direction and irradiating more light downward.

Japanese Patent Laid-Open No. 2-40804

  However, the louver disclosed in Patent Document 1 has a complicated structure, and it has been difficult to reduce the thickness. In particular, the application of thick louvers to many lighting devices may affect the overall appearance of the room. Further, as described in Patent Document 1, such a louver is formed in a lattice shape or a wedge shape, and the front and back surfaces are not smooth surfaces, so it is difficult to clean them efficiently.

  Therefore, in view of the above-described problems, the present invention can be thinned with a simpler structure, light in an oblique direction suppresses glare, and light directly below can be illuminated in a brighter state and is easy to clean. It is an object to provide an optical film for illumination having a structure. Moreover, the illuminating device to which this optical film is applied is provided.

  The present invention will be described below. Here, for easy understanding, reference numerals used in the drawings are written in parentheses. However, the present invention is not limited to the form described in the drawings.

  The invention according to claim 1 is an optical film for illumination (20) used in the illumination device (10), the substrate layer (21) having translucency, and a louver formed on the substrate layer. A louver layer arranged at a predetermined interval along one surface of the base material layer, and a light transmission part (23) formed of a resin that transmits light, and a light transmission part And an intermediate portion (24) formed of a resin having a refractive index smaller than that of the light transmitting portion, and at least one of the front and back surfaces is a smooth surface.

  Invention of Claim 2 is the optical film (20) for illumination used for an illuminating device (10), Comprising: The base material layer (21) which has translucency, and the louver formed on the base material layer The louver layer is arranged at a predetermined interval along one surface of the base material layer, and the light transmission part (23) formed of a resin that transmits light, and the light transmission part And an intermediate portion (24) in which a material that scatters light is dispersed, and at least one of the front and back surfaces is a smooth surface.

  The invention according to claim 3 is the optical film for illumination (20) according to claim 1 or 2, wherein the light transmission part (23) and the intermediate part (24) are along one direction of the surface of the base material layer. It extends and is arranged in a direction different from the extending direction.

  According to a fourth aspect of the present invention, in the optical film for illumination (20) according to any one of the first to third aspects, two louver layers are laminated, and a light transmission part and an intermediate part of one louver layer extend. The direction and the direction in which the light transmission part and the intermediate part of the other louver layer extend are orthogonal to each other in plan view.

  The invention according to claim 5 is the lighting device main body (11), the light source (12) arranged in the lighting device main body, and any one of claims 1 to 4 arranged in the lighting device main body so as to cover the light source. It is an illuminating device (10) provided with the optical film for illumination (20) of description.

  According to a sixth aspect of the present invention, in the illumination device (10) according to the fifth aspect, the light source (12) is a fluorescent lamp or a light emitting diode.

  According to the present invention, the thickness can be reduced and cleaning can be facilitated because the surface is a smooth surface. Further, the light downward obliquely suppresses glare, and the light directly below can be illuminated in a brighter state.

1 is a perspective view of a lighting device 10. FIG. 2 is a cross-sectional view of the lighting device 10. FIG. It is the figure which expanded and represented a part of cover 13. FIG. It is a figure explaining the space | interval part 24. FIG. FIG. 3 is a diagram illustrating Example 1. It is a figure explaining the comparative example 1. FIG.

  The present invention will be described below based on embodiments shown in the drawings. However, the present invention is not limited to the embodiment. In the drawings shown below, for the sake of easy understanding, minute elements and thin elements are sometimes exaggerated and sometimes expressed thickly. Some of the repetitive symbols are omitted.

  FIG. 1 is a diagram illustrating a first embodiment, and is a perspective view of a lighting device 10 arranged on a ceiling of a building as viewed from obliquely below. FIG. 2 schematically shows an end view of the lighting device 10 cut along the line indicated by II-II in FIG. FIG. 3 shows an enlarged view of the part indicated by III in FIG.

  As can be seen from these drawings, the lighting device 10 includes a lighting device body 11, a light source 12, and a cover 13.

  The illuminating device main body 11 is a structural member that holds and functions each component included in the illuminating device 10, and in this embodiment, is formed in a box shape having an open portion on the lower surface side. The form of the illumination device main body 11 is not particularly limited, and a known one can be applied. Therefore, the illumination device main body 11 may be provided with a reflection means, or other control boards provided in the illumination device may be arranged.

  The light source 12 is a light emission source. The type of the light source 12 is not particularly limited, and a known light source such as a fluorescent lamp or a light emitting diode (LED) can be applied. As is well known, the light source 12 is configured to be fixed to the illumination device body 11 and emit light.

  The cover 13 is disposed so as to cover the open portion of the illuminating device body 11, and is positioned so as to cover each component member and the light source 12 disposed in the illuminating device body 11. In this embodiment, the cover 13 includes a cover main body 14 and an illumination optical film 20.

The cover main body 14 is a member that is a base of the cover 13 and is formed in a box shape having an open portion on the upper side as in the present embodiment, for example, and is sealed by overlapping the open portion with the open portion of the lighting device main body 11. A box-like shape is formed, and each component such as the light source 12 is included therein.
The cover main body 14 is formed of a material that transmits light due to its properties, and has a certain degree of strength. The specific material is the same as that of a known cover body, and for example, an acrylic resin can be used.

  The illumination optical film 20 controls the light emitted from the light source 12 as will be described later, and emits light in a manner that is bright for the lower part and bright but not dazzling for the oblique lower part. It is a film. As can be seen from FIG. 3, the illumination optical film 20 includes a base material layer 21 and a louver layer 22.

  The base material layer 21 is a layer serving as a base material for forming the louver layer 22 and has a light-transmitting property and supports the louver layer 22 so as to prevent deformation. From this viewpoint, as specific examples of the material constituting the base material layer 21, for example, a transparent resin mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, epoxy acrylate, urethane acrylate The reactive resin (ionizing radiation curable resin etc.) can be mentioned.

  Although the thickness of the base material layer 21 is not specifically limited, It is preferable that they are 25 micrometers or more and 300 micrometers or less. If the thickness of the base material layer 21 is out of this range, there is a possibility of causing a problem in workability. For example, if the base material layer 21 is too thin, wrinkles are likely to occur. Moreover, if the base material layer 21 is too thick, it will become difficult to wind up in an intermediate process.

  The louver layer 22 is light for the light incident from one side (that is, the light incident from the light source 12 side) immediately below and around the light, and bright at an angle below. It is a layer that can emit light to the other surface side (that is, the illuminated target side) in a non-dazzling manner. In this embodiment, the louver layer 22 has the cross section shown in FIGS. 2 and 3 and has a shape extending in the direction perpendicular to the paper surface (see also FIG. 1). That is, in the cross section shown in FIG. 2 and FIG. 3, a trapezoidal light transmission portion 23 and an intermediate portion 24 between the adjacent light transmission portions 23, each having a cross section formed in a trapezoidal recess. In this embodiment, adjacent light transmission parts 23 are connected to each other on the base material layer 21 side from the light transmission part 23. And the light transmission part 23 and the intermediate part 24 have the said cross section, are extended in one direction of a sheet | seat surface, and the several light transmission part 23 and the intermediate part 24 are alternately arranged in the direction different from the said one direction. .

  The light transmitting portion 23 is a portion that transmits light. In this embodiment, the light transmitting portion 23 has a trapezoidal cross section in the cross section shown in FIGS. Has a long bottom. Preferably, the light transmission part 23 transmits light without scattering. Thereby, bright light can be emitted immediately below. Here, “transmits without scattering light” means that it is a part formed without adding a material that intentionally scatters light, and light passes through a material that is not intended to scatter light. It is permissible for scattering to occur inevitably when passing through.

The material which comprises the light transmissive part 23 may be the same as the base material layer 21 and the cover main body 14, and may differ. However, if there is a difference in refractive index between the two, the possibility that light will be reflected at the interface increases, so even if they are the same material or different materials, the refractive index difference is small or there is no refractive index difference. It is preferable.
When the light transmission part 23 and the base material layer 21 are comprised with the same material, the base material layer 21 and the light transmission part 23 can also be formed integrally. Further, even when the light transmission part 23 and the base material layer 21 are made of different materials, and even when they are made of the same material, the base material layer 23 and the light transmission part 24 are separately formed, You may laminate | stack by a means.

  Examples of the material constituting the light transmitting portion 23 include transparent resins mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, etc., and epoxy acrylate and urethane acrylate reactive resins (ionizing radiation curing). Mold resin).

  The light transmission parts 23 are arranged at predetermined intervals in the direction along the sheet surface. Therefore, a recess having a trapezoidal cross section is formed between adjacent light transmission portions 23. The concave portion is a groove having a trapezoidal cross section having a long lower base on the upper bottom side of the light transmitting portion 23 and a short upper base on the lower bottom side of the light transmitting portion 23, and is necessary to be described later The intermediate portion 24 is formed by being filled with a new material.

  In the present embodiment, the intermediate portion 24 is a portion that scatters and transmits the light that has reached here, and in addition to the light that is scattered and transmitted, the light that reaches the interface under a predetermined condition is totally reflected. It is also configured to do.

In order to scatter the light that has reached the inside of the intermediate portion 24, for example, as shown in FIG. 4, pigments and particles can be dispersed in the intermediate portion 24 in a material serving as a binder. FIG. 4 is a diagram schematically showing an enlarged cross section of the space 24.
The pigment preferably has a concealing property, and examples thereof include a white pigment and a silver pigment. Examples of the white pigment include metal oxides such as titanium oxide, titanium dioxide, magnesium oxide, and zinc oxide. On the other hand, examples of the silver pigment include metals such as aluminum and chromium.
The particles are preferably particles having a refractive index different from that of the binder, and examples thereof include glass particles and resin particles.

Since the total reflection is performed under a predetermined condition, the intermediate portion 24 can be filled with a resin having a refractive index lower than that of the light transmission portion 23. According to this, total reflection can be achieved at the interface between the light transmission part 23 and the intermediate part 24 if the incident angle of light satisfies the total reflection condition based on the refractive index difference. The greater the difference in refractive index, the more light that can be totally reflected. The specific difference in refractive index is not particularly limited, but examples include greater than 0 and 0.16 or less.
On the other hand, the refractive index difference is 0, or the intermediate portion 24 is filled with a resin having a higher refractive index than the light transmitting portion 23, so that the light transmitting portion 23 and the intermediate portion are not subjected to such total reflection. All of the light reaching the interface with 24 can be advanced to the interspace 24. Such a form may be sufficient.

  Since the intermediate portion 24 is formed in the concave portion between the adjacent light transmitting portions 23, the shape thereof is also along the concave portion. Therefore, in this embodiment, the intermediate portion 24 has a substantially trapezoidal cross section having a short upper base on the base material layer 21 side and a long lower bottom on the light source 12 side, and has a hypotenuse therebetween. This hypotenuse constitutes an interface with the light transmission part 23 and becomes a common hypotenuse.

The angle θ ₁ (see FIG. 3) of the hypotenuse in the cross section of the intermediate portion 24 (light transmission portion 23) is not particularly limited, but is preferably 1 ° or more and 10 ° or less with respect to the normal to the sheet surface. . By making θ ₁ within this range, both productivity and optical performance can be achieved.

  The pitch at which the interspaces 24 are arranged is not particularly limited, but is preferably 10 μm or more and 200 μm or less, and more preferably 100 μm or more and 200 μm or less. If the pitch of the interspace 24 is narrower than 10 μm, it is difficult to obtain a desired effect to be described later by the louver layer 22, and there is a possibility that the light transmitted through the light transmitting portion 23 becomes rainbow-like due to the diffraction phenomenon. . Further, if the pitch of the intermediate portion 24 is too larger than 200 μm, it becomes difficult to form the intermediate portion 24, or when the louver layer 22 is manufactured as described later, the mold releasability and workability are reduced. May cause problems. The opening width of the interspace 24 (the width on the light source 12 side in the cross section shown in FIG. 4) is not particularly limited, but is preferably 5 μm or more and 150 μm or less. When the opening width of the intermediate portion 24 is narrower than 5 μm, it is difficult to obtain a desired effect described later by the louver layer 22. Further, if the opening width of the intermediate portion 24 is larger than 150 μm, it may be difficult to form the intermediate portion 24, or there may be a problem in mold releasability and workability when the louver layer 22 is manufactured. is there.

  The thickness of the interspace 24 (the size of the louver layer 22 in the thickness direction) is not particularly limited, but is preferably 50 μm or more and 300 μm or less. If the space 24 is thinner than 50 μm, it may be difficult to obtain a desired effect, which will be described later, or it may be difficult to perform fine processing (such as formation of the space 24). Moreover, when the thickness of the intermediate portion 24 is more than 300 μm, there is a possibility that a problem may occur in workability such as difficulty in releasing the mold when the louver layer 22 is manufactured.

In the present invention, the shapes of the light transmission part and the intermediate part are not limited to the form shown in FIG. Therefore, in the cross section corresponding to the cross section shown in FIG. 3, the light transmission portion may be rectangular, and the portion corresponding to the hypotenuse of the trapezoid is curved (the tangent of the curve is the same as the above θ _{1 in} each portion) there is preferred.) or line-shaped (have each line constituting a polygonal line may be made it is preferable.) is the same conditions as above theta _1.

  Such a louver layer 22 is laminated | stacked on the light emission surface side of the cover main body 14 so that FIG. 2, FIG. 3 may show. Such lamination can be performed by, for example, an adhesive or an adhesive. In this embodiment, as shown in FIGS. 2 and 3, the louver layer 22 is disposed so as to overlap the cover main body 14. However, the present invention is not limited to this, and the base material layer 21 side may be laminated on the cover main body 14. In this case, the trapezoidal cross sections of the light transmission part 23 and the intermediate part 24 are opposite to those shown in FIGS.

  When the light source is a straight tube fluorescent lamp, it is preferable that the direction in which the fluorescent lamp extends and the direction in which the light transmission part and the light absorption part extend are parallel to each other. When the light source is an LED and a plurality of LEDs are arranged in one direction, it is preferable that the direction and the direction in which the light transmission part and the light absorption part extend are parallel to each other. As a result, the effects of the present invention can be achieved more efficiently.

  Here, at least one of the front and back surfaces of the illumination optical film 20 is a smooth surface. Thereby, the ease of cleaning and the adhesiveness to the cover main body 14 are improved. In addition, a smooth surface means here that the height difference with the adjacent unevenness | corrugation in a surface is less than 100 micrometers. More preferably, it is less than 10 μm.

  Moreover, since it can comprise thinly according to the optical film 20 for illumination of the above structures, even if it is used for many illuminations arrange | positioned on the ceiling, a clean impression can be given without being conspicuous.

  In addition, the optical film 20 for illumination demonstrated above can be manufactured as follows, for example.

  First, a die roll is prepared in which irregularities capable of transferring the light transmitting portion 23 of the louver layer 22 are provided on the outer peripheral surface of a cylindrical roll. And the base material used as the base material layer 21 is inserted between a mold roll and the nip roll arrange | positioned so as to oppose this. And a mold roll and a nip roll are rotated, supplying the composition before hardening which comprises the light transmissive part 23 between one surface and a mold roll among base materials. As a result, the concave / convex concave portions formed on the surface of the mold roll are filled with the composition constituting the light transmitting portion 23, and the composition conforms to the concave / convex surface shape of the mold roll.

  Here, as a composition which comprises the light transmissive part 23, although what was mentioned above is preferable, it is as follows more specifically. That is, the photocurable resin composition which mix | blended the reactive dilution monomer and the photoinitiator with the photocurable prepolymer can be used. As these, known ones can be used as appropriate.

  Light is irradiated from a base material side with a light irradiation apparatus with respect to the composition before hardening which is pinched | interposed between a metal mold | die roll and a base material and comprises the light transmission part 23 with which this was filled. Thereby, the composition which comprises the light transmissive part 23 can be hardened, and the shape can be fixed. And the base material layer 21 and the shape | molded light transmission part 23 are released from a metal mold | die roll with a mold release roll.

Next, the intermediate part 24 can be formed by filling the concave part formed between the adjacent light transmission parts 23 with the composition before curing that constitutes the intermediate part 24 and curing it. Specifically, the composition before the curing that constitutes the intermediate portion 24 is excessively supplied to the concave portions between the adjacent light transmission portions 23, and the amount is adjusted by scraping off the surplus portion with a blade. Fill the composition. Then, the composition filled in the recess is cured by an appropriate method.
In this way, the louver layer 22 can be formed on the base material layer 21 to form the illumination optical film 20.

  In addition, from a viewpoint of scratch resistance and contamination resistance, a hard coat layer may be provided on the surface opposite to the light source in the illumination optical film. The hard coat layer can be formed as a transparent resin layer, and is preferably formed as a cured resin layer obtained by curing a curable resin from the viewpoint of resistance to scratches and surface contamination. Specifically, an ionizing radiation curable resin, other known curable resins, or the like may be appropriately employed according to the required performance. Examples of the ionizing radiation curable resin include acrylate-based, oxetane-based, and silicone-based resins.

  The optical film for illumination as described above has a simple structure and can be made thin. The thickness is not particularly limited, but can be about 75 μm to 700 μm. Therefore, even if this is applied to a lighting device, it is possible to reduce the influence on the appearance.

  Next, the main optical path when the illumination device 10 is installed on the ceiling and illuminated will be described as an example. 2 to 4 schematically show examples of optical paths for explanation. Note that the optical path example is conceptually shown, and does not strictly represent the degree of refraction or reflection.

  As shown by a plurality of straight arrows in FIG. 2, light is emitted from the light source 12 in various directions, and most of the light finally passes through the cover 13 and is emitted downward. At this time, the light passes through the illumination optical film 20.

The light that reaches the illumination optical film 20 is transmitted through the illumination optical film 20 and emitted downward, for example, as follows.
The light L31 shown in FIG. 3 is an example of an optical path of light that has been transmitted through the light transmitting portion 23 without reaching the interface between the light transmitting portion 23 and the intermediate portion 24. Since such light has to enter the light transmitting portion 23 at an angle and position so as not to reach the interface between the light transmitting portion 23 and the intermediate portion 24, the emitted light has an angle immediately below or close to immediately below. . Therefore, this light is light that illuminates the area immediately below and near the illumination device 10 brightly, and does not significantly affect the glare when the illumination device 10 is looked up obliquely from below.

  Since the light L32 shown in FIG. 3 is incident on the light transmission part 23 at a large angle with respect to the normal direction (thickness direction) of the illumination optical film 20, the light L32 passes through the interface with the intermediate part 24 and enters the intermediate part 24. It is an example of the optical path of the light which went to. Such light L32 is scattered and emitted by a substance that scatters the light contained in the intermediate portion 24, for example, as shown by an optical path example L41 to an optical path example L43 in FIG. Accordingly, the light emitted obliquely downward can be scattered to suppress the feeling of glare while ensuring the brightness.

  If there is a difference in refractive index between the light transmission part 23 and the intermediate part 24, as indicated by L33 in FIG. 3, the difference in refractive index and the light incident on the interface between the light transmission part and the light absorption part Depending on the incident angle condition, if the angle is equal to or greater than the total reflection critical angle, the light is totally reflected, changed in direction, and emitted. This also makes it possible to control the light.

  As described above, according to the illumination optical film 20 and the illumination device 10 using the same, the light downward obliquely suppresses glare, and the light directly below can be illuminated in a brighter state. Since it can be thinned with a simple structure, the influence on the appearance can be kept small.

  In the above embodiment, an example is shown in which one louver layer 22 is applied, but in addition to this, another louver layer may be laminated. In the other louver layer added at this time, the direction in which the light transmission part and the intermediate part extend is preferably different from the direction in which the light transmission part 23 and the intermediate part 24 of the louver layer 22 extend. That is, when the illumination optical film is viewed in plan (when viewed from the surface of the illumination optical film), the light transmission portion of the additional louver layer and the light transmission portion 23 of the louver layer 22 are added. This is an aspect that intersects at a predetermined angle. Among these, the intersecting angle is preferably 90 °. As a result, the above-described effects can be obtained in a well-balanced manner in all directions within the range illuminated by the lighting device.

In the above embodiment, the mode in which the intermediate portion 24 of the louver layer 22 has light diffusibility has been described. However, the intermediate portion does not necessarily have light diffusibility. That is, the intermediate part is formed of a transparent resin having no light diffusibility, and the transparent resin constituting the intermediate part has a lower refractive index than the light transmitting part. According to this, even if there is no light diffusibility in the intermediate portion, light control by total reflection is possible as indicated by L33 as an example of the optical path in FIG.
Even in this case, since at least one of the front and back surfaces of the illumination optical film can be formed of a smooth surface, the same effects can be achieved with respect to ease of cleaning and improvement in adhesion to the cover body.

<Example 1>
In Example 1, an illumination optical film was produced following the illumination optical film 20. More specifically, an illumination optical film having the following shape was obtained. FIG. 5 shows the form of the louver layer.
(Base material)
PET film, trade name: A4300, manufactured by Toyobo Co., Ltd., thickness 100 μm
(Louver layer shape)
-Light transmission part opening width (light source side) A: 80 μm
-Light transmission part opening width (light emission side) B: 100 μm
・ Width between light sources (light source side) C: 25 μm
・ Space width (light emission side) D: 5 μm
・ Thickness direction size E: 160μm
-Leg part inclination angle θ ₁ : 1.5 °

(Preparation of optical film for lighting)
The illumination optical film was produced as follows.
(1) Preparation of composition for light transmitting part Bisphenol A ethylene oxide / xylylene diisocyanate / phenoxyethyl acrylate / 2-hydroxyethyl acrylate / bismuth tri (2-ethylhexanoate) = 30: 15: 50: 5: 0.02 And reacted at 80 ° C. for 10 hours to obtain a photocurable prepolymer (P1).
On the other hand, bisphenol A ethylene oxide / isophorone diisocyanate / phenoxyethyl acrylate / bismuth tri (2-ethylhexanoate) = 30: 20: 50: 0.02 was mixed and reacted at 80 ° C. for a time to produce a photocurable prepolymer (P2 )
Next, 30 parts by mass of the photocurable prepolymer (P1), 30 parts by mass of the photocurable prepolymer (P2), 10 parts by mass of phenoxyethyl acrylate as the reactive dilution monomer (M1), the reactive dilution monomer ( 30 parts by mass of bisphenol A ethylene oxide as M2), 0.03 parts by mass of a phosphate ester of tetradecanol ethylene oxide 10 mol as a mold release agent (S1), stearyl as a mold release agent (S2) Mixing and homogenizing 0.03 part by weight of 15 moles of amine ethylene oxide adduct and 1 part by weight of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufacturer name: BASF) as photopolymerization initiator (I1) Thus, a light transmitting part constituting composition was obtained.
The light transmitting part constituting composition was applied at a thickness of 100 μm, and the light transmitting part constituting composition was cured by irradiating an ultraviolet ray of 800 mJ / cm ² with a high pressure mercury lamp. Using ATAGO Co., Ltd., the refractive index of 589 nm was measured and found to be 1.550.

(2) Production of mold roll A mold roll used for production of the louver layer was produced as follows. The mold roll was cylindrical and was plated with copper, and the copper plated portion was cut with a cutting tool to form a groove corresponding to the light transmitting portion. A diamond bite was used for cutting. Grooves were formed by cutting the outer periphery of the copper plating layer of the mold roll at a predetermined pitch in the roll axis direction, and chrome plating was applied after the cutting.

(3) Formation of light transmission part The base material demonstrated by said (1) was conveyed between the metal mold | die roll produced by said (2), and the nip roll prepared separately. In accordance with the conveyance of the base material, the light transmitting portion constituting composition obtained in (1) above is supplied from the supply device onto the base material layer of the base material, and the base material is pressed by the pressing force between the mold roll and the nip roll. The light transmitting portion constituting composition was filled between the layer and the mold roll. Then, 800 mJ / cm < ² > of ultraviolet rays were irradiated from the base material side with the high pressure mercury lamp, the light transmissive part constituent composition was hardened, and the light transmissive part was formed. Then, the light transmission part was released from the mold roll with a peeling roll to produce a sheet (intermediate member) including the light transmission part.
About this light transmission part, the elastic modulus was measured by applying a load to the micro indenter material using a compression micro hardness tester (FISCHER HM2000) and unloading the material. At this time, the load force was 100 mN, the load speed was 4 μm / 10 seconds, and the holding time was 60 seconds. As a result, the elastic modulus of the light transmission part was 800 MPa. At this time, the light transmission part has a shape corresponding to the groove of the mold roll.

(4) Adjustment of inter-layer composition: 42 parts by mass of urethane acrylate as the photocurable prepolymer (P3), 18 parts by mass of epoxy acrylate as the photocurable prepolymer (P4), and as the reactive dilution monomer (M3) 35 parts by mass of tripropylene glycol diacrylate, 5 parts by mass of methoxytriethylene glycol acrylate as the reactive diluent monomer (M4), 5 parts by mass of titanium oxide as the light scattering agent (D1), 1 as the photopolymerization initiator (I1) 7 parts by mass of hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufacturer name: BASF) was mixed and homogenized to obtain an intermediate composition.
The components excluding the scattering agent in the intermediate composition were coated at a thickness of 100 μm, cured by irradiating with 800 mJ / cm ² of ultraviolet light with a high pressure mercury lamp, and a multiwavelength Abbe refractometer (manufactured by Atago Co., Ltd.). ) To measure the refractive index of 589 nm, it was 1.49. That is, the refractive index difference between the light transmission part and the intermediate part is 1.55-1.49 = 0.06.

(5) Formation of interspace part The composition which comprises the interspace part obtained by said (4) was supplied from the supply apparatus on the intermediate member produced by said (3). Further, using a doctor blade arranged so as to extend substantially perpendicular to the advancing direction of the intermediate member, the intermediate composition supplied on the intermediate member is in a groove formed in the intermediate member (a groove between the light transmitting portions). The composition constituting the intermediate portion was scraped off. Then, 800 mJ / cm < ² > ultraviolet-ray was irradiated with the high pressure mercury lamp, the intermediate part composition was hardened, and the intermediate part was formed with the hardened intermediate part composition. In this state, a recess having a depth of 6 μm was generated on the surface of the intermediate portion. When the above process was performed once more, the depression on the surface of the intermediate portion had a depth of 3 μm. That is, the unevenness of the unevenness of the front and back surfaces of the illumination optical film obtained as described above is 3 μm, which is a smooth surface.

(Lighting device and its installation)
The illumination optical film produced as described above was bonded to an acrylic plate to form a cover, followed by an illumination apparatus following the example of the illumination apparatus 10, and installed on the ceiling. In this example, the light source is a straight tube fluorescent lamp, and the longitudinal direction of the fluorescent lamp is the same as the direction in which the light transmitting portion of the illumination optical film extends.

<Example 2>
Two optical films for illumination prepared in Example 1 were prepared and laminated. At this time, they were arranged so that the direction in which both light transmitting portions extend was 90 ° in plan view. This example also has the same smooth surface as in Example 1.

<Example 3>
In the adjustment of (4) the interspace constituent composition described in Example 1, 5 parts by mass of titanium oxide was mixed with the same raw material as that constituting the light transmitting portion constituent composition, homogenized, and A constituent composition was obtained. At this time, the refractive index was 1.550. Therefore, in this example, the refractive index of the light transmission part and the refractive index of the intermediate part are the same. Other configurations were the same as those in Example 1.

<Example 4>
In the adjustment of (4) the interspace constituent composition described in Example 1, 5 parts by mass of titanium oxide was mixed with the same raw material as that constituting the light transmitting portion constituent composition, homogenized, and A constituent composition was obtained. At this time, the refractive index was 1.550. Therefore, in this example, the refractive index of the light transmission part and the refractive index of the intermediate part are the same. Other configurations were the same as those in Example 2.

<Comparative Example 1>
A plurality of diffused light control plates 50 (Sumipex (registered trademark), ES055, Sumika Acrylic Sales Co., Ltd.) were arranged so that the plate surfaces face each other at a pitch of 50 mm as schematically shown in FIG. The height (vertical size) of the diffused light control plate was 120 mm. It arranged in the direction orthogonal to the longitudinal direction of a fluorescent lamp.

<Comparative Example 2>
Following the example of Comparative Example 1, a plurality of diffused light control plates (Sumipex (registered trademark), ES055, Sumika Acrylic Sales Co., Ltd.) were arranged so that the plate surfaces face each other at a pitch of 50 mm. The height (vertical size) of the diffused light control plate was 120 mm. However, in Comparative Example 2, the plurality of diffused light control plates were arranged in a lattice shape in the direction along the longitudinal direction of the fluorescent lamp and in the orthogonal direction.

As a result of the above, Examples 1 to 4 were thin and formed with a good appearance, and even when looking up diagonally, it was not dazzling and could brighten the desk directly below. Moreover, since the surface was smooth, cleaning was easy.
On the other hand, in Comparative Examples 1 and 2, the diffused light control plate was formed thick (high), resulting in a 120 mm protrusion from the ceiling, causing a problem in appearance. In Comparative Example 2, since the diffused light control plate is in a lattice shape, the front and back surfaces are not smooth, and there is a problem in the ease of cleaning.

DESCRIPTION OF SYMBOLS 10 Illuminating device 11 Illuminating device main body 12 Light source 13 Cover 14 Cover main body 20 Optical film for illumination 21 Base material 22 Louver layer 23 Light transmission part 24 Between part

Claims (6)

An optical film for illumination used in an illumination device,
A substrate layer having translucency, and a louver layer formed on the substrate layer,
The louver layer is arranged at a predetermined interval along one surface of the base material layer, and a light transmission part formed of a resin that transmits light;
An intermediate portion formed between the light transmission portions and formed of a resin having a smaller refractive index than the light transmission portions;
An optical film for illumination, wherein at least one of the front and back surfaces is a smooth surface. An optical film for illumination used in an illumination device,
A substrate layer having translucency, and a louver layer formed on the substrate layer,
The louver layer is arranged at a predetermined interval along one surface of the base material layer, and a light transmission part formed of a resin that transmits light;
A portion formed between the light transmission portions and dispersed with a material that scatters light; and
An optical film for illumination, wherein at least one of the front and back surfaces is a smooth surface.   The optical film for illumination according to claim 1 or 2, wherein the light transmission part and the intermediate part extend along one direction of the surface of the base material layer, and are arranged in a direction different from the extending direction.   Two louver layers are laminated, and a direction in which the light transmission part and the intermediate part of one of the louver layers extends and a direction in which the light transmission part and the intermediate part of the other louver layer extend are viewed in plan view. The optical film for illumination according to any one of claims 1 to 3, which is orthogonal to each other. A lighting device body;
A light source disposed in the lighting device body;
The illumination optical film according to any one of claims 1 to 4, which is disposed in the illumination device main body so as to cover the light source.
Lighting device.   The lighting device according to claim 5, wherein the light source is a fluorescent lamp or a light emitting diode.

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