JP2018005113A - Optical sheet, lighting device and graphic display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sheet capable of emitting light from a light emission source of an organic electroluminescence to an observer with improved quality without generating a double image.SOLUTION: An optical sheet includes: a transparent base material layer 21; a plurality of light transmission parts 23 arranged at predetermined intervals on one side of the base material layer; and a light deflection parts 24 respectively arranged in the intervals of the plurality of light transmission parts with a resin packed, and configured to change a direction of incident light and emit the light.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical sheet disposed on a light output side of a light emitting layer by organic electroluminescence, an illumination device including the optical sheet, and an image display device.

  There is a technique of using an electrode as an image light source (image display device) or a white light source (illumination device) by providing an electrode on a light emitting layer by organic electroluminescence (hereinafter sometimes referred to as “organic EL”) to emit light. is there. Patent Documents 1 to 3 disclose techniques related to a device using an organic EL in this way.

  And in the apparatus using these organic EL, in order to improve the quality of the light radiate | emitted from the light emitting layer, the optical sheet is arrange | positioned at the observer side rather than the light emitting layer.

JP 2011-18583 A JP 2011-103237 A JP 2013-58447 A

  However, these optical sheets all have surface irregularities such as prisms, quadrangular pyramids, cones, and microlenses. Other films such as an antireflection film and a touch panel cannot be laminated on the optical sheet without an air interface, and there is a problem that a double image is generated.

  In view of the above problems, the present invention has an object to provide an optical sheet that can emit light from an organic electroluminescence light-emitting source to an observer with improved quality without generating a double image. To do. In addition, an illumination device and an image display device using the optical sheet are provided.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

  One aspect of the present invention is an optical sheet (20, 120, 220) disposed on the light output side of the organic electroluminescence laminate (10), which is a transparent substrate layer (21), and a substrate layer A plurality of light transmission parts (23) arranged at a predetermined interval on one surface of the light source and a resin filled in the intervals between the plurality of light transmission parts are arranged and emitted by changing the direction of the incident light And an optical deflection unit (24, 124, 224).

Here, when the angle formed by the diagonal line in the cross section of the transmission part and the sheet surface normal of the optical sheet is θ ₂ and the refractive index of the layer forming the light emitting surface of the organic electroluminescence laminate is n,
θ ₂ ≦ sin ⁻¹ (1 / n)
You may form so that.

  In addition, the light deflection unit can be configured to include a light scattering material.

  Further, the light deflection unit may be configured to have a light reflection layer at the interface with the light transmission unit.

  An illuminating device provided with the organic electroluminescent laminated body which radiate | emits white light, and the above-mentioned optical sheet arrange | positioned at the light emission side of an organic electroluminescent laminated body can be provided.

  Moreover, a video display apparatus provided with the organic electroluminescent laminated body which radiate | emits video light, and the above-mentioned optical sheet arrange | positioned at the light emission side of an organic electroluminescent laminated body can also be provided.

  According to the present invention, the optical sheet that enhances the quality of light from the organic EL light source has no irregularities on the surface, or the irregularities can be kept small, and the film that is laminated while improving the quality of light. Since no air layer is formed between them, the generation of a double image can be prevented.

It is a figure explaining a 1st form and is an exploded perspective view of the illuminating device. FIG. 3 is a cross-sectional view in the thickness direction of the lighting device 1. 2 is a cross-sectional view illustrating an optical sheet 20. FIG. 4A is a perspective view of the optical sheet 120, FIG. 4B is a cross-sectional view of the light control layer 22, and FIG. 4C is a cross-sectional view of the light control layer 122. It is sectional drawing explaining the optical sheet 220. FIG.

  The above-described operation and gain of the present invention will be clarified from the following embodiments of the invention. The present invention will be described below based on embodiments shown in the drawings. However, the present invention is not limited to the embodiment. Here, although the elements provided in the present invention are actually very fine and thin layers, they are shown deformed and enlarged in each figure for easy understanding. In addition, although elements are denoted by reference numerals, repeated reference numerals may be omitted for ease of viewing.

  FIG. 1 is a diagram for explaining the first embodiment, and is an exploded perspective view of the lighting device 1 including the optical sheet 20. In FIG. 1, for the sake of clarity, some layers are shown separately, but in reality, each layer is laminated through an adhesive layer or in direct contact. 2 is a cross-sectional view in the thickness direction including a line indicated by II-II in FIG.

The lighting device 1 includes an organic EL laminate 10, an optical sheet 20, and a circularly polarizing plate 30.
In this embodiment, the organic EL laminate 10 includes the substrate 11, the cathode layer 12, the electron transport layer 13, the light emitting layer 14, the hole transport layer 15, and the anode layer 16 in this order.
On the other hand, in this embodiment, the optical sheet 20 is laminated on the anode layer 16 of the organic EL laminate 10 and includes a base material layer 21 and a light control layer 22 from the anode layer 16 side.
Hereinafter, each layer will be described.

  The substrate 11 is a layer that becomes a substrate when the layers of the organic EL laminated body 10 are laminated, and is configured to have a strength and stiffness for functioning as a substrate, and a thickness and a material. Examples of the material include glass (soda lime glass, non-alkali glass, etc.) and resin (made of polyester resin, polyamide resin, epoxy resin, fluorine resin, etc.).

The cathode layer 12 is a layer that supplies electrons to the electron transport layer 13, and can be composed of a metal, an alloy, a metal oxide, or a material having a wide electrical conductivity, and preferably a material having a low work coefficient. . From this point of view, as the cathode layer, for example, alkali metal, alkali metal halide, alkali metal oxide, alkaline earth metal, and alloys of these with other metals, specifically sodium, sodium-potassium alloy, Examples thereof include lithium, magnesium, a magnesium-silver mixture, a magnesium-indium mixture, an aluminum-lithium alloy, and an Al / LiF mixture.
The cathode layer 12 can be laminated on the substrate 11 by a known method, and examples thereof include vapor deposition, chemical reaction, coating, and the like.
In this embodiment, since the cathode layer 12 is disposed on the opposite side of the light emitting layer 14 from the observer side, the cathode layer 12 can be made of a material having high reflectance. Thereby, the light emitted from the light emitting layer 14 can be reflected and provided toward the viewer.

  The electron transport layer 13 is a layer for receiving electrons from the cathode layer 12 and transporting them to the light emitting layer 14. As the electron transport 13 or the like, a known material used as an electron transport layer can be applied. Examples thereof include metal complexes such as Alq3 (tris (8-quinolinolato) aluminum), compounds having a heterocycle such as phenanthroline derivatives, pyridine derivatives, tetrazine derivatives, and oxadiazole derivatives.

  Note that the electron transport layer 13 may be provided on the cathode layer 12 side with an electron injection layer or a layer that inhibits the penetration of holes in order to increase the recombination rate.

  The light emitting layer 14 is a layer that emits light by generating excitons by recombination of the obtained electrons and holes by containing a predetermined organic compound material. A known material can be applied as the predetermined organic compound material. Examples include benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, perylene derivatives, perinone derivatives, oxadiazole derivatives. , Aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styrylamine derivatives, aromatic dimethylidin compounds, metal complexes of 8-quinolinol derivatives, Various metal complexes represented by rare earth complexes; polymerization of polythiophene, polyphenylene, polyphenylene vinylene, etc. Thing, and the like.

  The hole transport layer 15 is a layer for receiving holes from the anode layer 16 and transporting them to the light emitting layer 14. As the hole transport layer 15, a known material used as a hole transport layer can be applied. Examples thereof include a compound containing a carbazole group such as a carbazole derivative, a triarylamine compound, and an amine compound containing a fluorene derivative.

  The hole transport layer 15 may be provided with a hole injection layer on the anode layer 16 side or a layer that inhibits the penetration of electrons in order to increase the recombination rate.

The anode layer 16 is a layer that supplies holes to the hole transport layer 15. A known material that can be taken as the anode layer can be applied to the anode layer 16. This can include, for example, metals, alloys, metal oxides, or materials with a wide electrical conductivity, preferably materials with a high work coefficient. From this point of view, the anode layer includes metals such as gold, silver, chromium and nickel, metal oxides such as tin oxide, zinc oxide, indium oxide and indium tin oxide, copper iodide, copper sulfide, polyaniline, polythiophene and polypyrrole. And the like, and the like.
In this embodiment, since the anode layer 16 is disposed closer to the viewer than the light emitting layer 14, the anode layer 16 needs to be transparent. From this viewpoint, it is preferable to use indium tin oxide (ITO) as the anode layer 16. Thus, light can be appropriately transmitted through the anode layer 16.

  Here, the light emitted from the organic EL laminate 10 is white light in the present embodiment, and thus the lighting device 1 is obtained. However, the present invention is not limited to this, and image light accompanied by image information may be used. In this case, it functions as a video display device. What kind of light is emitted can be appropriately changed as necessary, and other constituent members provided for this purpose are known.

  The optical sheet 20 is a laminate that is laminated on the anode layer 16 side of the organic EL laminate 10 having the above-described configuration, and controls the light emitted from the organic EL laminate 10 to provide it to the observer side. In particular, the incident light can be efficiently emitted to the observer side. The optical sheet 20 of this embodiment includes a base material layer 21 and a light control layer 22.

In this embodiment, the base material layer 21 is a layer that is attached to the organic EL laminate 10 and that forms the light control layer 22 on the other surface. The base material layer 21 has translucency and supports the light control layer 22 so that deformation of the light control layer 22 can be prevented. From this viewpoint, as specific examples of the material constituting the base material layer 21, for example, a transparent resin mainly composed of acrylic, styrene, polycarbonate, polyethylene terephthalate (PET), acrylonitrile, triacetyl cellulose (TAC), epoxy acrylate, Examples thereof include urethane acrylate-based reactive resins (ionizing radiation curable resins and the like).
Among these, when the circularly polarizing plate 30 is used as in the present embodiment, a resin mainly composed of TAC, acrylic, or polycarbonate having a low birefringence (small retardation) is preferable. Furthermore, for applications that require high heat resistance such as in-vehicle applications, polycarbonate having a high glass transition point is desirable. Specifically, the glass transition point of polycarbonate is 143 ° C., which is generally suitable for in-vehicle applications that require durability at 105 ° C.

  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 thinner than this, wrinkles are likely to occur. Moreover, if the base material layer 21 is thicker than this, winding of the optical sheet 20 will become difficult.

  In this embodiment, the light control layer 22 is a layer that is laminated on the surface of the base material layer 21 that is opposite to the organic EL laminate 10. The light control layer 22 includes a light transmission part 23 that is substantially trapezoidal in the cross section in the thickness direction shown in FIG. 2, and a deflection part 24 that is disposed between adjacent light transmission parts 23. FIG. 3 shows an enlarged part of the optical sheet 20 in the cross section shown in FIG.

  The light transmission part 23 is a part whose main function is to transmit light. In the present embodiment, in the cross section shown in FIGS. 2 and 3, the bottom bottom is long on the base material layer 21 side (organic EL laminate 10 side). , An element having a substantially trapezoidal cross-sectional shape having a short upper base on the opposite side (observer side). The light transmissive portions 23 extend in the above-described direction while maintaining the cross section along the layer surface of the base material layer 21 and are arranged at a predetermined interval in a direction different from the extending direction. An interval having a substantially trapezoidal cross section is formed between the adjacent light transmission portions 23. Therefore, the interval has a long lower bottom on the upper base side (observer side) of the light transmission part 23, and on the lower bottom side (base material layer 21 side, organic EL laminate 10 side) of the light transmission part 23. It has a trapezoidal cross section with a short upper base, and the light deflection section 24 is formed by filling a necessary material described later. In this embodiment, the adjacent light transmission parts 23 are connected by the base part 22a on the long bottom side.

  The light transmission portion 23 has a refractive index of Nt. Such a light transmission part 23 can be formed by hardening the composition which comprises a transmission part. The value of the refractive index Nt is not particularly limited, but the refractive index is preferably 1.55 or more. However, since a material with a refractive index that is too high is likely to break, the refractive index is preferably 1.61 or less. More preferably, it is 1.56 or less.

As a material constituting the light transmitting portion 23, for example, a photocurable resin composition in which a reactive dilution monomer and a photopolymerization initiator are blended with a photocurable prepolymer is preferably used.
Examples of the photocurable prepolymer include epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polyester acrylate-based, and polythiol-based prepolymers.
Moreover, as a reactive dilution monomer, vinylpyrrolidone, 2-ethylhexyl acrylate, (beta) -hydroxy acrylate, tetrahydrofurfuryl acrylate etc. can be mentioned, for example. In addition, at least one of a vinyl compound having a fluorene skeleton, an acrylate compound having a fluorene skeleton, and a methacrylic acid ester compound having a fluorene skeleton can be used from the viewpoint of increasing the refractive index.
Examples of the photopolymerization initiator include hydroxybenzoyl compounds (2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, benzoin alkyl ether, etc.), benzoylformate compounds ( Methylbenzoylformate, etc.), thioxanthone compounds (isopropylthioxanthone, etc.), benzophenones (benzophenone, etc.), phosphate ester compounds (1,3,5-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenyl Phosphine oxide, etc.) and benzyldimethyl ketal.

The light deflecting unit 24 is a part that deflects the light that has reached here, and in this embodiment, the light deflecting unit 24 scatters the light that has arrived and deflects it so as to be emitted toward the viewer. Such a light deflection unit 24 can be formed, for example, by filling the recesses between the adjacent light transmission units 23 with the following materials. In this embodiment, examples of the material constituting the light deflection unit 24 include a composition in which a white pigment, a silver pigment, a transparent diffusing material, or the like is dispersed in a binder.
As a result, in the light control layer 22, no irregularities are formed in the light transmission part 23 and the light deflection part 24, and even if another film or the like is laminated on the light control layer 22, there is no air interface, and a double image is generated. Can be prevented.

  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.

  In the case of the transparent diffusing material, it can be constituted by mixing a transparent binder resin and a transparent diffusing agent having a different refractive index. Examples of the diffusing agent include crosslinked particles obtained by polymerizing monomers mainly composed of (meth) acrylic acid ester and styrene. As a specific example of the crosslinked particles, Ganzpearl manufactured by Aika Industry Co., Ltd. may be mentioned. The cross-linked particles can be controlled in refractive index by changing the mixing ratio of acrylic acid ester and styrene. For example, the refractive index can be made about 1.49 by increasing the acrylic ratio, and the refractive index can be made about 1.59 by increasing the styrene ratio. Also, urethane cross-linked particles can be used as the diffusing agent. Specific examples of the urethane crosslinked particles include Art Pearl manufactured by Negami Kogyo Co., Ltd. The diffusing agent can also be made into hollow particles.

On the other hand, the material constituting the binder for dispersing the white pigment, the silver pigment, and the transparent diffusing material is not particularly limited. For example, a reactive dilution monomer and a photopolymerization initiator are blended in a photocurable prepolymer. A photocurable resin composition is preferably used.
Examples of the photocurable prepolymer include urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and butadiene (meth) acrylate.
Moreover, as said reactive dilution monomer, (meth) acrylic acid ester monomer and (meth) acrylamide derivative are mentioned as a monofunctional monomer, for example. Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate. It is done.
Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one. 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, and the like.

  From the viewpoint of facilitating diffuse reflection of light at the interface between the light deflection unit 24 and the light transmission unit 23, the interface between the light transmission unit 23 and the light deflection unit 24 may be a matte surface.

  Thus, since the light deflection part 24 is formed in the recess between the adjacent light transmission parts 23, the shape thereof also follows the recess. Therefore, in this embodiment, the light deflection section 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 observer side, and has a side therebetween. This side forms an interface with the light transmission part 23 and becomes a common side.

In the light control layer 22 as described above, the angle θ ₁ formed by the interface between the light transmission part 23 and the light deflection part 24 and the sheet surface normal is preferably −20 degrees or more and 20 degrees or less. More preferably theta ₁ is less than 10 degrees 0 degrees. If θ ₁ is larger than 20 degrees or θ ₁ is smaller than −20 degrees, there is a possibility that the light transmittance is too low. Here, the theta ₁ is negative, short trapezoidal section of the light deflection unit 24 upper base observer side, a long lower base means that faces the organic EL laminate.

  The pitch at which the light transmission part 23 and the light deflection part 24 are arranged in parallel is not particularly limited, but is preferably 10 μm or more and 200 μm or less, and more preferably 30 μm or more and 100 μm or less. If the pitch of the light deflection units 24 is smaller than 10 μm, there is a possibility that a transmitted image becomes rainbow-like due to a diffraction phenomenon. In addition, if the pitch of the light deflection units 24 is too wide, it may be difficult to form the light deflection unit 24.

  The thickness of the light deflection unit 24 indicated by D in FIG. 3 is not particularly limited, but is preferably 20 μm or more and 300 μm or less. More preferably, they are 30 micrometers or more and 150 micrometers or less. If the light deflection unit 24 is too thin, it may be difficult to obtain a desired effect or it may be difficult to perform fine processing. Further, if the light deflecting portion 24 is too thick, there is a risk of causing problems in workability such as difficulty in releasing from the mold during manufacturing.

Further, as indicated by θ ₂ in FIG. 3, when the angle formed by the diagonal line of the light transmission portion 23 in the cross section and the normal to the sheet surface is the expected angle θ ₂ , the expected angle θ ₂ is the organic EL laminate. The total reflection critical angle is preferably equal to or less than the critical angle at the interface where 10 and the optical sheet 20 are in contact (in this embodiment, the interface between the anode layer 16 and the base material layer 21). As a result, all the light incident on the light transmission part at a large angle with respect to the normal to the sheet surface also reaches the deflecting part 24, and the amount of light that can be scattered and emitted can be increased. .
More preferably, the refractive index of the layer (the anode layer 16 in this embodiment) on which the optical sheet 20 is laminated is a layer constituting the light exit surface of the organic EL laminate 10 in the organic EL laminate 10. When
θ ₂ ≦ sin ⁻¹ (1 / n)
It is.

Furthermore, a refractive index difference may be provided between the light transmission part 23 and the light deflection part 24. By setting the light transmitting portion 23 to have a higher refractive index than that of the light deflecting portion 24, a part of the light can be totally reflected at the interface between the light transmitting portion 23 and the light deflecting portion 24. It becomes light that can be provided to the observer by changing.
In the case of providing the difference in refractive index, the value of the refractive index Nr is not particularly limited, but is preferably 1.50 or less from the viewpoint of appropriately performing the total reflection, and among these, from the viewpoint of availability. .47 or more is preferable. More preferably, it is 1.49 or more. In this case, the difference in refractive index between the refractive index Nt of the light transmitting portion 23 and the refractive index Nr of the light absorbing portion 24 is not particularly limited, but is preferably 0.05 or more and 0.14 or less. . By increasing the refractive index difference, more light can be totally reflected.

In this embodiment, an example in which the interface between the light transmitting portion 23 and the light deflecting portion 24 is straight in the cross section is shown. However, the present invention is not limited thereto, and may be a polygonal line shape, a convex curved surface shape, a concave curved surface shape, etc. Also good. Moreover, the cross-sectional shape may be the same in the some light transmissive part 23 and the light deflection | deviation part 24, and a different cross-sectional shape may have predetermined regularity.
According to these forms, it is possible to control the scattering, total reflection, and refraction of light in a desired manner as necessary.

The optical sheet 20 as described above can be manufactured, for example, as follows.
First, the light transmission part 23 of the light control layer 22 is formed by a method using a mold roll. That is, a mold roll is prepared in which irregularities capable of transferring the shape of the light transmitting portion 23 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 the one side of a base material, and a mold roll. 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.

  Appropriate curing such as irradiating light from the substrate side with a light irradiation device to the composition before curing constituting the light transmitting portion 23 sandwiched between the mold roll and the substrate. Cured by the method. Thereby, the shape of the light transmission part 23 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 light deflecting portion 24 can be formed by filling the concave portion formed between the adjacent light transmitting portions 23 with the uncured composition constituting the light deflecting portion 24 and curing it. Specifically, the composition before the curing that constitutes the light deflection unit 24 is excessively supplied to the recesses between the adjacent light transmission units 23, and the amount is adjusted by scraping off the excess with a blade. The recess is filled with the composition. Then, the composition filled in the recess is cured by an appropriate method.
In this manner, the light control layer 22 having no unevenness or unevenness on the base material layer 21 can be formed, and the optical sheet 20 is obtained.

  Returning to FIGS. 1 to 3, the circularly polarizing plate 30 will be described. The circularly polarizing plate 30 is a known member, but is a member in which a polarizing member and a retardation member are laminated. Since the reflected light of the light once transmitted through the circularly polarizing plate is polarized and cannot be absorbed and transmitted by the polarizing member of the circularly polarizing plate, the external light is not emitted to the observer side, The influence can be reduced.

  The illuminating device 1 configured as described above includes the organic EL laminate 10, the optical sheet 20, and the circularly polarizing plate 30 in a housing (not shown), and is arranged so that the circularly polarizing plate 30 side is an observer side. By doing so, it can be set as the illuminating device by organic EL. In that case, an electric circuit, a power supply circuit, etc. for operating the illuminating device 1 are also provided as needed. Here, even if the circularly polarizing plate 30 is laminated on the optical sheet 20, the light control layer 22 of the optical sheet 20 is not uneven as described above, or the unevenness is reduced, so that an air interface is not formed. Generation of a double image can be prevented.

  A display device provided with such a lighting device 1 operates as follows, for example. Here, an example in which white light is emitted from the organic EL laminate 10 will be described. However, the light is not necessarily white light, and may be light including video information. FIG. 3 shows an example of the optical path. However, this optical path example is conceptual and does not strictly represent scattering, reflection, and refraction.

  When the display device is operated, light is emitted from the organic EL laminate 10. Light emitted from the organic EL laminate 10 passes through the base material layer 21 and enters the light control layer 22. At this time, since the optical sheet 20 is laminated on the light output side of the organic EL laminate 10, the refractive index difference at this interface becomes smaller than that at the air interface, and the light enters the optical sheet 20 without being totally reflected. You can increase the amount of light. That is, light incident on the interface at a large angle with respect to the normal to the sheet surface can also transmit through the interface between the organic EL laminate 10 and the optical sheet 20, and provide more light to the viewer. Is possible.

An example of the optical path of the light incident on the light control layer 22 is shown in FIG. 3 as light L _{1 to} L ₄ .
The lights L ₁ and L ₂ are incident on the light control layer 22 substantially parallel to the thickness direction of the light control layer 22. Then, the light L ₁ is transmitted through the light transmitting portion 23, and the light L ₂ is incident on the light deflecting portion 24. The light incident on the light deflection unit 24 is scattered, and the viewing angle is widened and emitted to the viewer side.
On the other hand, the image light L ₃ enters the light control layer 22 obliquely with respect to the thickness direction and reaches the light deflecting unit 24. As a result, the light is scattered, and is emitted to the viewer side so as to include light at an angle that can be observed by the viewer. Therefore, the light incident on the optical sheet 20 at a large angle that cannot be observed by the observer is provided as light that can be observed by the observer, and the amount of light that can be provided to the observer can be increased.

When the refractive index of the light transmitting portion 23 is larger than the refractive index of the light deflecting portion 24, the following total reflection is also possible. That is, the light L ₄ enters the light deflecting unit 24 obliquely with respect to the thickness direction, and reaches the interface between the light transmitting unit 23 and the light deflecting unit 24 at an angle greater than the total reflection critical angle. As a result, the light is totally reflected and travels in a direction different from the incident direction. Such light may also have the effect of increasing the amount of light that can be provided to the observer.

  In the optical sheet 20 described here, the base material layer 21 is the organic EL laminate 10 side and the light control layer 22 is laminated on the observer side. Alternatively, the light control layer 22 may be disposed and the base material layer 21 may be disposed on the viewer side.

FIG. 4 shows a diagram for explaining the second embodiment. The second embodiment is different from the first embodiment in that an optical sheet 120 is used instead of the optical sheet 20. About another structure, it is the same as that of a 1st form.
4A is a perspective view of the optical sheet 120, FIG. 4B is a sectional view in the thickness direction of the optical sheet 120 along the line indicated by IVb-IVb in FIG. 4A, and FIG. FIG. 4 is a cross-sectional view in the thickness direction of the optical sheet 120 taken along the line indicated by IVc-IVc in FIG.

  The optical sheet 120 is different from the optical sheet 20 in that another light control layer 122 is further laminated on the light control layer 22. That is, another light control layer 122 is laminated on the surface of the light control layer 22 opposite to the side on which the base material layer 21 is disposed. The base material layer 21 and the light control layer 22 are as described above.

The other light control layer 122 includes a light transmission part 123 that is substantially trapezoidal in the cross section in the thickness direction shown in FIG. 4C, and a light deflection part 124 that is disposed between adjacent light transmission parts 123. Yes. The light transmission unit 123 is the same as the light transmission unit 23, and the light deflection unit 124 is the same as the light deflection unit 24.
However, as can be seen from FIG. 4A, the direction in which the light transmitting portion 123 and the light deflecting portion 124 extend and the direction in which the light transmitting portion 23 and the light deflecting portion 24 extend are 90 ° in the front view of the optical sheet 120. Arranged differently. This further increases the amount of light that can be provided to the observer.

FIG. 5 shows a diagram for explaining the third embodiment. The third embodiment is different from the first embodiment in that an optical sheet 220 is used instead of the optical sheet 20. About another structure, it is the same as that of a 1st form, and the optical sheet 220 is demonstrated here.
The optical sheet 220 includes the base material layer 21 and the light control layer 222. The base material layer 21 is the same as the base material layer 21 described in the optical sheet 20.

  In the light control layer 222, the light deflection unit 224 disposed between the adjacent light transmission units 23 has a light reflection layer 224 a at the interface with the light transmission unit 23. A transparent portion 224b that is transparent while being sandwiched between the light reflecting layers 224a of the light deflection portion 224 is formed.

The light reflecting layer 224a is a layer for reflecting light using reflection from a metal surface or other material surface, and is formed at the interface with the light transmitting portion 23 in the light deflecting portion 224. The light reflecting layer 224a can be formed of a deposited film of aluminum, copper, silver, or the like, for example.
The transparent part 224b may be formed so as to be filled with a transparent resin.

According to such a light control layer 222, for example, light indicated by L ₁₀ in FIG. 5 is transmitted through the light transmitting portion 23 without reaching the interface between the light transmitting portion 23 and the light deflection unit 224. Alternatively, the light indicated by L ₁₁ in FIG. 5 can be reflected by the light reflecting layer 224 a even when reaching the interface between the light transmitting portion 23 and the light deflecting portion 224, and is reflected and transmitted through the light transmitting portion 23. Even in this mode, the amount of light that can be provided to the observer by controlling the light to be emitted to the observer can be increased.

  In this example, an optical sheet was manufactured following the example of the optical sheet 20, and an optical sheet of a comparative example in which the optical sheets were not stacked was manufactured and evaluated. Details are as follows.

Example 1
<Base material layer>
・ Material, thickness: polycarbonate resin, thickness 130μm
<Light control layer>
・ Pitch: 39 μm (P _{k in} FIG. 3)
-Upper width of light deflection part: 4 μm (W _{a in} FIG. 3)
The bottom width of the light deflection unit: 10 μm (W _{b in} FIG. 3)
-Thickness of the light deflection unit: 36 μm (D in FIG. 3)
-Light control layer thickness: 61 μm
-Material and refractive index of light transmission part: UV curable urethane acrylate, refractive index 1.56
-Material and refractive index of light deflector: Acrylic beads (Aika Industry Co., Ltd., Gantz Pearl (registered trademark)) 25% by mass dispersed in UV curable urethane acrylate having a refractive index of 1.49.-Light transmissive part and light deflector Tilt angle of interface with 4.8 ° (θ _{1 in} FIG. 3)
-Expected angle: 41.9 ° (θ _{2 in} FIG. 3)

(Example 2)
The following points were changed from Example 1 in the light control layer.
-Thickness of the light deflection unit: 102 μm (D in FIG. 3)
-Light control layer thickness: 127 μm
Inclination angle of the interface between the light transmitting part and the light deflecting part: 1.7 ° (θ _{1 in} FIG. 3)
-Expected angle: 17.4 ° (θ _{2 in} FIG. 3)

(Example 3)
The following points were changed from Example 1 in the light control layer.
-Material and refractive index of light deflecting part: UV curable urethane acrylate containing 5% aluminum flakes

Example 4
The following points were changed from Example 2 in the light control layer.
-Material and refractive index of light deflecting part: UV curable urethane acrylate containing 5% aluminum flakes

The optical sheet according to each of the above examples was laminated on the light emission side of an organic EL laminate (Toshiba Corporation, REGZA TABLET (registered trademark), AT570).
As a comparative example, the organic EL laminate was evaluated as it was.

  For each example, the organic EL laminate was turned on, and the brightness of the screen was visually evaluated while moving obliquely with respect to the front and front of the screen (changing the viewing angle). As a result, in Examples 1 to 4, bright light could be observed at any position where the viewing angle was changed compared to the comparative example.

DESCRIPTION OF SYMBOLS 1 Illuminating device 10 Organic EL laminated body 11 Substrate 12 Cathode layer 13 Electron transport layer 14 Light emitting layer 15 Hole transport layer 16 Anode layer 20, 120, 220 Optical sheet 21 Base material layer 22 Light control layer 23 Light transmission part 24 Light deflection Part 30 circularly polarizing plate 122 light control layer (other light control layer)
124 Light deflection unit 222 Light control layer 224 Light deflection unit 224a Light reflection layer 224b Transparent portion

Claims (6)

An optical sheet disposed on the light output side of the organic electroluminescence laminate,
A substrate layer that is transparent;
A plurality of light transmission parts arranged at a predetermined interval on one surface of the base material layer;
A light deflecting unit that is arranged with resin filled in the interval between the plurality of light transmitting units, and changes the direction of the incident light and emits the light; and
An optical sheet comprising: When the angle formed by the diagonal line in the cross section of the transmission part and the sheet surface normal of the optical sheet is θ ₂ and the refractive index of the layer forming the light emitting surface of the organic electroluminescence laminate is n,
θ ₂ ≦ sin ⁻¹ (1 / n)
The optical sheet according to claim 1, wherein:   The optical sheet according to claim 1, wherein the light deflection section includes a light scattering material.   The optical sheet according to claim 1, wherein the light deflection unit includes a light reflection layer at an interface with the light transmission unit. An organic electroluminescence laminate that emits white light; and
An illuminating device comprising: the optical sheet according to any one of claims 1 to 4, which is disposed on a light output side of the organic electroluminescence laminate. An organic electroluminescence laminate that emits image light;
An image display apparatus comprising: the optical sheet according to claim 1 disposed on a light output side of the organic electroluminescence laminate.

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