JP2016122661A - Organic electroluminescent device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent device excellent in the external extraction efficiency of emission light and capable of achieving reduced power consumption and a prolonged life.SOLUTION: An organic electroluminescent device includes at least a reflecting electrode 6, an organic electroluminescent layer 2, a transparent substrate 4 and a light extraction layer 5, in the order. The ratio (w/d) between the total average thickness d of a layer and a member, which are present between the reflecting electrode and the light extraction layer, and the minimum width w in a non-light emitting region protruding from an outer peripheral edge of an effective light emitting region in the organic electroluminescent layer is 9 or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an organic electroluminescence device (sometimes referred to as “organic EL device” or “organic electroluminescence device”).

  The organic electroluminescent device is a self-luminous display device and is expected to be used for displays and illumination. For example, an organic electroluminescent display has advantages in display performance such as higher visibility than conventional CRTs and LCDs and no viewing angle dependency. In addition, there is an advantage that the display can be made lighter and thinner. On the other hand, in addition to the advantages that organic electroluminescence lighting can be reduced in weight and thickness, it has the potential to realize illumination in a shape that could not be realized by using a flexible substrate. Yes.

  The organic electroluminescent layer in the organic electroluminescent device has a laminated structure including a light emitting layer, a transparent electrode, and other layers. For this reason, emitted light having a critical angle or more determined by the refractive index of the light emitting layer and the refractive index of the emission medium cannot be taken out to the air, and is totally reflected and confined inside the organic electroluminescent layer, resulting in a loss. In the calculation based on Snell's law of classical refraction, it is assumed that the refractive index n of the light emitting layer is 1.8 (according to Non-Patent Document 1, the refractive index n of the light emitting layer is 1.7 to 1.85). When the light distribution of the light emitted from the layer is Lambertian, the light extraction efficiency up to the air is only about 30% due to the difference between the refractive index of the light emitting layer and the refractive index of air. There is a problem that 70% of light is confined inside the organic electroluminescent layer due to the difference in refractive index and cannot be emitted to the air.

In order to solve the above problem and improve the light extraction efficiency, it is necessary to prevent the reflection due to the difference in refractive index between the light emitting layer and the air, particularly the occurrence of total reflection. The fine particle layer is one of the effective methods for preventing the occurrence of total reflection, and various proposals have been made to change the angle of light emitted from the light emitting layer by providing the fine particle layer.
For example, Patent Document 1 proposes an organic EL device made of a transparent material or opaque particles in which light scattering portions are dispersed or aggregated on a single plane. However, in this proposal, the refractive index of the polymer in the fine particle layer is not specified, and if it is smaller than the refractive index of the light emitting layer, total reflection occurs and light emitted from the light emitting layer cannot enter the fine particle layer. Therefore, it is insufficient for improving the light extraction efficiency.
Patent Document 2 and Patent Document 3 describe increasing the refractive index of the polymer in the fine particle layer. However, in these proposals, since the fine particle layer is between the transparent substrate and the light emitting layer, the light radiated from the fine particle layer is incident on the transparent substrate, and there is a difference in refractive index between the transparent substrate and the air. There are many components that are totally reflected and returned in the organic electroluminescence device. Although there is a component that can be reflected and extracted again by the reflective electrode, the optical path length of the light reflected by the transparent substrate becomes longer, and the component that becomes a loss due to the finite size of the organic electroluminescent element and absorption of the light emitting layer increases. It is insufficient to improve the extraction efficiency.
Patent Document 4 proposes an organic electroluminescence element having a high refractive index substrate and a fine particle layer on the light extraction surface. In Patent Document 4, a reflective electrode made of MgAg is used. However, in this proposal, there is a component in which light emitted from the organic electroluminescent layer is scattered by the fine particle layer and radiated to the air, and another component is reflected in the organic electroluminescent layer by backscattering. Taking out the component reflected by this backscattering is affected by the reflectance of the reflective electrode, but the reflective electrode made of MgAg has a problem that the reflectance is inferior to that of the reflective electrode made of Ag. In addition, since the light emitted from the organic electroluminescent layer is at all angles, when it travels in the thickness direction and is reflected, scattered, or totally reflected, it collides with the wall surface of the organic electroluminescent layer, resulting in loss. There is a problem of end.

JP-A-8-83688 JP 2004-127842 A JP 2004-303724 A JP 2004-296429 A

PIONEER R & D Vol. 11 No. 1, pp21-28

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide an organic electroluminescent device that is excellent in external extraction efficiency of emitted light, and can achieve low power consumption and long life.

As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, a high refractive index polymer and a fine particle layer containing fine particles having a refractive index different from that of the polymer are formed into an organic electroluminescence of a high refractive index transparent substrate. The reflective electrode is made of metal Ag, disposed on the opposite side of the layer, and the total average thickness d of layers and members existing between the reflective electrode and the light extraction layer, and the effective light emitting region of the organic electroluminescent layer The ratio (w / d) to the minimum width w in the non-light emitting region protruding from the outer peripheral edge of the organic electroluminescent layer is 9 or more, that is, the surface area of the effective light emitting region in the organic electroluminescent layer is made smaller than the surface area of the other layers As a result, it was found that the light extraction efficiency can be greatly improved.
Here, the high refractive index in the high refractive index polymer and the high refractive index transparent substrate means that it is equivalent to the refractive index (refractive index 1.8) of the organic electroluminescent layer.

Means for solving the problems are as follows. That is,
<1> An organic electroluminescent device comprising at least a reflective electrode, an organic electroluminescent layer, a transparent substrate, and a light extraction layer in this order,
A ratio between the total average thickness d of the layers and members existing between the reflective electrode and the light extraction layer and the minimum width w in the non-light emitting region protruding from the outer peripheral edge of the effective light emitting region of the organic electroluminescent layer ( The organic electroluminescent device is characterized in that w / d) is 9 or more.
<2> The organic electroluminescent device according to <1>, wherein the total average thickness d of the layers and members existing between the reflective electrode and the light extraction layer is the total average thickness of the organic electroluminescent layer and the transparent substrate. is there.
<3> The organic electroluminescent device according to any one of <1> to <2>, wherein light emitted from the organic electroluminescent layer is emitted from the light extraction layer.
<4> The organic electroluminescent device according to any one of <1> to <3>, wherein the reflective electrode is made of Ag.
<5> The organic electroluminescent device according to any one of <1> to <4>, wherein the transparent substrate has a refractive index equal to or higher than that of the organic electroluminescent layer.
<6> The organic electroluminescent device according to <5>, wherein the refractive index of the transparent substrate is the same as the refractive index of the organic electroluminescent layer.
<7> The organic electroluminescence device according to any one of <1> to <6>, wherein the light extraction layer is a fine particle layer containing a polymer and fine particles.
<8> The organic electroluminescence device according to <7>, wherein the refractive index of the polymer in the fine particle layer is different from the refractive index of the fine particles.
<9> The organic electroluminescent device according to any one of <7> to <8>, wherein the polymer in the fine particle layer has the same refractive index as that of the transparent substrate.
<10> The organic electroluminescence device according to any one of <7> to <9>, wherein an average particle size of the fine particles is 0.5 μm to 10 μm.
<11> The organic electroluminescence device according to any one of <7> to <10>, wherein the volume filling rate of the fine particles in the fine particle layer is 20% to 70%.
<12> The organic electroluminescent device according to any one of <7> to <11>, wherein the fine particle layer has an average thickness of 5 μm to 200 μm.
<13> From the above <7>, wherein the average particle diameter of the fine particles is 0.5 μm to 6 μm, the volume filling ratio of the fine particles in the fine particle layer is 20% to 70%, and the average thickness of the fine particle layer is 50 μm or less. <12> The organic electroluminescence device according to any one of <12>.

  ADVANTAGE OF THE INVENTION According to this invention, the said various conventional problems can be solved, the organic electroluminescent apparatus which is excellent in the external extraction efficiency of emitted light, and can aim at low power consumption and long life can be provided.

FIG. 1 is a schematic diagram illustrating a simulation model used in the simulation 1 of the first embodiment. FIG. 2 is a graph showing the relationship between the ratio (w / d) and the light extraction efficiency for the Ag reflective electrode, the MgAg reflective electrode, and the Al reflective electrode. FIG. 3 is an enlarged view of part A in FIG. FIG. 4 is a diagram showing the result of normalizing the light extraction efficiency shown in FIG. FIG. 5 is a schematic diagram illustrating a simulation model without a fine particle layer used in the simulation 2 of the second embodiment. FIG. 6 is a schematic diagram illustrating a simulation model having a fine particle layer used in the simulation 2 of the second embodiment. FIG. 7 shows the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are changed to 1.5, 1.8, and 2.0. It is the shown graph. FIG. 8 shows the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are changed to 1.5, 1.8, and 2.0. It is the shown graph. FIG. 9 shows the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are changed to 1.5, 1.8, and 2.0. It is the shown graph. FIG. 10 is a graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when changed to an Ag reflective electrode, an AgMg reflective electrode, and an Al reflective electrode. FIG. 11 is a graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the volume filling rate of the fine particles is changed to 10%, 20%, 30%, 50%, and 70%. FIG. 12 is a graph showing a relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the volume filling rate of the fine particles is changed to 10%, 20%, 30%, 50%, and 70%. FIG. 13 is a graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the average particle size of the fine particles is changed to 0.5 μm, 1 μm, 2 μm, 6 μm, and 10 μm. FIG. 14 is a graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the average particle size of the fine particles is changed to 0.5 μm, 1 μm, 2 μm, 6 μm, and 10 μm. FIG. 15 is a graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the average particle size of the fine particles is changed to 0.5 μm, 1 μm, 2 μm, 6 μm, and 10 μm. FIG. 16 is an enlarged view of FIG. FIG. 17 is a schematic view showing an example of the organic electroluminescent device of the present invention.

  The organic electroluminescent device of the present invention includes at least a reflective electrode, an organic electroluminescent layer, a transparent substrate, and a light extraction layer in this order, and further includes other members as necessary.

The organic electroluminescent device is preferably a bottom emission type in which light emitted from the organic electroluminescent layer is emitted from the light extraction layer. In the case of the top emission type, since light emitted from the organic electroluminescent layer must be transmitted, it is necessary to be transparent in the visible region (wavelength region of 400 nm to 700 nm). In the case of the bottom emission type, it is not necessary to be particularly transparent, but the organic compound is a silicone polymer, epoxy polymer, acrylic polymer, urethane polymer, etc .; the inorganic compound is SiNx, SiON, SiO ₂ , Al ₂ O ₃ A TiO ₂ layer can be widely used, and the bottom emission type is preferable in terms of material selectivity and cost in forming an element.

In the present invention, the total average thickness d of the layers and members existing between the reflective electrode and the light extraction layer, and the minimum width in the non-light-emitting region protruding from the outer peripheral edge of the effective light-emitting region of the organic electroluminescent layer The ratio (w / d) to w is 9 or more, preferably 20 or more, and more preferably 40 or more in terms of convergence of light extraction efficiency and higher light extraction efficiency. Thus, the light extraction efficiency is improved by setting the ratio (w / d) to 9 or more, that is, by configuring the surface area of the effective light emitting region in the organic electroluminescent layer to be smaller than the surface area of the other layers. Can do. If the ratio (w / d) is less than 9, it may be lower than 0.8 times the maximum light extraction efficiency, and sufficient light extraction efficiency may not be obtained.
The total average thickness d of the layers and members existing between the reflective electrode and the light extraction layer represents the distance between the reflective electrode and the light extraction layer, and is the total average thickness of the organic electroluminescent layer and the transparent substrate. It is preferable that
Here, the effective light emitting region of the organic electroluminescent layer means a region that actually emits light in the organic electroluminescent layer.
Examples of the layer and member existing between the reflective electrode and the light extraction layer include organic electroluminescent layers, other layers such as a transparent substrate, and other members. The transparent electrode is included in the organic electroluminescent layer.
The total average thickness d of the layers and members existing between the reflective electrode and the light extraction layer is preferably 70 μm to 2,000 μm, and more preferably 200 μm to 1,000 μm.
The minimum width w in the non-light emitting region that protrudes from the outer peripheral edge of the effective light emitting region of the organic electroluminescent layer is preferably 0.5 mm to 50 mm, and more preferably 2 mm to 30 mm.

<Reflective electrode>
The reflective electrode is an electrode disposed on the side opposite to the light extraction side, and the reflective electrode has a function of reflecting light emitted from the organic electroluminescent layer.
As the material of the reflective electrode, silver (Ag) is preferably used from the viewpoint of reflectance. If a metal other than silver (Ag), such as MgAg or Al, is used for the reflective electrode, the light extraction efficiency may not be improved. In the case where the reflective electrode is made of silver (Ag), a layer in which an Al or LiF layer of an optically negligible level (10 nm or less) is added between the electron transport layers in order to improve electrical characteristics is also included.
For example, a method such as a vacuum evaporation method, an electron beam method, a sputtering method, a resistance heating evaporation method, or a coating method is used to form the reflective electrode.
The thickness of the reflective electrode is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 nm to 5 μm, more preferably 50 nm to 1 μm, and still more preferably 100 nm to 1 μm.

<Transparent substrate>
The refractive index of the transparent substrate is preferably equal to or higher than the refractive index of the organic electroluminescent layer. When the refractive index of the transparent substrate is higher than the refractive index of the organic electroluminescent layer, when light emitted from the organic electroluminescent layer is emitted to the transparent substrate, light is reflected between the reflective electrodes and the transparent substrate. The component absorbed by the organic electroluminescent layer and the reflective electrode is lost during the reciprocation of the light, causing the light extraction efficiency to decrease. Further, if the refractive index of the transparent substrate is increased, total reflection occurs between the transparent substrate and the fine particle layer unless the refractive index of the polymer of the fine particle layer is increased equally, and light cannot be extracted. When the refractive index of the polymer of the fine particle layer is set to a high refractive index, the difference in refractive index between the transparent substrate and air or between the fine particle layer and air increases so that the backscattered light increases and the light is reflected from the fine particle layer. More components are absorbed while reciprocating between the electrodes, which causes a reduction in light extraction efficiency. Further, the transparent substrate having a refractive index of 1.95 or more and the polymer of the fine particle layer are more expensive and more preferable to have the same refractive index as that of the organic electroluminescent layer from the viewpoint of complicated production.
The refractive index of the transparent substrate is preferably equal to the refractive index of the polymer in the fine particle layer from the viewpoint of eliminating interlayer reflection and total reflection.
The refractive index of the transparent substrate varies depending on the material used and cannot be defined unconditionally. For example, in the case of glass, it is preferably 1.55 to 1.95.

  The transparent substrate may be appropriately selected in shape, structure, size, etc. In general, the substrate is preferably plate-shaped. The structure of the transparent substrate may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members. Good. The transparent substrate may be colorless and transparent or colored and transparent, but is preferably colorless and transparent in that it does not scatter or attenuate light emitted from the organic electroluminescent layer.

  The material for the substrate is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include inorganic materials such as yttria-stabilized zirconia (YSZ) and glass; polyethylene terephthalate resin, polybutylene phthalate resin, polyethylene naphthalate. Examples thereof include polyester resins such as resins, organic materials such as polystyrene resins, polycarbonate resins, polyethersulfone resins, polyarylate resins, polyimide resins, polycycloolefin resins, norbornene resins, and poly (chlorotrifluoroethylene) resins. These may be used individually by 1 type and may use 2 or more types together.

  When glass is used as the substrate, it is preferable to use non-alkali glass as the material in order to reduce ions eluted from the glass. Moreover, when using soda-lime glass, it is preferable to use what gave barrier coats, such as a silica (for example, barrier film board | substrate). In the case of an organic material, it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability.

When the thermoplastic substrate is used, a hard coat layer, an undercoat layer, or the like may be further provided as necessary.
Among these, transparent synthetic resins such as transparent glass, quartz, sapphire, or polyester, polyacrylate, polycarbonate, polyetherketone are particularly preferable.

  The thickness of the transparent substrate is not particularly limited as long as it is sufficient to maintain mechanical strength, and can be appropriately selected according to the purpose. However, when glass is used, 0.2 mm or more is preferable, and 0 More preferably, it is 7 mm or more.

<Light extraction layer>
The light extraction layer is preferably a fine particle layer.
The fine particle layer contains at least a polymer and fine particles, and further contains other components as necessary.

The refractive index of the polymer in the fine particle layer is preferably different from the refractive index of the fine particles. When fine particles with a refractive index different from the refractive index of the polymer exist in the polymer having a refractive index equivalent to the refractive index of the transparent substrate, every time the light emitted from the organic electroluminescent layer hits the polymer, the polymer and Because the light is scattered and the radiation angle of the light is converted due to the difference in refractive index between the fine particles, when the light with a high radiation angle that is originally totally reflected is converted into a low radiation angle, the light is converted into a fine particle layer (or transparent). From the substrate) to the air. In addition, the light having a high radiation angle is scattered in the direction of the reflective electrode, and when reflected by the reflective electrode, it is emitted again to the fine particle layer, and the radiation angle is converted. It is preferable in that it can improve the light extraction efficiency of the organic electroluminescent device.
As described above, the refractive index of the polymer in the fine particle layer is preferably equal to the refractive index of the transparent substrate.

-Fine particles-
The fine particles are not particularly limited as long as the refractive index is different from the refractive index of the polymer of the fine particle layer, and can scatter light, and can be appropriately selected according to the purpose. It may be inorganic fine particles, and preferably contains two or more fine particles.

Examples of the organic fine particles include polymethyl methacrylate beads, acrylic-styrene copolymer beads, melamine beads, polycarbonate beads, polystyrene beads, crosslinked polystyrene beads, polyvinyl chloride beads, benzoguanamine-melamine formaldehyde beads, and the like.
Examples of the inorganic fine particles include _{ZrO 2, TiO 2, Al 2} O 3, In 2 O 3, ZnO, SnO 2, Sb 2 O 3, and the like. Among these, TiO ₂ , ZrO ₂ , ZnO, and SnO ₂ are particularly preferable.

The refractive index of the fine particles is not particularly limited as long as it is different from the refractive index of the polymer of the fine particle layer, and can be appropriately selected according to the purpose, but is preferably 1.55 to 2.6. 1.58 to 2.1 is more preferable.
The refractive index of the fine particles is determined by measuring the refractive index of the refractive liquid using, for example, an automatic refractive index measuring device (KPR-2000, manufactured by Shimadzu Corporation), and then a precision spectrometer (GMR-1DA, Shimadzu Corporation). ) And can be measured by the Shribsky method.
The average particle diameter of the fine particles is preferably 0.5 μm to 10 μm, and more preferably 0.5 μm to 6 μm. When the average particle diameter of the fine particles exceeds 10 μm, most of the light is forward scattered, and the ability to convert the angle of light by the scattered fine particles may be reduced. In addition, as described above, light having a high emission angle returns to the organic electroluminescent layer, is reflected by the reflective electrode, and re-radiates again to the fine particle layer. However, the size of the organic electroluminescent device is limited, and the organic electroluminescent layer and the reflective layer are reflected. The light extraction efficiency may decrease due to the absorption of the electrode. On the other hand, if the average particle size of the fine particles is less than 0.5 μm, the wavelength becomes smaller than the wavelength of visible light, Mie scattering changes to the Rayleigh scattering region, the wavelength dependency of the scattering efficiency of the fine particles increases, and light emission It is expected that the chromaticity of the element will change greatly and the light extraction efficiency will decrease.
The average particle diameter of the fine particles can be measured, for example, by an apparatus using a dynamic light scattering method such as Nanotrack UPA-EX150 manufactured by Nikkiso Co., Ltd., or by image processing of an electron micrograph.

The volume filling rate of the fine particles in the fine particle layer is preferably 20% to 70%, and more preferably 30% to 65%. If the volume filling factor is less than 20%, the probability that light incident on the fine particle layer is scattered by the fine particles is small, and the ability to convert the light angle of the fine particle layer is small. If it is not thickened, the light extraction efficiency may decrease. Further, increasing the thickness of the fine particle layer may lead to an increase in cost. Furthermore, the light extraction efficiency may decrease due to increased backscattering. On the other hand, if the volume filling rate exceeds 70%, it may be close to close packing, and the characteristics of the fine particle layer may be difficult to control.
The volume filling rate of the fine particles in the fine particle layer can be measured, for example, by a gravimetric method. First, the specific gravity of particles is measured with a particle specific gravity measuring device (MARK3, manufactured by Union Engineering Co., Ltd.), and the weight of fine particles is measured with an electronic balance (FZ-3000i, manufactured by A & D). Next, a part of the produced fine particle layer is cut off, and the thickness of the fine particle layer is measured with a scanning electron microscope (S-3400N, manufactured by Hitachi High-Tech Co., Ltd.) to obtain the volume filling rate of the fine particles in the fine particle layer. it can.

<< Polymer >>
As described above, the refractive index of the polymer in the fine particle layer is equivalent to the refractive index of the transparent substrate, and is preferably 1.55 to 1.95.
As such a high refractive index polymer, a high refractive index composition in which the polymer is adjusted to a high refractive index with small refractive index fine particles is preferably used.
The high refractive index composition contains the fine particles, small refractive index fine particles, and a matrix, and further contains a dispersant, a solvent, and other components as necessary.

-High refractive index fine particles-
The high refractive index fine particles preferably have a refractive index of 1.80 to 2.8, more preferably 1.9 to 2.8. The average particle size of the primary particles is preferably 3 nm to 100 nm, more preferably 5 nm to 100 nm, and particularly preferably 10 nm to 80 nm.
If the refractive index of the high refractive index fine particles is 1.8 or more, the refractive index of the fine particle layer can be effectively increased, and if the refractive index is 2.8 or less, the particles are colored. It is preferable because it is not present. Further, if the average particle diameter of the primary particles of the high refractive index fine particles is 100 nm or less, the haze value of the fine particle layer to be formed is high, and there is no inconvenience such as impairing the transparency of the layer. It is preferable because a high refractive index is maintained.
The particle diameter of the high refractive index fine particles is represented by an average primary particle diameter according to a transmission electron microscope (TEM) photograph. The average primary particle diameter is expressed as an average value of the maximum diameters of the respective fine particles. When the major axis diameter and the minor axis diameter are included, the average value of the major axis diameters of the respective fine particles is defined as the average primary particle diameter.

  Examples of the high refractive index fine particles include oxides such as Ti, Zr, Ta, In, Nd, Sn, Sb, Zn, La, W, Ce, Nb, V, Sm, and Y, complex oxides, and sulfides. The particle | grains which have a main component are mentioned. Here, the main component means a component having the largest content (mass%) among the components constituting the particles. More preferable high refractive index fine particles in the present invention are particles mainly composed of an oxide or composite oxide containing at least one metal element selected from Ti, Zr, Ta, In, and Sn.

The high refractive index fine particles may contain various elements in the particles (hereinafter, such elements may be referred to as containing elements).
Examples of the contained element include Li, Si, Al, B, Ba, Co, Fe, Hg, Ag, Pt, Au, Cr, Bi, P, and S. In the case of tin oxide and indium oxide, it is preferable to contain an element such as Sb, Nb, P, B, In, V, or halogen in order to increase the conductivity of the particles, and in particular, antimony oxide is contained in an amount of 5% by mass to 20%. Most preferred is a composition containing 1% by mass.

The high refractive index fine particles are inorganic fine particles mainly composed of titanium dioxide containing at least one element selected from Co, Zr, and Al as contained elements (hereinafter also referred to as “specific oxide”). Is mentioned. Among these, Co is particularly preferable.
The total content of Co, Al, and Zr is preferably 0.05% by mass to 30% by mass with respect to Ti, more preferably 0.1% by mass to 10% by mass, and 0.2% by mass. % To 7% by mass is more preferable, 0.3% to 5% by mass is particularly preferable, and 0.5% to 3% by mass is most preferable.
The contained elements Co, Al and Zr are present inside or on the surface of the high refractive index fine particles mainly composed of titanium dioxide. It is more preferable that it exists in the high refractive index fine particle mainly composed of titanium dioxide, and it is more preferable that it exists in both the inside and the surface. Among these contained elements, the metal element may exist as an oxide.

As another preferable high refractive index fine particle, composite oxidation of titanium element and at least one metal element (hereinafter also abbreviated as “Met”) selected from metal elements whose oxide has a refractive index of 1.95 or more. In addition, the composite oxide includes inorganic fine particles doped with at least one metal ion selected from Co ions, Zr ions, and Al ions (sometimes referred to as “specific multi-oxide”). Can be mentioned. Here, examples of the metal element whose refractive index of the oxide is 1.95 or more include Ta, Zr, In, Nd, Sb, Sn, Bi, and the like. Among these, Ta, Zr, Sn, and Bi are particularly preferable.
From the viewpoint of maintaining the refractive index, the content of the metal ions doped in the specific composite oxide is within a range not exceeding 25 mass% with respect to the total amount of metal [Ti + Met] constituting the composite oxide. To 0.05 mass% to 10 mass%, more preferably 0.1 mass% to 5 mass%, and particularly preferably 0.3 mass% to 3 mass%.

  The doped metal ion may exist as a metal ion or in any form of a metal atom, and may appropriately exist from the surface to the inside of the composite oxide. It is preferable to exist both on the surface and inside of the composite oxide.

  The high refractive index fine particles preferably have a crystal structure. The crystal structure is preferably composed mainly of rutile, a mixed crystal of rutile / anatase, and anatase, particularly preferably a rutile structure. Accordingly, the high refractive index fine particles of the specific oxide or specific double oxide have a refractive index of 1.9 to 2.8, which is preferable. The refractive index is more preferably 2.1 to 2.8, still more preferably 2.2 to 2.8. As a result, the photocatalytic activity of titanium dioxide can be suppressed, and the weather resistance of the fine particle layer itself and the upper / lower layers in contact with the fine particle layer can be remarkably improved.

  A conventionally well-known method can be used for the method of doping the above-mentioned specific metal element or metal ion. For example, methods described in JP-A-5-330825, 11-263620, JP-A-11-512336, European Patent No. 0335773, etc .; ion implantation method [for example, Shunichi Gonda, Jun Ishikawa 3. Eiji Kamijo, “Ion Beam Application Technology” CMC Co., Ltd., published in 1989, Yasushi Aoki, “Surface Science” 18 (5), 262, 1998, Shoichi Anbo, “Surface Science” 20 (2), p. 60, 1999, etc.].

The high refractive index fine particles may be surface treated. The surface treatment is a modification of the surface of the particles using an inorganic compound and / or an organic compound, whereby the wettability of the surface of the high refractive index fine particles is adjusted, and fine particles in an organic solvent are obtained. Dispersibility and dispersion stability in the refractive index composition are improved. Examples of inorganic compounds adsorbed physicochemically on the particle surface include silicon-containing inorganic compounds (such as SiO ₂ ), aluminum-containing inorganic compounds [Al ₂ O ₃ , Al (OH) _3, etc.], and cobalt. Inorganic compounds containing (CoO ₂ , Co ₂ O ₃ , Co ₃ O ₄ etc.), inorganic compounds containing zirconium [ZrO ₂ , Zr (OH) ₄ etc.], inorganic compounds containing iron (Fe ₂ O ₃ etc.) ), Etc.

  As the organic compound used for the surface treatment, conventionally known surface modifiers of inorganic fillers such as metal oxides and inorganic pigments can be used. For example, it is described in “Pigment Dispersion Stabilization and Surface Treatment Technology / Evaluation”, Chapter 1 (Technical Information Association, published in 2001).

  Specifically, an organic compound having a polar group having an affinity for the surface of the high refractive index fine particles and a coupling compound can be mentioned. Examples of the polar group having an affinity for the surface of the high refractive index fine particles include a carboxy group, a phosphono group, a hydroxy group, a mercapto group, a cyclic acid anhydride group, an amino group, and the like. Compounds containing are preferred. For example, long chain aliphatic carboxylic acids (eg stearic acid, lauric acid, oleic acid, linoleic acid, linolenic acid, etc.), polyol compounds (eg pentaerythritol triacrylate, dipentaerythritol pentaacrylate, ECH (epichlorohydrin) modified glycerol triacrylate Etc.], phosphono group-containing compounds {for example, EO (ethylene oxide) -modified phosphate triacrylate, etc.}, alkanolamines {ethylenediamine EO adducts (5 mol), etc.}.

  As said coupling compound, a conventionally well-known organometallic compound is mentioned, A silane coupling agent, a titanate coupling agent, an aluminate coupling agent etc. are contained. Silane coupling agents are most preferred. Specific examples include compounds described in paragraph numbers [0011] to [0015] of JP-A Nos. 2002-9908 and 2001-310423. Two or more kinds of compounds used for these surface treatments can be used in combination.

  The high refractive index fine particles are also preferably fine particles having a core / shell structure in which a shell made of another inorganic compound is formed using the high refractive index fine particles as a core. The shell is preferably an oxide composed of at least one element selected from Al, Si, and Zr. Specifically, for example, the contents described in JP-A-2001-166104 can be mentioned.

The shape of the high refractive index fine particles is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a rice granular shape, a spherical shape, a cubic shape, a spindle shape or an indefinite shape is preferable. The high refractive index fine particles may be used alone or in combination of two or more.
The content of the high refractive index fine particles is not particularly limited and can be appropriately selected according to the purpose, but is preferably in a range in which the refractive index of the polymer can be 1.55 to 1.95. .

  The matrix is preferably at least one of (A) an organic binder, (B) an organometallic compound containing a hydrolyzable functional group, and a partial condensate of this organometallic compound.

-(A) Organic binder-
As the organic binder (A), (1) a conventionally known thermoplastic resin,
(2) A combination of a conventionally known reactive curable resin and a curing agent, or (3) a combination of a binder precursor (such as a curable polyfunctional monomer or polyfunctional oligomer described below) and a polymerization initiator. Binders to be used.

  It is preferable that a high refractive index composition is prepared from a dispersion containing the organic binder (1), (2) or (3), fine particles and a dispersant. This composition is applied onto a support to form a coating film, and then cured by a method according to the component for forming a binder to form a fine particle layer. The curing method is appropriately selected depending on the type of the binder component. For example, a crosslinking reaction or a polymerization reaction of a curable compound (for example, a polyfunctional monomer or a polyfunctional oligomer) is performed by at least one of heating and light irradiation. The method to make it occur is mentioned. Especially, the method of forming the binder which hardened | cured the crosslinking reaction or the polymerization reaction of the curable compound by irradiating light using the combination of said (3) is preferable.

  Furthermore, it is preferable that the dispersing agent contained in the fine particle dispersion is subjected to a crosslinking reaction or a polymerization reaction simultaneously with or after the application of the high refractive index composition.

  The binder in the cured film produced in this way is, for example, a curable polyfunctional monomer or polyfunctional oligomer, which is a precursor of the dispersant, and the precursor of the binder undergoes a crosslinking or polymerization reaction, and the binder has an anion of the dispersant. It becomes a form in which a sex group is incorporated. Furthermore, since the binder in the cured film has a function of maintaining the dispersion state of the high refractive index fine particles, the crosslinked or polymerized structure imparts a film forming ability to the binder and contains the high refractive index fine particles. The physical strength, chemical resistance, and weather resistance in the cured film can be improved.

{Thermoplastic resin (A-1)}
There is no restriction | limiting in particular as a thermoplastic resin of said (1), According to the objective, it can select suitably, For example, a polystyrene resin, a polyester resin, a cellulose resin, a polyether resin, a vinyl chloride resin, a vinyl acetate resin, Examples thereof include a vinyl chloride-vinyl copolymer resin, a polyacrylic resin, a polymethacrylic resin, a polyolefin resin, a urethane resin, a silicone resin, and an imide resin.

{Combination of reactive curable resin and curing agent (A-2)}
As the reactive curable resin (2), it is preferable to use a thermosetting resin and / or an ionizing radiation curable resin.
There is no restriction | limiting in particular as said thermosetting resin, According to the objective, it can select suitably, For example, a phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy Resins, amino alkyd resins, melamine-urea cocondensation resins, silicon resins, polysiloxane resins and the like can be mentioned.
The ionizing radiation curable resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a radical polymerizable unsaturated group {(meth) acryloyloxy group, vinyloxy group, styryl group, vinyl group, etc. } And / or a resin having a functional group such as a cationic polymerizable group (epoxy group, thioepoxy group, vinyloxy group, oxetanyl group, etc.), for example, a relatively low molecular weight polyester resin, polyether resin, (meth) acrylic resin, Examples thereof include epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, and polythiol polyene resins.

  As necessary for these reactive curable resins, a crosslinking agent (epoxy compound, polyisocyanate compound, polyol compound, polyamine compound, melamine compound, etc.), polymerization initiator (azobis compound, organic peroxide compound, organic halogen compound, Conventionally known compounds such as curing agents such as onium salt compounds and UV photoinitiators such as ketone compounds) and polymerization accelerators (organic metal compounds, acid compounds, basic compounds, etc.) are used. Specific examples include compounds described by Fuzo Yamashita and Tosuke Kaneko “Crosslinking Agent Handbook” (published by Taiseisha, 1981).

{Combination of binder precursor and polymerization initiator (A-3)}
Hereinafter, a method for forming a cured binder by crosslinking or polymerizing a curable compound by light irradiation using the combination of (3), which is a preferable method for forming a cured binder, will be mainly described.

  The functional group of the photocurable polyfunctional monomer or polyfunctional oligomer which is the precursor of the binder may be any of a radical polymerizable functional group and a cationic polymerizable functional group.

  Examples of the radical polymerizable functional group include ethylenically unsaturated groups such as a (meth) acryloyl group, a vinyloxy group, a styryl group, and an allyl group. Among these, a (meth) acryloyl group is preferable, and a polyfunctional monomer containing two or more radical polymerizable groups in the molecule is particularly preferable.

  The radical polymerizable polyfunctional monomer is preferably selected from compounds having at least two terminal ethylenically unsaturated bonds. Among these, compounds having 2 to 6 terminal ethylenically unsaturated bonds in the molecule are particularly preferable. Such a compound group is widely known in the polymer material field, and these can be used without any particular limitation. These can have chemical forms such as monomers, prepolymers (ie, dimers, trimers and oligomers) or mixtures thereof, and copolymers thereof.

  Examples of the radical polymerizable monomer include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters thereof, amides, and the like. Among these, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are particularly preferable.

  Also, addition reaction products of unsaturated carboxylic acid esters and amides having a nucleophilic substituent such as hydroxyl group, amino group and mercapto group with monofunctional or polyfunctional isocyanates and epoxies, polyfunctional carboxylic acids. A dehydration condensation reaction product with an acid or the like is also preferably used. A reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As yet another example, a compound group in which an unsaturated phosphonic acid, styrene, or the like is substituted for the unsaturated carboxylic acid may be used.

  Examples of the aliphatic polyhydric alcohol compound include alkanediol, alkanetriol, cyclohexanediol, cyclohexanetriol, inositol, cyclohexanedimethanol, pentaerythritol, sorbitol, dipentaerythritol, tripentaerythritol, glycerin, diglycerin and the like. Polymerizable ester compounds (monoesters or polyesters) of these aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids, for example, as described in paragraph numbers [0026] to [0027] of JP-A No. 2001-139663 Compounds.

  Examples of other polymerizable esters include, for example, vinyl alcohol, allyl methacrylate, allyl acrylate, aliphatic alcohols described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, and the like. Those having an ester group, those having an aromatic skeleton described in JP-A-2-226149, those having an amino group described in JP-A-1-165613, and the like are also preferably used.

  Specific examples of polymerizable amides formed from aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis (meth) acrylamide, 1,6-hexamethylene bis (meth) acrylamide, and diethylenetriamine tris (meth) acrylamide. And xylylene bis (meth) acrylamide, and those having a cyclohexylene structure described in JP-B No. 54-21726.

  Furthermore, vinylurethane compounds containing two or more polymerizable vinyl groups in one molecule (Japanese Patent Publication No. 48-41708, etc.), urethane acrylates (Japanese Patent Publication No. 2-16765, etc.), ethylene oxide skeleton Described in JP-B-62-39418, polyester acrylates (JP-B 52-30490, etc.), and further, described in Japan Adhesion Association Vol. 20, No. 7, pages 300-308 (1984). Photocurable monomers and oligomers can also be used. Two or more kinds of these radical polymerizable polyfunctional monomers may be used in combination.

  Next, a cationically polymerizable group-containing compound (hereinafter also referred to as “cationic polymerizable compound” or “cationic polymerizable organic compound”) that can be used for forming the binder of the fine particle layer will be described.

  As the cationic polymerizable compound, any compound that undergoes a polymerization reaction and / or a crosslinking reaction when irradiated with an active energy ray in the presence of an active energy ray-sensitive cationic polymerization initiator can be used. Examples thereof include a compound, a cyclic thioether compound, a cyclic ether compound, a spiro orthoester compound, a vinyl hydrocarbon compound, and a vinyl ether compound. One or more of the cationically polymerizable organic compounds may be used.

  As the cation polymerizable group-containing compound, the number of cation polymerizable groups in one molecule is preferably 2 to 10, and more preferably 2 to 5. The average molecular weight of the compound is preferably 3,000 or less, more preferably 200 to 2,000, and still more preferably 400 to 1,500. If the average molecular weight is not less than the lower limit value, there will be no inconvenience such as volatilization in the film forming process, and if it is not more than the upper limit value, the compatibility with the high refractive index composition is poor. This is preferable because it does not cause problems such as.

  Examples of the epoxy compound include aliphatic epoxy compounds and aromatic epoxy compounds.

  Examples of the aliphatic epoxy compounds include polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, polyglycidyl esters of aliphatic long-chain polybasic acids, homopolymers and copolymers of glycidyl acrylate and glycidyl methacrylate, and the like. be able to. In addition to the above epoxy compounds, for example, monoglycidyl ethers of higher aliphatic alcohols, glycidyl esters of higher fatty acids, epoxidized soybean oil, butyl epoxide stearate, octyl epoxide stearate, epoxidized linseed oil, epoxidized polybutadiene, etc. Can be mentioned. Examples of the alicyclic epoxy compound include polyglycidyl ethers of polyhydric alcohols having at least one alicyclic ring, or unsaturated alicyclic rings (for example, cyclohexene, cyclopentene, dicyclooctene, tricyclodecene, etc. ) Cyclohexene oxide or cyclopentene oxide-containing compound obtained by epoxidizing the containing compound with a suitable oxidizing agent such as hydrogen peroxide or peracid.

  Examples of the aromatic epoxy compounds include monovalent or polyvalent phenols having at least one aromatic nucleus, or mono- or polyglycidyl ethers of alkylene oxide adducts thereof. Examples of these epoxy compounds include compounds described in paragraphs [0084] to [0086] in JP-A-11-242101, and paragraphs [0044] to [0046] in JP-A-10-158385. And the compounds described.

  Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable, and alicyclic epoxides are particularly preferable in consideration of fast curability. One of the epoxy compounds may be used alone, or two or more may be used in appropriate combination.

  Examples of the cyclic thioether compound include compounds having a thioepoxy ring instead of the epoxy ring of the epoxy compound.

  Specific examples of the compound containing an oxetanyl group as a cyclic ether include the compounds described in paragraphs [0024] to [0025] in JP-A No. 2000-239309. These compounds are preferably used in combination with an epoxy group-containing compound.

  Examples of the spiro orthoester compound include compounds described in JP 2000-506908 A.

  Examples of vinyl hydrocarbon compounds include styrene compounds, vinyl group-substituted alicyclic hydrocarbon compounds (vinyl cyclohexane, vinyl bicycloheptene, etc.), compounds described in the above radical polymerizable monomers, propenyl compounds {"J. Polymer Science: Part A". : Polymer Chemistry ", Vol. 32, page 2895 (1994), etc.}, alkoxy allene compounds {" J. Polymer Science: Part A: Polymer Chemistry ", Vol. 33, page 2493 (1995), etc.}, vinyl compounds {" J. Polymer Science: Part A: Polymer Chemistry ", 34, 1015 (1996), JP-A-2002-29162, etc.}, isopropenyl compound {" J. Pol " ymer Science: Part A: Polymer Chemistry ", vol. 34, page 2051 (1996), etc.}. You may use these in combination of 2 or more types as appropriate.

  The polyfunctional compound is preferably a compound containing at least one of each selected from the radical polymerizable group and the cationic polymerizable group in the molecule. Examples thereof include compounds described in paragraph numbers [0031] to [0052] in JP-A-8-277320, compounds described in paragraph number [0015] in JP-A 2000-191737, and the like. The compounds used in the present invention are not limited to these.

  The radical polymerizable compound and the cationic polymerizable compound described above are preferably contained in a mass ratio of radical polymerizable compound: cation polymerizable compound in a ratio of 90:10 to 20:80, and 80:20 It is more preferable to contain in the ratio of -30: 70.

  Next, the polymerization initiator used in combination with the binder precursor in the combination (3) will be described in detail.

Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator.
The polymerization initiator is preferably a compound that generates radicals or acids upon irradiation with light and / or heat. The photopolymerization initiator preferably has a maximum absorption wavelength of 400 nm or less. Thus, the handling can be performed under a white light by setting the absorption wavelength to the ultraviolet region. A compound having a maximum absorption wavelength in the near infrared region can also be used.

  The compound that generates radicals refers to a compound that generates radicals by irradiation with light and / or heat, and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. A known polymerization initiator or a compound having a bond with a small bond dissociation energy can be appropriately selected and used. Moreover, the compound which generate | occur | produces a radical can be used individually or in combination of 2 or more types.

  Examples of the compound that generates radicals include conventionally known organic peroxide compounds, thermal radical polymerization initiators such as azo polymerization initiators, organic peroxide compounds (JP-A No. 2001-139663, etc.), amine compounds ( JP-B-44-20189), metallocene compounds (described in JP-A-5-83588, JP-A-1-304453, etc.), hexaarylbiimidazole compounds (US Pat. No. 3,479,185, etc.) And a radical photopolymerization initiator such as an organic halogenated compound, a carbonyl compound, and an organic boric acid compound, etc., and disulfone compounds (JP-A-5-239015, JP-A-61-166544, etc.).

  Specific examples of the organic halogenated compounds include Wakabayashi et al., “Bull. Chem. Soc Japan”, 42, 2924 (1969), US Pat. No. 3,905,815, 27830, M.M. P. Hutt, “J. Heterocyclic Chemistry”, Vol. 1 (No. 3), (1970) ”and the like, and in particular, an oxazole compound substituted with a trihalomethyl group: an s-triazine compound. More preferable examples include s-triazine derivatives in which at least one mono, di, or trihalogen-substituted methyl group is bonded to the s-triazine ring.

  Examples of the carbonyl compound include, for example, “Latest UV Curing Technology”, pages 60 to 62 [published by Technical Information Association, 1991], paragraph numbers [0015] to [0016] of JP-A-8-134404, Examples include the compounds described in paragraphs [0029] to [0031] of Kaihei 11-217518, and benzoin compounds such as acetophenone, hydroxyacetophenone, benzophenone, thioxan, benzoin ethyl ether, and benzoin isobutyl ether; Examples include benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate and ethyl p-diethylaminobenzoate, benzyldimethyl ketal, and acylphosphine oxide.

  Examples of the organic borate compound include, for example, Japanese Patent Nos. 2764769 and 2002-116539, and Kunz, Martin, “Rad. Tech'98. Proceeding April 19-22, 1998, Chicago”. And the organic borates described in the above. Examples thereof include compounds described in paragraph numbers [0022] to [0027] of JP-A-2002-116539. Examples of other organic boron compounds include JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, JP-A-7-306527, and JP-A-7-292014. Specific examples include organoboron transition metal coordination complexes.

  These radical generating compounds may be added alone or in combination of two or more. As addition amount, it is preferable that it is 0.1 mass%-30 mass% with respect to radical polymerization monomer whole quantity, It is more preferable that it is 0.5 mass%-25 mass%, 1 mass%-20 mass% % Is more preferable. In the range of the addition amount, the high-refractive index composition has high polymerizability without problems with time.

Next, a photoacid generator that can be used as a photopolymerization initiator will be described in detail.
Examples of the photoacid generator include known compounds such as photoinitiators for photocationic polymerization, photodecolorants for dyes, photochromic agents, or known photoacid generators used in microresists, and the like. And the like. Examples of the photoacid generator include organic halogenated compounds, disulfone compounds, onium compounds, and the like. Among these, organic halogenated compounds and disulfone compounds are particularly preferable. Specific examples of the organic halogen compound and the disulfone compound are the same as those described for the compound generating the radical.

  Examples of the onium compounds include diazonium salts, ammonium salts, iminium salts, phosphonium salts, iodonium salts, sulfonium salts, arsonium salts, selenonium salts, and the like. For example, paragraph numbers [0058] to JP-A-2002-29162 And the compounds described in [0059].

  As the acid generator, an onium salt is particularly preferably used, and among them, a diazonium salt, an iodonium salt, a sulfonium salt, and an iminium salt are preferable from the viewpoint of photosensitivity at the start of photopolymerization, material stability of the compound, and the like.

  Specific examples of the onium salt include, for example, an amylated sulfonium salt described in paragraph [0035] of JP-A-9-268205, and paragraphs [0010] to [0010] of JP-A 2000-71366. [0011] diaryl iodonium salt or triarylsulfonium salt described in JP-A-2001-288205, sulfonium salt of thiobenzoic acid S-phenyl ester described in JP-A-2001-288205, paragraph of JP-A-2001-133696 Examples include the onium salts described in the numbers [0030] to [0033].

  Other examples of the photoacid generator include organic metal / organic halides described in JP-A-2002-29162, paragraphs [0059] to [0062], and photoacids having an o-nitrobenzyl type protecting group. Examples thereof include compounds such as a generator and a compound that generates photosulfonic acid to generate sulfonic acid (such as iminosulfonate).

  These acid generators may be used alone or in combination of two or more. The addition amount of the acid generator is preferably 0.1% by mass to 20% by mass, more preferably 0.5% by mass to 15% by mass, and more preferably 1% by mass to 10% by mass with respect to the total mass of the total cationic polymerizable monomer. % Is more preferable. The addition amount is preferable in the above range from the stability of the high refractive index composition, the polymerization reactivity, and the like.

  The high refractive index composition is 0.5% by mass to 10% by mass of the radical polymerization initiator or 1% by mass to 10% by mass of the cationic polymerization initiator with respect to the total mass of the radical polymerizable compound or the cationic polymerizable compound. %, Preferably 1% to 5% by weight of radical polymerization initiator, or more preferably 2% to 6% by weight of cationic polymerization initiator.

  When performing the polymerization reaction by ultraviolet irradiation, the high refractive index composition may be used in combination with a conventionally known ultraviolet spectral sensitizer and chemical sensitizer. Examples of these sensitizers include Michler's ketone, amino acids (such as glycine), and organic amines (such as butylamine and dibutylamine).

  Moreover, when performing a polymerization reaction by near infrared irradiation, it is preferable to use a near infrared spectral sensitizer together. The near-infrared spectral sensitizer used in combination may be a light-absorbing substance having an absorption band in at least a part of the wavelength region of 700 nm or more, and a compound having a molecular extinction coefficient of 10,000 or more is preferable. Furthermore, a value having absorption in the region of 750 nm to 1,400 nm and a molecular extinction coefficient of 20,000 or more is preferable. Moreover, it is more preferable that there is a trough of absorption in the visible light wavelength region of 420 nm to 700 nm, and it is optically transparent.

  As the near infrared spectral sensitizer, various pigments and dyes known as near infrared absorbing pigments and near infrared absorbing dyes can be used. Among these, it is preferable to use a conventionally known near-infrared absorber. Commercially available dyes and literature {for example, “Chemical Industry”, May 1986, pages 45-51, “Near-Infrared Absorbing Dye”, “Development and Market Trends of Functional Dyes in the 1990s”, Chapter 2.3. (1990) CMC, “Special Function Dye” [edited by Ikemori and Pilatani, 1986, issued by CMC Co., Ltd.], J. Am. FABIAN, “Chem. Rev.”, Vol. 92, pp. 1197-1226 (1992)}, a catalog published in 1995 by Nippon Sensitive Dye Research Institute, and Exciton Inc. Can be used as well as known dyes described in laser dye catalogs and patents issued in 1989.

(B) An organometallic compound containing a hydrolyzable functional group and a partial condensate of this organometallic compound A coating film by a sol / gel reaction using an organometallic compound containing a hydrolyzable functional group as the matrix It is also preferable to form a cured film after formation.

Examples of the organometallic compound include compounds composed of Si, Ti, Zr, Al, and the like.
Examples of the hydrolyzable functional group include an alkoxy group, an alkoxycarbonyl group, a halogen atom, and a hydroxyl group. Among these, alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group are particularly preferable. A preferred organometallic compound is an organosilicon compound represented by the following general formula (2) and a partial hydrolyzate (partial condensate) thereof. In addition, it is a well-known fact that the organosilicon compound represented by the general formula (2) is easily hydrolyzed and subsequently undergoes a dehydration condensation reaction.

Formula (2): (R ²¹ ) _β- Si (Y ²¹ ) _4-β
However, In the general formula ^{(2), R 21} represents a substituted or unsubstituted C 1-30 aliphatic group or an aryl group having 6 to 14 carbon atoms. Y ²¹ represents a halogen atom (a chlorine atom, a bromine atom, etc.), an OH group, an OR ²² group, or an OCOR ²² group. Here, R ²² represents a substituted or unsubstituted alkyl group. β represents an integer of 0 to 3, preferably 0, 1 or 2, particularly preferably 1. However, when β is 0, Y ²¹ represents an OR ²² group or an OCOR ²² group.

In the general formula (2), the aliphatic group represented by R ²¹ preferably has 1 to 18 carbon atoms (for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, hexadecyl, octadecyl, benzyl). Group, phenethyl group, cyclohexyl group, cyclohexylmethyl, hexenyl group, decenyl group, dodecenyl group, etc.). More preferably, it has 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms. Examples of the aryl group for R ²¹ include phenyl, naphthyl, anthranyl and the like, and a phenyl group is preferable.

  The substituent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, halogen (fluorine, chlorine, bromine, etc.), hydroxyl group, mercapto group, carboxyl group, epoxy group, alkyl group (methyl, Ethyl, i-propyl, propyl, t-butyl, etc.), aryl groups (phenyl, naphthyl, etc.), aromatic heterocyclic groups (furyl, pyrazolyl, pyridyl, etc.), alkoxy groups (methoxy, ethoxy, i-propoxy, hexyloxy) Etc.), aryloxy (phenoxy etc.), alkylthio group (methylthio, ethylthio etc.), arylthio group (phenylthio etc.), alkenyl group (vinyl, 1-propenyl etc.), alkoxysilyl group (trimethoxysilyl, triethoxysilyl etc.) , Acyloxy groups {acetoxy, (meth) acryloyl etc.}, alcohol Sicarbonyl group (methoxycarbonyl, ethoxycarbonyl etc.), aryloxycarbonyl group (phenoxycarbonyl etc.), carbamoyl group (carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl etc.), Acylamino groups (acetylamino, benzoylamino, acrylamino, methacrylamino, etc.) are preferred.

  Of these substituents, more preferred are a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, an alkoxysilyl group, an acyloxy group, and an acylamino group, and particularly preferred are an epoxy group and a polymerizable acyloxy group {( (Meth) acryloyl}, a polymerizable acylamino group (acrylamino, methacrylamino). These substituents may be further substituted.

As described above, R ²² represents a substituted or unsubstituted alkyl group, and the alkyl group is not particularly limited, and examples thereof include the same as the aliphatic group of R ²¹ , and the explanation of the substituent in the alkyl group is R ²¹ .

  The content of the compound of the general formula (2) is preferably 10% by mass to 80% by mass, more preferably 20% by mass to 70% by mass, and more preferably 30% by mass based on the total solid content of the high refractive index composition. It is still more preferable that it is% -50 mass%.

  Examples of the compound of the general formula (2) include compounds described in paragraph numbers [0054] to [0056] of JP-A No. 2001-166104.

  In the high refractive index composition, the organic binder preferably has a silanol group. It is preferable that the binder has a silanol group because the physical strength, chemical resistance, and weather resistance of the fine particle layer are further improved. The silanol group is contained, for example, as a binder forming component constituting a high refractive index composition in a binder precursor (such as a curable polyfunctional monomer or polyfunctional oligomer), a polymerization initiator, or a dispersion of high refractive index fine particles. The organosilicon compound represented by the general formula (2) having a crosslinkable or polymerizable functional group is blended in the high refractive index composition together with the dispersing agent, and the high refractive index composition is coated on the transparent support. Then, the dispersant, the polyfunctional monomer, the polyfunctional oligomer, and the organosilicon compound represented by the general formula (2) can be introduced into the binder by a crosslinking reaction or a polymerization reaction.

  The hydrolysis / condensation reaction for curing the organometallic compound is preferably performed in the presence of a catalyst. Examples of the catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid; organic acids such as oxalic acid, acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, and toluenesulfonic acid; sodium hydroxide, potassium hydroxide, ammonia, and the like. Inorganic bases; organic bases such as triethylamine and pyridine; metal alkoxides such as triisopropoxyaluminum, tetrabutoxyzirconium and tetrabutoxytitanate; metal chelate compounds of β-diketones and β-ketoesters. Specific examples include the compounds described in paragraph numbers [0071] to [0083] in JP-A No. 2000-275403.

  The proportion of these catalyst compounds in the composition is preferably 0.01% by mass to 50% by mass, more preferably 0.1% by mass to 50% by mass, and 0.5% by mass to the organometallic compound. 10 mass% is still more preferable. In addition, it is preferable that reaction conditions are suitably adjusted with the reactivity of an organometallic compound.

  In the high refractive index composition, the matrix preferably has a specific polar group. Examples of the specific polar group include an anionic group, an amino group, and a quaternary ammonium group. Specific examples of the anionic group, amino group, and quaternary ammonium group include the same as those described for the dispersant.

-Solvent-
The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include alcohols, ketones, esters, amides, ethers, ether esters, hydrocarbons, and halogenated hydrocarbons. Etc. Specifically, alcohol (for example, methanol, ethanol, propanol, butanol, benzyl alcohol, ethylene glycol, propylene glycol, ethylene glycol monoacetate, etc.), ketone (for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, etc.), ester ( For example, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl formate, propyl formate, butyl formate, ethyl lactate, etc.), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methyl chloroform), aromatic Group hydrocarbons (eg, benzene, toluene, xylene, etc.), amides (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone, etc.), ethers (eg, dioxane) Emissions, tetrahydrofuran, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, etc.), ether alcohols (such as 1-methoxy-2-propanol, ethyl cellosolve, methyl carbinol and the like). These may be used individually by 1 type and may use 2 or more types together. Among these, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and butanol are particularly preferable. A coating solvent system mainly comprising a ketone solvent (for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.) is also preferably used.
The content of the ketone solvent is preferably 10% by mass or more, more preferably 30% by mass or more, and still more preferably 60% by mass or more of the total solvent contained in the high refractive index composition.

  A matrix having a specific polar group is prepared by, for example, blending a dispersion containing high refractive index fine particles and a dispersant with a high refractive index composition, and a binder precursor having a specific polar group as a cured film forming component (specific A curable polyfunctional monomer or polyfunctional oligomer having a polar group) and a polymerization initiator, and a general polar formula having a specific polar group and a crosslinked or polymerizable functional group (2). At least one of the organic silicon compounds, a monopolar monomer having a specific polar group and a crosslinkable or polymerizable functional group, if desired, and coating the coating composition on the transparent support. Then, the above-mentioned dispersant, monofunctional monomer, polyfunctional monomer, polyfunctional oligomer and / or the organosilicon compound represented by the general formula (2) are obtained by crosslinking or polymerization reaction.

  The monofunctional monomer having the specific polar group is preferable because it can function as a dispersion aid for the high refractive index fine particles in the high refractive index composition. Furthermore, after coating, a uniform dispersion of high refractive index fine particles in the fine particle layer is maintained by crosslinking reaction or polymerization reaction with a dispersant, a polyfunctional monomer or polyfunctional oligomer, or a polymerization reaction to maintain a good physical dispersibility. A fine particle layer having excellent strength, chemical resistance and weather resistance can be produced.

  The coating liquid in which the fine particles are added to the high refractive index composition, on the transparent substrate, for example, dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method, It can be prepared by applying by a known thin film forming method such as a micro gravure coating method or an extrusion coating method, followed by drying, light and / or heat irradiation. Preferably, curing by light irradiation is advantageous from rapid curing. Furthermore, it is also preferable to heat-process in the second half of photocuring process.

  The light source for light irradiation may be any one in the ultraviolet light region or near infrared light. Ultraviolet, high pressure, medium pressure, and low pressure mercury lamps, chemical lamps, carbon arc lamps, metal halide lamps may be used as ultraviolet light sources. Xenon lamps, sunlight, etc. Various available laser light sources having a wavelength of 350 nm to 420 nm may be irradiated as a multi-beam. Further, examples of the near-infrared light source include a halogen lamp, a xenon lamp, and a high-pressure sodium lamp. Various available laser light sources having a wavelength of 750 nm to 1,400 nm may be irradiated in a multi-beam form.

In the case of radical photopolymerization by light irradiation, it can be carried out in air or in an inert gas, but in order to shorten the polymerization induction period of the radically polymerizable monomer or sufficiently increase the polymerization rate, etc. It is preferable that the atmosphere has a reduced oxygen concentration. Irradiation intensity of ultraviolet irradiation is ^preferably from 0.1mW / cm ² ~100mW / cm 2 or so, an amount of light irradiation on the coating film surface is 100mJ ^/ cm ² ~1,000mJ ^/ cm 2 is preferred. Further, the temperature distribution of the coating film in the light irradiation step is preferably as uniform as possible, preferably within ± 3 ° C., and more preferably controlled within ± 1.5 ° C. In this range, the polymerization reaction in the in-plane and in-layer depth directions of the coating film proceeds uniformly, which is preferable.

The average thickness of the fine particle layer is preferably 5 μm to 200 μm, and more preferably 5 μm to 50 μm. When the average thickness is less than 5 μm, there is no sufficient light angle conversion by the fine particle layer, and as shown in FIG. 14, the maximum light extraction efficiency may not be obtained, and when it exceeds 200 μm, the light is scattered. As a result, the amount of backscattered light increases, the amount of light returning to the inside of the organic electroluminescent element increases, the light extraction efficiency decreases, and the thick fine particle layer may lead to high costs.
The average thickness can be determined, for example, by cutting a part of the fine particle layer and measuring with a scanning electron microscope (S-3400N, manufactured by Hitachi High-Tech Co., Ltd.).

<Organic electroluminescent layer>
The organic electroluminescent layer has at least a light emitting layer, and may have a transparent electrode, if necessary, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, and the like. May each have other functions. Various materials can be used for forming each layer.

-Light emitting layer-
The material of the light emitting layer is not particularly limited and may be appropriately selected depending on the purpose. Holes can be injected from the anode, the hole injection layer, or the hole transport layer when an electric field is applied, and the cathode Alternatively, a layer having the function of injecting electrons from the electron injection layer, the electron transport layer, the function of moving the injected charge, and the function of emitting light by providing a field for recombination of holes and electrons is formed. What can be used can be used.

The material of the light emitting layer is not particularly limited and may be appropriately selected depending on the purpose. For example, benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetra Phenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, perylene derivatives, perinone derivatives, oxadiazole derivatives, aldazine derivatives, pyrazine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, Various metal complexes typified by metal complexes and rare earth complexes of cyclopentadiene derivatives, styrylamine derivatives, aromatic dimethylidin compounds, 8-quinolinol derivatives Polythiophene, polyphenylene, polyphenylene vinylene polymer compounds, and the like. These may be used individually by 1 type and may use 2 or more types together.
There is no restriction | limiting in particular in the thickness of the said light emitting layer, According to the objective, it can select suitably, 1 nm-5 micrometers are preferable, 5 nm-1 micrometer are more preferable, 10 nm-500 nm are still more preferable.
The method for forming the light emitting layer is not particularly limited and may be appropriately selected depending on the purpose. For example, resistance heating vapor deposition, electron beam, sputtering, molecular lamination method, coating method (spin coating method, casting method, dip coating) Method) and LB method. Among these, resistance heating vapor deposition and a coating method are particularly preferable.

-Transparent electrode-
The material for the transparent electrode is not particularly limited and may be appropriately selected depending on the intended purpose. For example, tin-doped indium oxide (ITO) (refractive index (n) = 2.0), zinc-doped indium oxide (IZO) ), ZnO (refractive index (n) = 1.95), SnO ₂ (refractive index (n) = 2.0), In ₂ O ₃ (refractive index (n) = 1.9 to 2.0), TiO ₂ (refractive index (n) = 1.90). Among these, ITO and IZO are particularly preferable.
The refractive index of the transparent electrode is preferably 1.65 to 2.2.
The average thickness of the transparent electrode is preferably 20 nm to 200 nm, and more preferably 40 nm to 100 nm.

-Hole injection layer, hole transport layer-
The material of the hole injection layer or the hole transport layer has any one of a function of injecting holes from the anode, a function of transporting holes, and a function of blocking electrons injected from the cathode. As long as it is a thing, there will be no restriction | limiting in particular, According to the objective, it can select suitably.
Examples of the material of the hole injection layer or the hole transport layer include carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, aryls. Amine derivatives, amino-substituted chalcone derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, Examples thereof include poly (N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers, and conductive polymer oligomers such as polythiophene. These may be used individually by 1 type and may use 2 or more types together.

The hole injection layer or the hole transport layer may have a single layer structure composed of one or more of the materials described above, or a multilayer structure composed of a plurality of layers having the same composition or different compositions. Also good.
As a method for forming the hole injection layer or the hole transport layer, for example, a vacuum deposition method, an LB method, a method in which the hole injection / transport agent is dissolved or dispersed in a solvent (a spin coating method, a cast method, A dip coating method or the like is used. In the case of the coating method, it can be dissolved or dispersed together with the resin component.
The resin component is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyvinyl chloride resin, polycarbonate resin, polystyrene resin, polymethyl methacrylate resin, polybutyl methacrylate resin, polyester resin, polysulfone resin , Polyphenylene oxide resin, polybutadiene, poly (N-vinylcarbazole) resin, hydrocarbon resin, ketone resin, phenoxy resin, polyamide resin, ethyl cellulose, vinyl acetate resin, ABS resin, polyurethane resin, melamine resin, unsaturated polyester resin, alkyd Resin, epoxy resin, silicone resin, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
The thickness of the hole injection layer or the hole transport layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 1 nm to 5 μm is preferable, 5 nm to 1 μm is more preferable, and 10 nm to 500 nm is even more. preferable.

-Electron injection layer, electron transport layer-
The material for the electron injection layer or the electron transport layer has any one of a function of injecting electrons from the cathode, a function of transporting electrons, and a function of blocking holes injected from the anode. If there is no restriction | limiting in particular, it can select suitably according to the objective.
Examples of the material for the electron injection layer or the electron transport layer include triazole derivatives, oxazole derivatives, oxadiazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivatives. , Metal complexes of fluorenylidenemethane derivatives, distyrylpyrazine derivatives, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanine derivatives, 8-quinolinol derivatives, metal phthalocyanines, benzoxazoles and benzothiazoles Examples include various metal complexes represented by complexes. These may be used individually by 1 type and may use 2 or more types together.

The electron injection layer or the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .
As a method for forming the electron injection layer or the electron transport layer, for example, a vacuum deposition method, an LB method, a method in which the electron injection / transport agent is dissolved or dispersed in a solvent (a spin coating method, a casting method, a dip coating method). Etc.) are used. In the case of the coating method, it can be dissolved or dispersed together with the resin component, and as the resin component, for example, those exemplified in the case of the hole injection transport layer can be applied.
There is no restriction | limiting in particular in the thickness of the said electron injection layer or an electron carrying layer, According to the objective, it can select suitably, 1 nm-5 micrometers are preferable, 5 nm-1 micrometer are more preferable, and 10 nm-500 nm are still more preferable.

-Other components-
Examples of the other members include a barrier layer, a protective layer, a sealing layer, and a TFT substrate.
The barrier layer is not particularly limited as long as it has a function of preventing permeation of oxygen, moisture, nitrogen oxides, sulfur oxides, ozone and the like in the atmosphere, and can be appropriately selected according to the purpose.
There is no restriction | limiting in particular as a material of the said barrier layer, According to the objective, it can select suitably, For example, SiN, SiON, etc. are mentioned.
There is no restriction | limiting in particular as thickness of the said barrier layer, Although it can select suitably according to the objective, 5 nm-1,000 nm are preferable, 7 nm-750 nm are more preferable, 10 nm-500 nm are still more preferable.
When the thickness of the barrier layer is less than 5 nm, the barrier function for preventing the transmission of oxygen and moisture in the atmosphere may be insufficient. When the thickness exceeds 1,000 nm, the light transmittance decreases and the transparency becomes low. It may be damaged.
The optical properties of the barrier layer are preferably such that the light transmittance is 80% or more, more preferably 85% or more, and still more preferably 90% or more.
There is no restriction | limiting in particular as a formation method of the said barrier layer, According to the objective, it can select suitably, For example, CVD method etc. are mentioned.

The organic electroluminescent device of the present invention may be configured as a device capable of displaying in full color.
As a method for making the organic electroluminescence device of the present invention of a full color type, for example, as described in “Monthly Display”, September 2000, pages 33 to 37, the three primary colors (blue (B ), Green (G), red (R)), each of which emits light corresponding to a three-color light emitting method in which a layer structure for emitting light corresponding to each of the light emitting layers is arranged on a substrate. A white method, a color conversion method for converting blue light emission by a blue light emission layer structure into red (R) and green (G) through a fluorescent dye layer, and the like are known.

  In addition, a planar light source having a desired emission color can be obtained by using a combination of a plurality of layer structures having different emission colors obtained by the above method. For example, a white light-emitting light source that combines blue and yellow light-emitting elements, a white light-emitting light source that combines blue, green, and red light-emitting elements.

  The organic electroluminescent device of the present invention is, for example, various lighting, computer, in-vehicle display, outdoor display, household equipment, commercial equipment, home appliances, traffic display, clock display, calendar display, It can be suitably used in various fields including luminescent screens, audio equipment and the like.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

  Using the following model, simulation was performed as follows using commercially available ray tracing software (product ZEMAX-EE manufactured by ZEMAX Development Corporation).

<Simulation model>
An organic electroluminescent device having a composite reflective layer 6, an organic electroluminescent layer (including a transparent electrode) 2, a transparent substrate 4, and a fine particle layer 5 shown in FIG. 1 in this order was prepared as a simulation model.
The composite reflection layer is a layer obtained by converting the composite reflectivity from the physical properties of the reflective electrode of the organic electroluminescent device and the physical properties of the organic electroluminescent layer, expressed as the type and thickness of the reflective electrode, and expressing it as the reflectivity of the reflective electrode. It is. The reflectance of this composite reflective layer is the reflectance for light returning into the organic electroluminescent layer due to the difference in interlayer refractive index.
Here, Ag, MgAg, or Al was prepared as the reflective electrode.
The combined reflectivity of the organic electroluminescent device is 0.87 for the Ag reflective electrode and 0.83 for the MgAg reflective electrode in consideration of the absorption of the organic electroluminescent layer (including the transparent electrode) and the reflective electrode. In the case of Al reflective electrode: 0.77.
Hereinafter, the composite reflective layer is simply referred to as a reflective electrode. For example, the composite reflective layer is represented by Ag, and when the composite reflectivity is 0.87, it is simply represented by the reflective electrode Ag.
In this organic electroluminescent device, the refractive index ns of the transparent substrate 3 and the refractive index nb of the polymer of the fine particle layer 4 are the same.
The fine particle layer 4 is composed of a polymer and fine particles, and polystyrene (refractive index np = 1.59, attenuation coefficient k = 0) is used as the fine particles.
The light distribution from the organic electroluminescent layer (including the transparent electrode) 2 (refractive index n = 1.8, attenuation coefficient k = 0) was set to be a Lambertian distribution.

<Estimation of composite reflectivity of organic electroluminescent device>
The composite reflectance of the organic electroluminescence device was estimated by the following method.
When the round-trip transmittance in the organic electroluminescent layer is 0.9, the reflectance of the reflective electrode and the organic electroluminescent layer (refractive index n = 1.8) is set to a typical Ag (refractive index n = 0.058, Attenuation coefficient k = 3.58), Mg (refractive index n = 0.32, attenuation coefficient k = 5.33), Al (refractive index n = 0.93, attenuation coefficient k = 6.33) refractive index, And the damping coefficient was used. The reflectance was calculated using the Fresnel equation. As a result, the reflectance of Ag was 0.97, the reflectance of Mg was 0.92, and the reflectance of Al was 0.86.

The composite reflectivity of the organic electroluminescent device was estimated as follows.
In the case of Ag: 0.97 × 0.9 = 0.87
In the case of Mg: 0.92 × 0.9 = 0.828
In the case of Al: 0.86 × 0.9 = 0.77
As the MgAg electrode, an Mg: Ag = 10: 1 (volume ratio) electrode (MgAg electrode) was used as an alloy of Mg and Ag. In this MgAg electrode, when the volume average of Mg and Ag correspond to the average of reflectance, the composite reflectance was assumed to be 0.83 in the case of the MgAg electrode.

<Light distribution of light emitted from organic electroluminescence device to transparent substrate>
As the organic electroluminescent element, one having the following structure disclosed in Vol 459/14 May 2009 / doi: 10.1038 / nature08003 was used.
Glass (OHARA S-LAH53, refractive index n = 1.8) / ITO (thickness 90 nm) / MeO-TPD: NDP-2 (thickness 45 nm) / NPB (thickness 10 nm) / TCTA: Ir (MDQ) ₂ (acac) (Thickness 6 nm) / TCTA (Thickness 2 nm) / TPBi: FIrpic (4 nm) / TPBi (Thickness 2 nm) / TPBi: Ir (ppy) ₃ / TPBi (10 nm) / Bphen: Cs (Thickness 25 nm) / Ag (Thickness 100 nm)
As described in paragraph [0002] of Japanese Patent Application Laid-Open No. 2008-70198, the light distribution of the light emitted from the light emitting layer and emitted into the transparent substrate is assumed to be a Lambertian distribution.

<Light extraction efficiency>
Light extraction efficiency = (light energy emitted up to the air) / (light energy emitted from the effective light emission region)

<Integration efficiency magnification>
Magnification = (light extraction efficiency when there is a fine particle layer) / (light extraction efficiency when there is no fine particle layer)

Example 1
<Simulation 1>
-Effect of change in effective light-emitting area size with respect to element thickness on light extraction efficiency for each reflective electrode-
<< Simulation model >>
As shown in FIG. 1, the specific configuration of the simulation model is as follows.
Air / fine particle layer (polystyrene fine particles: average particle diameter φ = 2 μm, refractive index np = 1.59, attenuation coefficient k = 0, volume filling factor η = 50%; polymer: refractive index nb = 1.8, attenuation coefficient k = 0, thickness L = 15 μm) / transparent substrate (refractive index ns = 1.8, attenuation coefficient k = 0, thickness 1 mm) / organic electroluminescent layer (refractive index n = 1.8, attenuation coefficient k = 0, thickness) 0.2 μm) / composite reflective layer (Ag: reflectance 0.87, MgAg: reflectance 0.83, Al: reflectance 0.77, thickness 100 nm)
As shown in FIG. 1, the effective light emitting area is a 5 mm square, and the size of the non-light emitting area protruding from the outer peripheral edge of the effective light emitting area of the organic electroluminescent layer is changed to change from the outer peripheral edge of the effective light emitting area. The minimum width of the non-light-emitting region that protrudes is set to w, the total average thickness of the organic electroluminescent layer and the transparent substrate is set to d, and the relationship between the ratio (w / d) and the light extraction efficiency is measured with commercially available ray tracing software (ZEMA Simulation was performed using a product of Development Corporation, ZEMAX-EE).

<< Simulation results >>
FIG. 2 is a graph showing the relationship between the ratio (w / d) and the light extraction efficiency for an Ag reflective electrode, an MgAg reflective electrode, and an Al reflective electrode.
From the results shown in FIG. 2, it was found that the light extraction efficiency was higher when the ratio (w / d) was large and the Ag reflection electrode was compared with the MgAg reflection electrode and the Al reflection electrode.
FIG. 3 is an enlarged view of part A in FIG. From the result of FIG. 3, when the ratio (w / d) is 0, there is almost no difference due to the reflective electrode. On the other hand, it was found that the light extraction efficiency of the Ag reflective electrode is the highest in the portion B of FIG. 2 where the ratio (w / d) is large.

Next, the light extraction efficiency shown in FIG. 2 is normalized as follows.
(1) In order to express the influence of the effective light emission size (ratio (w / d)), the light extraction efficiency at w = 0 is subtracted from the light extraction efficiency for each reflective electrode (w = 0). When light extraction efficiency = 0).
(2) The light extraction efficiency when the ratio (w / d) = 100 when the increase in light extraction efficiency has converged was normalized to 1. The standardized result is shown in FIG.
From the results of FIG. 4, it is understood that the Ag reflecting electrode requires a large ratio (w / d) in order to obtain the same increase in light extraction efficiency as compared with the MgAg reflecting electrode and the Al reflecting electrode. It was. For example, it was found that the ratio (w / d) of the Ag reflective electrode is preferably 9 or more in order to obtain the light extraction efficiency of 0.8 times the maximum rate of increase.

(Example 2)
<Simulation 2>
-Results of optimization of the refractive index of the polymer in the fine particle layer, the average particle size of the fine particles, and the volume filling rate of the fine particles by reflective electrode-
<< Simulation model >>
From the result of FIG. 2 of simulation 1, the point where the increase in the light extraction efficiency of the Ag reflection electrode Ag, MgAg reflection electrode, and Al reflection electrode converged is selected, the effective light emitting area is 5 mm square, the entire element is 40 mm square, and transparent. The effect of changing the refractive index ns of the substrate and the parameters of the fine particle layer on the light extraction efficiency was simulated using commercially available ray tracing software (a product of ZEMAX Development Corporation, ZEMAX-EE).

(1) Model without fine particle layer (see Fig. 5)
Air / transparent substrate (BK7) (refractive index n = 1.5, attenuation coefficient k = 0, thickness d = 1 mm) / light emitting layer (refractive index n = 1.8, attenuation coefficient k = 0, thickness 2 μm) / composite Reflective layer (reflective electrode Al, reflectance 0.86 × 0.9 = 0.77, thickness 100 nm)

(2) Model with a fine particle layer (see Fig. 6)
Air / fine particle layer (polymer: refractive index nb, attenuation coefficient k = 0, fine particle layer thickness L; fine particle: refractive index n = 1.59, attenuation coefficient k = 0, particle diameter φ, volume filling factor η) / transparent Substrate (refractive index ns, attenuation coefficient k = 0, thickness 1 mm) / light emitting layer (refractive index n = 1.8, attenuation coefficient k = 0, thickness 2 μm) / composite reflective layer (when reflectivity is Al: 0. 86 × 0.9 = 0.77 Ag: 0.97 × 0.9 = 0.87 Mg: 0.92 × 0.9 = 0.828 Mg and As an alloy of Ag, an electrode (MgAg electrode) having a volume filling ratio of Mg: Ag = 10: 1 (volume ratio) was assumed, and the MgAg electrode corresponds to the volume average particle diameter of Mg and Ag and the average reflectance. 0.83): thickness 100 nm
As the fine particles, polystyrene spherical particles (refractive index n = 1.59, attenuation coefficient k = 0) were used. As the polymer for the fine particle layer, a polymer obtained by dispersing high refractive index nanoparticles (TiO ₂ , refractive index n = 2.6, average particle size of 100 nm or less) in urethane (refractive index n = 1.5) was used.

  Assuming that the light distribution of the light emitted from the effective light emitting region of the organic electroluminescent layer is Lambertian distribution, the refractive index nb of the polymer of the fine particle layer, the thickness L of the fine particle layer, the average particle diameter φ of the fine particles, Commercially available light beam for volume filling factor η, refractive index ns of transparent substrate (assuming ns = nb), Ag reflection electrode, MgAg reflection electrode (Mg: Ag = 10: 1 (volume ratio)), and Al reflection electrode A simulation was performed using tracking software (a product of ZEMAX Development Corporation, ZEMAX-EE), and changes in magnification of light extraction efficiency and integration efficiency were estimated as follows.

<< Simulation results >>
(1) The influence of the refractive index (nb and ns) of the polymer of the fine particle layer and the substrate for each reflective electrode FIG. 7 shows the Ag reflective electrode, the average particle diameter of the polymer of the fine particle layer is 2 μm, and the volume filling rate of fine particles is 50%. A graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are changed to 1.5, 1.8, and 2.0. is there.
FIG. 8 shows the MgAg reflective electrode, the average particle diameter of the polymer of the fine particle layer is 2 μm, the fine particle volume filling ratio is 50%, the refractive index nb of the fine particle layer polymer and the refractive index ns of the transparent substrate are 1.5, 1.8. 4 is a graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when changed to 2.0.
FIG. 9 shows an Al reflective electrode, the average particle diameter of the polymer of the fine particle layer is 2 μm, the fine particle volume filling rate is 50%, and the refractive index nb of the fine particle layer polymer and the refractive index ns of the transparent substrate are 1.5, 1.8. 4 is a graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when changed to 2.0.
From the results of FIGS. 7 to 9, it can be seen that the maximum light extraction efficiency can be obtained when the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are equal to the refractive index of the light emitting layer.
When the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are 1.8, the light extraction efficiency becomes maximum, and ns and nb = 2.0 (2.0 / 1 of the refractive index of the organic electroluminescent layer) .8 times), it was found that the light extraction efficiency was lowered.
It was also found that the maximum light extraction efficiency can be obtained when the fine particle layer is thinner as the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are larger.

FIG. 10 shows that the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are 1.8, the average particle diameter of the fine particle layer is 2 μm, and the volume filling factor of the fine particles is 50%. 5 is a graph showing the relationship between the thickness of the fine particle layer and the magnification of the integral efficiency when changed to an Al reflective electrode.
From the results of FIG. 10, it was found that the Ag reflecting electrode can obtain a larger light extraction efficiency with the same fine particle layer than the AgMg reflecting electrode and the Al reflecting electrode.
In order to obtain the same light extraction efficiency, with the same fine particle and fine particle polymer, the Ag reflective electrode can be realized with a fine particle layer having a thinner thickness than the Ag Mg reflective electrode and the Al reflective electrode. That is, the cost of the fine particle layer and the yield of the fine particle layer can be achieved.

<< Effect of Average Particle Size of Fine Particles in Fine Particle Layer and Volume Filling Ratio of Fine Particles >>
FIG. 11 shows that when the average particle diameter of the fine particles in the fine particle layer is 2 μm, the Ag reflective electrode, the refractive index nb of the polymer in the fine particle layer, and the refractive index ns of the transparent substrate are 1.8, the volume filling rate of the fine particles is 10%. , 20%, 30%, 50%, and 70% are graphs showing the relationship between the fine particle layer thickness and the integral efficiency magnification.
FIG. 12 shows that when the average particle diameter of the fine particles in the fine particle layer is 6 μm, the Ag reflective electrode, the refractive index nb of the polymer in the fine particle layer, and the refractive index ns of the transparent substrate are 1.8, the volume filling rate of the fine particles is 10%. , 20%, 30%, 50%, and 70% are graphs showing the relationship between the fine particle layer thickness and the integral efficiency magnification.
FIG. 13 shows that the average particle diameter of the fine particles is 0.1 when the volume filling rate of the fine particles in the fine particle layer is 20%, the Ag reflecting electrode, the refractive index nb of the polymer of the fine particle layer, and the refractive index ns of the transparent substrate are 1.8. It is the graph which showed the relationship between the thickness of a fine particle layer when changing to 5 micrometers, 1 micrometer, 2 micrometers, 6 micrometers, and 10 micrometers, and the magnification of integral efficiency.
FIG. 14 shows that when the volume filling rate of the fine particles in the fine particle layer is 50%, the Ag reflective electrode, the refractive index nb of the polymer in the fine particle layer, and the refractive index ns of the transparent substrate are 1.8, the average particle size of the fine particles is 0.1. It is the graph which showed the relationship between the thickness of a fine particle layer when changing to 5 micrometers, 1 micrometer, 2 micrometers, 6 micrometers, and 10 micrometers, and the magnification of integral efficiency.
FIG. 15 shows that when the volume filling rate of the fine particles in the fine particle layer is 70%, the Ag reflective electrode, the refractive index nb of the polymer in the fine particle layer, and the refractive index ns of the transparent substrate are 1.8, the average particle size of the fine particles is 0. It is the graph which showed the relationship between the thickness of a fine particle layer when changing to 0.5 micrometer, 1 micrometer, 2 micrometer, 6 micrometers, and 10 micrometers, and the magnification of integral efficiency.
FIG. 16 is an enlarged view of FIG. When the volume filling rate of fine particles in the fine particle layer is 50%, the Ag reflective electrode, the refractive index nb of the polymer of the fine particle layer and the refractive index ns of the transparent substrate are 1.8, the average particle size of the fine particles is 0.5 μm, 1 μm. It is the graph which showed the relationship between the thickness of a fine particle layer when changing to 2 micrometers, 6 micrometers, and 10 micrometers, and the magnification of integral efficiency.

From the results of FIG. 11 to FIG. 16, the thickness of the fine particle layer is adjusted in accordance with the average particle diameter of the fine particles in the fine particle layer and the volume filling rate of the fine particles, and the optimized light extraction efficiency is determined as the optimized light extraction efficiency. To do.
The magnitude of the optimized light extraction efficiency is determined by the values of the reflective electrode material, the refractive index of the transparent substrate, and the refractive index of the polymer of the fine particle layer. The smaller the average particle size of the fine particles, the thinner the optimum fine particle layer thickness. It was found that the smaller the volume filling rate of the fine particles, the thicker the optimum fine particle layer is.
In general, the high refractive index polymer in the fine particles is an expensive material, so that the controllable thickness is preferably as thin as possible. When the average particle diameter of the fine particles is 10 μm or more, the light hitting the fine particles is strongly forward scattered, the light angle conversion ability by the fine particles is reduced, and the light extraction efficiency is lowered. On the other hand, if the average particle size of the fine particles is less than 0.5 μm, Mie scattering is changed to the Rayleigh scattering region, and the chromaticity of the element is greatly changed, and the light extraction efficiency is expected to be lowered. The Therefore, it was found that the average particle diameter of the fine particles is preferably 0.5 μm to 10 μm.
When the thickness of the fine particle layer is 50 μm or less, the volume filling rate of the fine particles is suppressed, which is advantageous for cost reduction. It was found that the average particle diameter of the fine particles that can obtain the maximum integral efficiency magnification when the thickness of the fine particle layer is 50 μm or less is 0.5 μm to 6 μm.
In addition, even if the volume filling rate of the fine particles is 10% to 70%, the same integral efficiency magnification can be obtained if the thickness of the fine particle layer is optimally selected. The range of the volume filling rate of the fine particles that can obtain the maximum integral efficiency magnification when the thickness of the fine particle layer is 50 μm or less is 20% to 70%. Therefore, it was found that the average particle diameter of the fine particles is 0.5 μm to 6 μm, the volume filling rate of the fine particles is 20% to 70%, and the thickness of the fine particle layer is 50 μm or less.

  By the above examination, the organic electroluminescent layer 2 (including the transparent electrode 3) is formed on the light extraction side surface of the high refractive index transparent substrate 4 shown in FIG. 17, and the fine particle layer is formed on the other surface of the high refractive index transparent substrate 4. 5 can be realized.

  The organic electroluminescent device of the present invention is excellent in external extraction efficiency of emitted light, and can achieve low power consumption and long life, for example, various lighting, computer, in-vehicle display, outdoor display, household equipment, It can be suitably used in various fields including business equipment, home appliances, traffic-related indicators, clock indicators, calendar indicators, luminescent screens, audio equipment, and the like.

DESCRIPTION OF SYMBOLS 1 Reflective electrode 2 Organic electroluminescent layer 4 Transparent substrate 5 Fine particle layer 6 Composite reflective layer 7 Effective light emission area 8 Sealing can 10 Organic electroluminescent apparatus

Claims (13)

An organic electroluminescent device having at least a reflective electrode, an organic electroluminescent layer, a transparent substrate, and a light extraction layer in this order,
The organic electroluminescent layer includes at least a transparent electrode and a light emitting layer,
The organic electroluminescent layer has an effective light emitting region and a non-light emitting region,
A total average thickness d of layers and members existing between the reflective electrode and the light extraction layer, and a minimum width w in the non-light emitting region protruding from the outer peripheral edge of the effective light emitting region of the organic electroluminescent layer An organic electroluminescence device having a ratio (w / d) of 40 or more.   The organic electroluminescent device according to claim 1, wherein the total average thickness d of the layers and members existing between the reflective electrode and the light extraction layer is the total average thickness of the organic electroluminescent layer and the transparent substrate.   The organic electroluminescent device according to claim 1, wherein light emitted from the organic electroluminescent layer is emitted from the light extraction layer.   The organic electroluminescent device according to claim 1, wherein the reflective electrode is made of Ag.   The organic electroluminescent device according to any one of claims 1 to 4, wherein the refractive index of the transparent substrate is not less than the refractive index of the organic electroluminescent layer.   The organic electroluminescent device according to claim 5, wherein the refractive index of the transparent substrate is the same as the refractive index of the organic electroluminescent layer.   The organic electroluminescent device according to any one of claims 1 to 6, wherein the light extraction layer is a fine particle layer containing a polymer and fine particles.   The organic electroluminescent device according to claim 7, wherein the refractive index of the polymer in the fine particle layer is different from the refractive index of the fine particles.   The organic electroluminescent device according to any one of claims 7 to 8, wherein the refractive index of the polymer in the fine particle layer is the same as the refractive index of the transparent substrate.   The organic electroluminescence device according to any one of claims 7 to 9, wherein the fine particles have an average particle size of 0.5 µm to 10 µm.   The organic electroluminescent device according to any one of claims 7 to 10, wherein a volume filling rate of the fine particles in the fine particle layer is 20% to 70%.   The organic electroluminescence device according to any one of claims 7 to 11, wherein the average thickness of the fine particle layer is 5 µm to 200 µm. The average particle diameter of the fine particles is 0.5 μm to 6 μm, the volume filling rate of the fine particles in the fine particle layer is 20% to 70%, and the average thickness of the fine particle layer is 50 μm or less. The organic electroluminescent device according to 1.