JP5566069B2 - Organic electroluminescence display - Google Patents

Description

  The present invention relates to an organic electroluminescent display device having high light extraction efficiency and excellent optical characteristics.

  An organic EL device (organic electroluminescent device) is a self-luminous display device, and is used for displays and illumination. The organic EL display has advantages in display performance such as higher visibility than conventional CRTs and LCDs and no viewing angle dependency. There is also an advantage that the display can be reduced in weight and thickness. In addition to the advantages of light weight and thin layers, organic EL lighting has the possibility of realizing illumination in a shape that could not be realized so far by using a flexible substrate.

As described above, the organic EL device has excellent characteristics, but generally, the refractive index of each layer constituting the display device including the light emitting layer is higher than that of air. For example, in an organic EL device, the refractive index of an organic thin film layer such as a light emitting layer is 1.6 to 2.1. For this reason, the emitted light is easily totally reflected at the interface, and the light extraction efficiency may be less than 20%, and most of the light is lost.
For example, an organic EL display unit in a generally known organic EL device includes an organic compound layer disposed between a pair of electrode layers on a substrate. The organic compound layer includes a light emitting layer, and the organic EL device emits light emitted from the light emitting layer from the light extraction surface side. In this case, there is a problem that the light extraction efficiency is low because the total reflection component that is light having a critical angle or more cannot be extracted at the light extraction surface or the interface between the electrode layer and the organic compound layer.

In order to solve the problem of total reflection, there has been proposed an organic EL display device in which a total reflection avoiding layer made up of a set of a plurality of microlenses is formed in an area corresponding to a pixel area (see Patent Document 1). ).
However, in this case, when the pixel region is arranged at a position away from the center of the lens, there is a problem that light cannot be extracted.
In addition, an electro-optical device has been proposed in which a lens-shaped light scattering layer is formed facing an opening region of each electro-optical element (see Patent Document 2).
However, when the light scattering layer is formed into a lens shape, there is a problem that a light collecting function as a lens cannot be obtained sufficiently.
Further, the substrate includes a substrate, a transparent electrode provided on the substrate, an organic EL layer, and a reflective electrode, and the substrate has a first surface and a second surface having irregularities, and a first surface of the support And an organic EL element having a high refractive index layer in contact with a transparent electrode, and the high refractive index layer has a convex microlens structure (see Patent Document 3).
However, there is a problem in that the light condensed on the lens hits the unevenness, and the light is scattered, so that the light collecting function as a lens cannot be sufficiently obtained.
Further, when light is extracted with a microlens, there is a problem that the light emitting area becomes larger than the aperture diameter of the lens and the light cannot be extracted.

JP 2004-127560 A JP 2006-201421 A JP 2008-66027 A

  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 light emitting display device having high light extraction efficiency and excellent optical characteristics.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, have obtained the following knowledge.
Conventionally, when extracting light with a microlens, for example, a model organic electroluminescence display device as shown in FIGS. 1a and 1b is known. FIG. 1 a is a conceptual diagram illustrating a configuration example of a conventional organic light emitting display device 50. FIG. 1b is a conceptual diagram showing the state of FIG. 1a viewed from the plane. The organic light emitting display device 50 is configured by arranging a hemispherical lens 22 on a position corresponding to the light emitting portion (pixel) 21. In this case, the maximum side length A of the light emitting portion (pixel) 21 is smaller than the diameter φ of the hemispherical lens (for example, A / φ = 0.5), and the light emitting portion (pixel) 21 is the hemispherical lens 22. When arranged near the central axis (the optical axis parallel to the normal of the laminated surface of the organic light emitting display device through the center of the hemispherical lens), the light is emitted from the light emitting section (pixel) 21 with a light extraction efficiency of 90% or more. Light can be extracted (FIG. 1c). Here, the ratio of the total light emitted up to the air and the light emitted from the light emitting unit (pixel) 21 is defined as the light extraction efficiency.
However, in this case, as the size of the light emitting portion (pixel) increases, light cannot be taken out steeply, and depending on the structure of the organic light emitting display device, a hemispherical lens is provided rather than a hemispherical lens. There is a possibility that the light extraction efficiency is higher in the absence state (see FIG. 1d). In FIG. 1c and FIG. 1d, m = 1 represents a system of experimental results in an organic electroluminescent device having a primary microcavity structure. Further, m = 2 represents a system of experimental results in an organic electroluminescent device having a secondary microcavity structure. Further, m = 3 represents a system of experimental results in an organic electroluminescent device having a tertiary microcavity structure. Moreover, NoMC has shown the system of the experimental result in the organic electroluminescent apparatus which does not have a microcavity structure.
For example, in FIG. 1d, when the size of the light emitting portion (pixel) becomes large and exceeds A / φ = 0.5, the light extraction efficiency decreases sharply. In particular, in the system where m = 1, A / φ When it exceeds 0.7, there is a possibility that an adverse effect that the light extraction efficiency is lower than that in a state where no lens is arranged may occur.
FIG. 1c is a diagram illustrating simulation results of light extraction efficiency in the organic electroluminescent display device in a state where a lens is provided and in the organic electroluminescent display device in a state where no lens is provided. FIG. 1d shows a change in the light extraction efficiency of the organic electroluminescence display device with the lens provided when the light extraction efficiency in the organic electroluminescence display device with no lens is 1 in FIG. 1c. It is a figure which shows the simulation result which shows transition of.

In addition, FIG. 2 shows a light distribution of light incident on the lens from each organic electroluminescence display device of m = 1 to 3 and NoMC. FIG. 2 shows the radiation intensity (W / St) at a radiation angle of 0 degrees when the light emitted from the light emitting portion changes the radiation angle to the light extraction surface with respect to the normal line of the organic electroluminescent display device laminate surface. .) Is obtained from the change in intensity (au) when standardized.
As shown in FIG. 2, in the organic light emitting display device having a microcavity structure, the energy of light emitted from the light emitting part of the organic light emitting display device decreases as the order of the microcavity decreases. It is inferred that the radiation angle is concentrated at a low angle. In addition, in an organic light emitting display device that does not have a microcavity structure, it is presumed that the energy of light emitted from the light emitting portion of the organic light emitting display device is the highest at a high angle.

As described above, in the organic light emitting display device, it is presumed that an appropriate lens structure is greatly changed and a light distribution (a light angle distribution) is largely changed depending on the structure design.
In addition, the results of FIGS. 1c and 1d show that the light extraction efficiency by the lens is improved as the pixel size increases as the light having a low emission angle with respect to the normal of the stacked surface in the organic light emitting display device increases. It is inferred that the effect cannot be obtained.
These causes are considered as follows.

First, an organic electroluminescence display device having a configuration without a hemispherical lens will be considered. FIG. 3a is an explanatory view showing an outline of an organic light emitting display device having a configuration without a hemispherical lens. In FIG. 3a, the organic light emitting display device 60 can extract only light having a total reflection angle or less because there is a difference in interlayer refractive index including the air layer. Therefore, the organic light emitting display device having a light distribution with a large amount of light having a low emission angle with respect to the normal of the stacked surface in the organic light emitting display device has high light extraction efficiency.
However, in the organic light emitting display device 60 having a configuration without a hemispherical lens, light is emitted from the light emitting layer even when the element is designed to have a primary microcavity structure (m = 1). 40% or more of the light to be confined in the light emitting part (pixel) 21. In addition, when the element design is performed so as to have a tertiary microcavity structure (m = 3) and when the element design is performed using a structure not having a microcavity (NoMC), about 70% of light is emitted. It is confined in the light emitting part (pixel) 21.

Next, an organic electroluminescence display device having a configuration in which a hemispherical lens is arranged on the light extraction surface will be examined. FIG. 3B is an explanatory view showing an outline of an organic light emitting display device according to an example of a configuration in which a hemispherical lens is arranged on a light extraction surface.
The light emitting point of the light emitting unit (pixel) 21 in the organic light emitting display device 70 of FIG. In some cases (see, for example, FIG. 3c), the angle of the light emitted from the light emitting unit (pixel) 21 with respect to the optical axis of the hemispherical lens 22 at the position where the light is incident on the hemispherical lens 22 regardless of the radiation angle. Element structure having a primary to tertiary microcavity structure (m = 1 to 3) and an element not having a microcavity structure In any of the configurations (NoMC), 90% or more of light can be extracted. In particular, as shown in the range of the maximum side length A / lens diameter φ of 0.5 or less in FIG. Next microcavity structure And an organic electroluminescence display device having a light extraction efficiency three times or more than that of the organic electroluminescence display device 60 having a configuration without a hemispherical lens. it can.

However, as described above, when the size of the light emitting unit (pixel) 21 is increased, it is difficult to extract light with a desired efficiency. Here, the extraction of light in the light emitting part (pixel) 21 in which the light emitting point is arranged at a position away from the central axis of the hemispherical lens 22 in the light emitting part (pixel) 21 will be considered.
FIG. 3d is an explanatory view showing an outline of an organic light emitting display device according to another configuration example in which a hemispherical lens is arranged.
In FIG. 3 d, the light emitting points in the light emitting portions (pixels) 21 arranged in the organic light emitting display device 80 are arranged at positions away from the central axis of the hemispherical lens 22. Of the light emitted from the light emitting unit (pixel) 21, the angle that intersects the line parallel to the central axis direction of the hemispherical lens 22 is larger than the total reflection critical angle, and cannot be extracted when the hemispherical lens 22 is not disposed. By arranging the hemispherical lens 22, the angle of the light with respect to a line parallel to the central axis direction of the hemispherical lens 22 at a position where the hemispherical lens 22 is incident can be reduced.
However, when the hemispherical lens 22 is arranged, light having a small angle (light with a low radiation angle) intersecting with a line parallel to the central axis direction of the hemispherical lens 22 that has been taken out when the hemispherical lens 22 is not arranged becomes hemispherical. Since the angle with respect to the optical axis of the hemispherical lens 22 at the position where the hemispherical lens 22 is incident is increased, the light that can be efficiently extracted without the hemispherical lens 22 being arranged cannot be extracted in reverse. It becomes like this.
Therefore, in the case where the hemispherical lens 22 is not disposed when the light emitting point shown as the light emitting unit (pixel) 21 disposed in the organic light emitting display device 80 is disposed at a position away from the central axis of the hemispherical lens 22. There is a high possibility that light having a small angle with respect to a line parallel to the central axis direction of the hemispherical lens 22 that has been extracted cannot be extracted.
Therefore, in an organic electroluminescence display device that includes a light emitting portion (pixel) 21 at a position away from the central axis of the hemispherical lens 22 and has a large ratio of the maximum side length A and the diameter φ of the hemispherical lens, It is presumed that a steep decrease in the light extraction efficiency as shown in FIG. 1c and FIG.
Practical organic electroluminescence display devices are required to be thin and have high performance, and a sufficiently large lens cannot be used with respect to the size of the light emitting portion (pixel) 21. It is considered that the present situation is that high light extraction efficiency is not obtained in the apparatus.

In order to improve the current state of the light extraction efficiency, the present inventors have further studied, and if a light scattering layer is disposed between the light emitting portion (pixel) and the hemispherical lens, the light is greatly improved. The extraction efficiency is improved, and the light extraction efficiency is drastically reduced in both the element configuration having a primary to tertiary microcavity structure (m = 1 to 3) and the element configuration not having a microcavity structure (NoMC). It was found that it can be suppressed.
That is, in an organic light emitting display having such a light scattering layer, for example, as shown in FIG. 4A, when the light emitting part (pixel) 21 is arranged near the central axis of the hemispherical lens 22, the light emitting part The light emitted from the light emitting layer included in the (pixel) 21 is scattered by the light scattering layer 23, and can be emitted from the hemispherical lens 22 to the air layer regardless of the converted angle. High light extraction efficiency can be maintained.
In addition, as shown in FIG. 4 b, when the light emitting unit (pixel) 21 is arranged at a position away from the central axis of the hemispherical lens 22, light emitted from the light emitting layer included in the light emitting unit (pixel) 21 is emitted. Similarly, by being scattered by the light scattering layer 23, the incident angle with respect to the hemispherical lens 22 is changed, and intersects with a line parallel to the central axis direction of the hemispherical lens 22 that has been difficult to extract so far. Most of the light having a small angle can be converted to light having a large angle as light close to Lambertian, which contributes to the improvement of the light extraction efficiency.

The present invention is based on the above knowledge, and means for solving the above problems are as follows. That is,
<1> An organic electroluminescent element having at least a light emitting layer, a hemispherical lens disposed on the light extraction surface side, and light emitted from the light emitting layer is scattered between the light emitting layer and the hemispherical lens. An organic electroluminescence display device comprising a light scattering layer.
<2> The organic electroluminescence display device according to <1>, wherein the light scattering layer is any one of a fine particle scattering layer and a concavo-convex structure layer having irregularities arranged periodically or aperiodically.
<3> The light scattering layer is disposed in a region corresponding to the inner peripheral edge side of the hemispherical lens on the surface on which the hemispherical lens is supported, and has an opening in a circular region centered on the central axis of the hemispherical lens The organic electroluminescence display device according to any one of <1> to <2>, which is an annular layer.
<4> The contact area between the light scattering layer and the hemispherical lens on the support surface on which the hemispherical lens is supported is an area of 15% to 95%, where the area in the supported region of the hemispherical lens is 100%. <1> to the organic electroluminescence display device according to any one of <3>.
<5> The above <1> to <4>, wherein an area of a pixel formed on the light extraction surface is 0.3 times or more with respect to a minimum area in a rectangular region surrounding the support surface supporting the hemispherical lens. The organic electroluminescent display device according to any one of the above.
<6> A transflective electrode disposed on the light extraction surface side, and a reflective electrode layer disposed on a surface opposite to the transflective electrode via the light emitting layer, and emits light from the light emitting layer. The organic electroluminescence display device according to any one of <1> to <5>, further including a microcavity structure that causes light to interfere between the semi-transmissive reflective electrode and the reflective electrode to be emitted from the light extraction surface It is.
<7> Any one of the items <1> to <5>, including a transmissive electrode disposed on a light extraction surface side and a reflective electrode layer disposed on a surface opposite to the transmissive electrode via a light emitting layer. It is an organic electroluminescent display apparatus of description.
<8> When the microcavity structure is primary, the radius of the hemispherical lens is R, and the radial width of the hemispherical lens of the light scattering layer is a, the relationship between a and R is It is an organic electroluminescent display apparatus as described in said <6> which satisfy | fills the relationship of following formula and 0.3 <= a / R <= 0.5.
<9> When the microcavity structure is secondary, the radius of the hemispherical lens is R, and the radial width of the hemispherical lens of the light scattering layer is a, the relationship between a and R is It is an organic electroluminescent display apparatus as described in said <6> which satisfy | fills the relationship of following formula and 0.3 <= a / R <= 0.6.
<10> When the microcavity structure is tertiary, the radius of the hemispherical lens is R, and the radial width of the hemispherical lens of the light scattering layer is a, the relationship between a and R is It is an organic electroluminescent display apparatus as described in said <6> satisfy | filling the relationship of following Formula and 0.4 <= a / R <= 0.7.
<11> When the radius in the hemispherical lens is R and the radial width of the hemispherical lens in the light scattering layer is a, the relationship between a and R is expressed by the following formula: 0.4 ≦ a / It is an organic electroluminescent display apparatus as described in said <7> which satisfy | fills the relationship of R <= 1.
<12> The organic electroluminescence display device according to any one of <1> to <11>, wherein the light scattering layer is formed integrally with the hemispherical lens.
<13> The organic electroluminescence display device according to any one of <1> to <12>, wherein the light scattering layer is formed separately from the hemispherical lens.
<14> The organic electroluminescence display device according to any one of <1> to <13>, which has a top emission type structure.
<15> The organic electroluminescence display device according to any one of <1> to <14>, having a bottom emission type structure.

  ADVANTAGE OF THE INVENTION According to this invention, the said various problems in the past can be solved, the said objective can be achieved, an organic electroluminescent display apparatus which has high light extraction efficiency and has the outstanding optical characteristic can be provided.

FIG. 1 a is a conceptual diagram illustrating a configuration example of a conventional organic light emitting display device 50. It is a conceptual diagram which shows the state which looked at FIG. 1a from the plane. FIG. 1C is a diagram illustrating simulation results of light extraction efficiency in an organic light emitting display with a lens and an organic light emitting display without a lens. FIG. 1d shows a change in the light extraction efficiency of the organic light emitting display device with the lens arranged when the light extraction efficiency in the organic light emitting display device with no lens is 1 in FIG. 1c. It is a figure which shows the simulation result which shows. It is a figure which shows the light distribution of the light which injects into a lens from each organic electroluminescent display apparatus of m = 1-3, NoMC. FIG. 3a is an explanatory view showing an outline of an organic light emitting display device having a configuration without a hemispherical lens. FIG. 3B is an explanatory view showing an outline of an organic light emitting display device according to an example of a configuration in which a hemispherical lens is arranged on a light extraction surface. FIG. 3c is an explanatory diagram showing an outline of an organic light emitting display device according to another configuration example in which a hemispherical lens is provided. FIG. 3d is an explanatory view showing an outline of an organic light emitting display device according to another configuration example in which a hemispherical lens is arranged. FIG. 4A is an explanatory diagram illustrating an outline of an organic light emitting display according to an embodiment of the present invention. FIG. 4b is an explanatory view showing an outline of an organic light emitting display device according to another embodiment of the present invention. FIG. 5a is a schematic cross-sectional view for explaining the outline of the organic light emitting display device 1 of the present invention. FIG. 5B is a schematic plan view for explaining the relationship between the radius R in the hemispherical lens 22 and the radial width a of the hemispherical lens 22 in the light scattering layer 23 shown in FIG. 5A. FIG. 6A is a graph showing a transition of light extraction efficiency in an organic light emitting display having a primary microcavity structure. FIG. 6B is a graph showing a transition of light extraction efficiency in an organic light emitting display having a secondary microcavity structure. FIG. 6c is a graph showing transition of light extraction efficiency in an organic light emitting display device having a tertiary microcavity structure. FIG. 6d is a graph showing the transition of light extraction efficiency in an organic light emitting display device that does not have a microcavity structure. FIG. 6e is a diagram showing the transition of the light extraction efficiency when focusing on the system of a / R = 0.4. FIG. 7 a-1 is a diagram showing a transition of front luminance in an organic light emitting display having a primary microcavity structure. FIG. 7A-2 is a diagram illustrating the transition of the front luminance of the system with a / R = 0.3 to 0.5 and the system with m = 1 lens only in FIG. 7A-1. FIG. 7 b-1 is a diagram showing a transition of front luminance in an organic light emitting display having a secondary microcavity structure. FIG. 7 b-2 is a diagram showing the transition of the front luminance of the system with a / R = 0.3 to 0.6 and the system with m = 2 lens only in FIG. 7 b-1. FIG. 7 c-1 is a diagram showing a transition of front luminance in an organic light emitting display device having a tertiary microcavity structure. FIG. 7c-2 is a diagram in which the transition of the front luminance of the system with a / R = 0.4 to 0.7 and the system with m = 3 lens only in FIG. 7c-1 is extracted and shown. FIG. 7 d-1 is a diagram showing a transition of front luminance in an organic light emitting display device that does not have a microcavity structure. FIG. 7d-2 is a diagram extracting and showing the transition of the front luminance of the system with a / R = 0.4 to 1 and the system with m = NoMC lens only in FIG. 7d-1. FIG. 8A is a diagram showing a transition of front luminance when focusing on the system of a / R = 0.4 in Example 1 and Comparative Example 1. FIG. FIG. 8B is a diagram illustrating the transition of the front luminance when focusing on the system of a / R = 0.4 in Example 2 and Comparative Example 2. FIG. 8c is a diagram showing the transition of the front luminance when focusing on the system of a / R = 0.4 in Example 3 and Comparative Example 3. FIG. 8d is a diagram showing the transition of the front luminance when focusing on the system of a / R = 0.4 in Example 4 and Comparative Example 4. FIG. 9 a is an explanatory diagram showing an outline of an organic light emitting display device according to a comparative example. FIG. 9b is a diagram for explaining light extraction in FIG. 9a. FIG. 9C is an explanatory diagram for explaining the outline of the organic light emitting display device according to the bottom emission type embodiment. FIG. 9d is an explanatory diagram when FIG. 9a is viewed from a plane. FIG. 10 is a diagram illustrating an example of a state in which lenses are arranged on RGB three pixels. FIG. 11 is a diagram showing another example of a state in which lenses are arranged on RGB three pixels. FIG. 11 is a diagram showing another example of a state in which lenses are arranged on RGB three pixels. FIG. 13 is a diagram showing the maximum side length A of one side when the pixel is rectangular. FIG. 14A is an explanatory diagram for explaining an outline of an organic light emitting display device according to a top emission type embodiment. FIG. 14B is an explanatory diagram when FIG. 14A is viewed from a plane. FIG. 15 is a diagram showing an aperture ratio (B / M) of the organic light emitting display device of the present invention. FIG. 16 is a schematic cross-sectional view showing an example of the organic light emitting display device of the present invention. FIG. 17 is a schematic cross-sectional view showing another example of the organic electroluminescent device of the present invention.

(Organic light emitting display)
The organic electroluminescent display device of the present invention includes an organic electroluminescent element having at least a light emitting layer, a hemispherical lens disposed on a light extraction surface side, and the light emitting layer between the light emitting layer and the hemispherical lens. A light scattering layer that scatters the emitted light, and other members as necessary.

<Light scattering layer>
The light scattering layer is not particularly limited as long as it scatters light emitted from the light emitting layer, and can be appropriately selected according to the purpose. A concavo-convex structure layer having concavo-convex periodically arranged is preferable.

The configuration of the organic electroluminescence display device including the light scattering layer is not particularly limited as long as the configuration includes the light scattering layer between the light emitting layer and the hemispherical lens, and is appropriately selected depending on the purpose. can do.
For example, the light scattering layer and the hemispherical lens may be integrally formed, and in this case, the light scattering layer and the light scattering layer on the substrate as a light extraction surface of light emitted from the light emitting layer, The structure which has a hemispherical lens in this order is mentioned. Further, the light scattering layer and the hemispherical lens may be formed as separate bodies. In this case, the light scattering layer and the substrate are provided on the functional layer on the light extraction surface side of the organic electroluminescent element. And a configuration having the hemispherical lens in this order.

-Fine particle-containing layer-
The fine particle-containing layer is configured as a layer containing fine particles.
The fine particles are not particularly limited and may be appropriately selected depending on the intended purpose. For example, TiO2 fine particles (refractive index: 2.6), ZnO fine particles (refractive index: 1.95), ZnS fine particles (refractive Ratio: 2.37), ZrO fine particles (refractive index: 2.4) and the like are preferable.
The mass average particle diameter of the fine particles is not particularly limited, but is preferably 100 nm to 800 nm.

Although there is no restriction | limiting in particular as a refractive index of the binder of the fine particle content layer containing the said fine particle, 1.54-2.2 are preferable, 1.7-2.0 are more preferable, 1.75-1. 85 is particularly preferred.
If the refractive index is less than 1.54, the light emitted from the light emitting portion is totally reflected and there is little light entering the scattering layer, so there is no sufficient light scattering and light cannot be extracted. If the ratio exceeds 2.2, more light may be reflected by the scattering layer and not enter the scattering layer. In addition, since the amount of light that is confined in the scattering layer having a high refractive index and is not emitted outside the scattering layer increases, the light may not be extracted.
There is no restriction | limiting in particular as thickness of the said fine particle content layer, Although it can select suitably according to the objective, It is preferable that it is less than 1.0 micrometer.
When the thickness of the fine particle-containing layer is 1.0 μm or more, backscattering increases, which may affect the light extraction effect. Moreover, multiple scattering increases, and light may be guided into the scattering film without necessity.

  There is no restriction | limiting in particular as a formation method of the said fine particle content layer, According to the objective, it can select suitably, For example, the method etc. which apply | coat and dry the composition solution containing the said fine particle with a spin coater are mentioned.

--- Uneven layer ---
The concavo-convex layer is not particularly limited as long as it includes a concavo-convex structure, but a layer configured so that the concavo-convex structure is planarized by a planarizing film is preferable.
The concavo-convex structure may be formed aperiodically, but is preferably formed periodically.
Although there is no restriction | limiting in particular as the period (pitch space | interval P) of the said uneven structure, 0.7 micrometer-2 micrometers are preferable, and 1.4 micrometer-1.8 micrometers are more preferable.
There is no restriction | limiting in particular as the height in the convex part of the said uneven structure, 0.35 micrometer-2 micrometers are preferable, and 0.7 micrometer-1.8 micrometers are more preferable.
There is no restriction | limiting in particular as the width | variety in the convex part of the said uneven structure, 0.3 micrometer-1.6 micrometers are preferable, and 0.6 micrometer-1.5 micrometers are more preferable.

There is no restriction | limiting in particular as a formation method of the said uneven structure, According to the objective, it can select suitably, For example, it can form by well-known lithography method, the etching method, and the imprint method.
Moreover, there is no restriction | limiting in particular as said uneven structure, It is preferable to form with transparent resist materials, such as PMMA (polymethylmethacrylate), and to coat the surface of the said uneven structure with metal materials, such as Cr metal.
Moreover, you may provide the base layer which consists of materials, such as magnesium fluoride (refractive index: 1.37), as a base which distributes the said uneven structure.

The material for the planarizing film is not particularly limited, but a high refractive material is preferable.
The high refractive material is not particularly limited, but SiON, Si ₃ N ₄ and a mixed material of SiON and Si ₃ N ₄ are preferable.
Although there is no restriction | limiting in particular as the refractive index of the light of the said high refractive material, 1.6-2.0 are preferable and 1.7-1.9 are more preferable.

There is no restriction | limiting in particular as a shape of the said light-scattering layer, For example, it can be set as a circular shape and an annular | circular shaped layer.
Moreover, there is no restriction | limiting in particular as arrangement | positioning of the said light-scattering layer, It can arrange | position in arbitrary aspects on a pixel.
The light scattering layer is shaped and arranged in a region corresponding to the inner peripheral side of the hemispherical lens on the surface on which the hemispherical lens is supported, and centered on the central axis of the hemispherical lens. An annular layer having an opening in a circular region is preferred.
In such an aspect, light emitted from pixels arranged around the central axis of the hemispherical lens having high light extraction efficiency is incident on the hemispherical lens, and excellent light extraction efficiency is maintained. The light scattering layer scatters the light emitted from the pixels arranged in the region corresponding to the inner peripheral edge of the hemispherical lens having a low light extraction efficiency, thereby confining the light by the hemispherical lens. It can suppress and can obtain the outstanding light extraction efficiency.

Here, a specific configuration of the light scattering layer will be described with reference to FIG. In FIG. 5 b, R indicates the radius of the hemispherical lens 22, and a indicates the width of the light scattering layer 23 in the radial direction of the hemispherical lens 22.
As shown in FIG. 5 b, the light scattering layer 23 is formed as an annular layer, and is disposed corresponding to a region corresponding to the inner peripheral side of the hemispherical lens.
However, the width a of the light scattering layer 23 in the radial direction of the hemispherical lens 22 is not particularly limited and can be appropriately selected according to the purpose, and is the same length as the radius R of the hemispherical lens 22. May be selected. In this case, the light scattering layer 23 is a circular layer.

Further, the specific arrangement of the light scattering layer is not particularly limited, but the contact area between the light scattering layer and the hemispheric lens on the support surface on which the hemispherical lens is supported is The area in the supported region is preferably 100%, so that the area is 15% to 95%, more preferably 30% to 90%, and more preferably 50% to 85%. It is particularly preferable to arrange it so as to have an area.
If it is less than 15%, the amount of scattered light is small, and in particular, an effect of sufficient light extraction efficiency may not be obtained in an organic electroluminescence display device having a low-order microcavity structure (m = 1). If it exceeds 95%, most of the light is scattered, the amount of light emitted to the front is small, and the front luminance of the light emitted from the lens becomes insufficient.

Further, the area of the pixels formed on the light extraction surface is preferably 0.3 times or more with respect to the minimum area in the rectangular region surrounding the support surface that supports the hemispherical lens, and 0.4 times to 0.9 times is more preferable, and 0.5 times to 0.8 times is particularly preferable.
If it is less than 0.3 times, if there is a scattering layer, the front brightness may be reduced due to scattering. If it exceeds 0.9 times, the light extraction efficiency and front brightness will be reduced in the lens or lens and scattering layer. The effect for achieving both may be reduced.
Here, the area of the pixels formed on the light extraction surface corresponds to the area of B, which is a region where the pixels shown in FIG. 15 are arranged, and the rectangular area surrounding the support surface that supports the hemispherical lens. The minimum area in the shape region corresponds to the area M shown in FIG.
In this specification, the aperture ratio is represented by the ratio of the area of B to the area of M, B / M.

<Structure>
The structure of the organic electroluminescent display device of the present invention is not particularly limited and can be appropriately selected according to the purpose. In the combination of the selected hemispherical lens and the light scattering layer, the light extraction efficiency, the front luminance is obtained. It can be set as the structure which optimizes.

  Here, there is no restriction | limiting in particular as a structure in the said organic electroluminescent display apparatus, According to the objective, it can select suitably, For example, (1) Electrode structure of the light emission side in an organic electroluminescent display part, (2) Examples include an optical length of a microcavity structure, and (3) a bottom emission type or a top emission type.

As the electrode on the light emission side of the organic EL display unit (1), in the bottom emission type, a transparent electrode (for example, ITO) having a reflectance as viewed from the light emitting layer of 10% or less, or a reflectance as viewed from the light emitting layer is used. A transflective electrode (for example, an Ag electrode) exceeding 10% can be used. If a transparent electrode is used as the anode, the microcavity structure cannot be formed because the reflection of light is weak. When a transflective electrode is used as the anode, a microcavity structure can be formed.
In the top emission type, a microcavity structure is formed by using a transflective electrode with a reflectance exceeding 10% as viewed from the light emitting layer as an electrode (anode) on the light emission side.

The optical length of the microcavity structure (2) can be appropriately adjusted by changing the thickness of the organic compound layer between the anode and the cathode constituting the organic electroluminescent element. Here, there is no restriction | limiting in particular as said organic compound layer, According to the objective, it can select suitably, For example, a hole transport layer, a hole injection layer, a light emitting layer, an electron transport layer, an electron injection layer, etc. are mentioned. .
Here, the macrocavity structure means a structure in which a light-transmitting side transflective layer and a light-exiting reflective layer interfere with each other, and a semi-transmissive reflective electrode disposed on the light extraction surface side; A reflective electrode layer disposed on the opposite side of the transflective electrode through the light emitting layer, and light emitted from the light emitting layer is interposed between the transflective electrode and the reflective electrode. And a structure in which the light is emitted from the light extraction surface.
Further, as a structure not having the microcavity structure, there is a structure having a transmissive electrode disposed on the light extraction surface side and a reflective electrode layer disposed on the surface opposite to the transmissive electrode through the light emitting layer. Can be mentioned.

The optical length (optical distance) L of the microcavity structure is represented by L = 2 × Σn _i d _i (where i represents an integer from 1 to i in the number of layers) and a phase shift due to reflection, It is represented by the sum of the products of the thickness d of each layer formed between the cathodes and the refractive index n of the layer.
The optical length L is related to the emission wavelength λ by the optical length L (λ) = mλ (m = 1: 1, m = 2: secondary, m = 3: 3rd), and the optical length L (λ) is represented by the following mathematical formula.
Where L (λ) is the optical length [= 2Σn _j d _j + ΣABS (φmiλ / 2π)], λ is the emission wavelength, i is a suffix indicating the metal reflective layer, and j is other than the metal reflective layer. A suffix indicating a layer (an organic layer, a dielectric layer, etc.) between metal layers is represented.

When the microcavity structure is primary, the optical length L (λ) is 1λ (where λ represents the emission wavelength), and the minimum optical that is a condition for strengthening the light that round-trips between the metal reflective layers. Means long.
The microcavity structure is second order, the optical length L (λ) is 2λ (where λ represents the emission wavelength), and the minimum optical that is a condition for strengthening the light that round-trips between the metal reflective layers. It means that the optical length is the second shortest from the longest.
When the microcavity structure is third order, the optical length L (λ) is 3λ (where λ represents the light emission wavelength), and the minimum optical that is a condition for strengthening the light that round-trips between the metal reflective layers. It means that the optical length is the third shortest from the longest.

<Organic electroluminescent device>
The organic electroluminescent element has at least a light emitting layer between an anode and a cathode, and may have a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, etc., if necessary. Each of these layers may have other functions. Various materials can be used for forming each layer.
The organic electroluminescent element may be red (R), green (B), or blue (B).
As a configuration of such a pixel, for example, as described in “Monthly Display”, September 2000, pages 33 to 37, the light emitting layer is made to emit light corresponding to red, green, or blue, respectively. A known structure such as a three-color light emitting method in which a pixel as a light emitting layer that emits light is formed and any one of these red, green, and blue pixels is arranged can be applied.

-Anode-
The anode supplies holes to a hole injection layer, a hole transport layer, a light emitting layer, and the like, and a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. The material preferably has a work function of 4 eV or more. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, and indium tin oxide (ITO), or metals such as gold, silver, chromium, and nickel, and these metals and conductive metal oxides. Inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO, preferably conductive metals It is an oxide, and ITO is particularly preferable from the viewpoint of productivity, high conductivity, transparency, and the like.
There is no restriction | limiting in particular in the thickness of the said anode, Although it can select suitably by material, 10 nm-5 micrometers are preferable, 50 nm-1 micrometer are more preferable, 100 nm-500 nm are still more preferable.

As the anode, a layer formed on a soda-lime glass, non-alkali glass, a transparent resin substrate or the like is usually used. When glass is used, 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 coatings, such as a silica.
The thickness of the substrate is not particularly limited as long as it is sufficient to maintain mechanical strength, but when glass is used, it is preferably 0.2 mm or more, and more preferably 0.7 mm or more.

  A barrier film can also be used as the transparent resin substrate. The barrier film is a film in which a gas impermeable barrier layer is provided on a plastic support. As the barrier film, a film in which silicon oxide or aluminum oxide is vapor-deposited (Japanese Patent Publication No. 53-12953, Japanese Patent Laid-Open No. 58-217344), an organic-inorganic hybrid coating layer (Japanese Patent Laid-Open No. 2000-323273, JP-A-2004-25732), those having an inorganic layered compound (JP-A-2001-205743), laminates of inorganic materials (JP-A-2003-206361, JP-A-2006-263389), organic Layer and inorganic layer laminated alternately (Japanese Patent Laid-Open No. 2007-30387, US Pat. No. 6,436,645, Affinito et al., Thin Solid Films 1996, pages 290-291), organic layer and inorganic layer continuously A laminate (US Patent Application Publication No. 2004-46497) and the like can be mentioned.

  Various methods are used for the production of the anode. For example, in the case of ITO, electron beam method, sputtering method, resistance heating vapor deposition method, chemical reaction method (sol-gel method, etc.), dispersion of indium tin oxide A film is formed by a method such as application of an object. The anode can be subjected to cleaning or other processing to lower the driving voltage of the display device or to increase the light emission efficiency. For example, in the case of ITO, UV-ozone treatment is effective.

-Cathode-
The cathode supplies electrons to an electron injection layer, an electron transport layer, a light emitting layer, and the like. Adhesion between the cathode and adjacent layers such as an electron injection layer, an electron transport layer, and a light emitting layer, ionization potential, and stability It is selected in consideration of sex and the like.
As the material of the cathode, a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. Specific examples thereof include alkali metals (for example, Li, Na, K, etc.) or fluorides thereof, Alkaline earth metals (eg Mg, Ca, etc.) or fluorides thereof, gold, silver, lead, aluminum, sodium-potassium alloys or mixed metals thereof, lithium-aluminum alloys or mixed metals thereof, magnesium-silver alloys or those thereof And a rare earth metal such as indium and ytterbium. Among these, a material having a work function of 4 eV or less is preferable, and aluminum, a lithium-aluminum alloy or a mixed metal thereof, a magnesium-silver alloy or a mixed metal thereof is particularly preferable.

There is no restriction | limiting in particular in the thickness of the said cathode, Although it can select suitably by material, 10 nm-5 micrometers are preferable, 50 nm-1 micrometer are more preferable, 100 nm-1 micrometer are still more preferable.
For the production of the cathode, for example, an electron beam method, a sputtering method, a resistance heating vapor deposition method, a coating method or the like is used, and a metal can be vapor-deposited alone or two or more components can be vapor-deposited simultaneously. Furthermore, a plurality of metals can be vapor-deposited simultaneously to form an alloy electrode, or a pre-adjusted alloy may be vapor-deposited.
The sheet resistance of the anode and cathode is preferably low, and is preferably several hundred Ω / □ or less.

-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.

-Hole injection layer, hole transport layer-
The material of the hole injection layer and 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. If it is, there will be no restriction | limiting in particular, According to the objective, it can select suitably.
Examples of the material for the hole injection layer and the hole transport layer include carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamines. Derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, polysilanes Examples thereof include (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 and 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. Good.
As a method for forming the hole injection layer and 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 casting method, a dip method). Coating method). 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 thicknesses of the hole injection layer and the hole transport layer are not particularly limited and may be appropriately selected depending on the 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 still more preferable. .

-Electron injection layer, electron transport layer-
As a material for the electron injection layer and the electron transport layer, any material may be used as long as it has any one of the function of injecting electrons from the cathode, the function of transporting electrons, and the function of blocking holes injected from the anode. There is no restriction | limiting, According to the objective, it can select suitably.
Examples of the material for the electron injection layer and 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 And various metal complexes represented by These may be used individually by 1 type and may use 2 or more types together.

The electron injection layer and the electron transport layer may have a single layer structure made of one or more of the materials described above, or may have a multilayer structure made of a plurality of layers having the same composition or different compositions.
As a method for forming the electron injection layer and 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.) ) 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, 10 nm-500 nm are still more preferable.

<Hemispherical lens>
The hemispherical lens has a function of controlling an optical path of light emitted from the light emitting layer provided on the light extraction surface via the scattering layer.
Examples of the light extraction surface include a glass substrate in the bottom emission type. The top emission type includes a barrier layer.

The hemispherical lens is not particularly limited in shape, arrangement, size, material, and the like, and can be appropriately selected according to the purpose. Examples of the shape include a spherical shape, an aspherical shape, an elliptical shape, Examples include trapezoidal shapes.
The hemispherical lens may be formed as a microlens array including a plurality of the hemispherical lenses. In this case, examples of the arrangement of the hemispherical lenses include a square lattice shape and a honeycomb shape.
Examples of the material of the hemispherical lens include transparent resin, glass, transparent crystal, and transparent ceramic.
As the size of the hemispherical lens, in the case of a hemispherical lens, the effective diameter is preferably 10 μm to 1,000 μm, and more preferably 20 μm to 200 μm.
Moreover, when the distance between the light emitting layer and the hemispherical lens is d, the d is not particularly limited, but preferably does not exceed 200 μm, and more preferably does not exceed 20 μm.
When d exceeds 200 μm, light with a high emission angle emitted from the light emitting unit cannot enter the corresponding scattering layer or the corresponding lens, which causes pixel bleeding.

There is no restriction | limiting in particular as a manufacturing method of the said lens, According to the objective, it can select suitably, For example, the inkjet method, the imprint method, the photolithographic method etc. are mentioned.
In the imprint method, for example, after a composition containing a release agent and a UV curable resin is applied on a transparent mold, the transparent mold is pressure-bonded on an organic EL element, irradiated with UV light, and then released. By doing so, a lens can be formed on the organic EL element.

<Other members>
-Barrier layer-
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 depending on 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 especially preferable. If the thickness of the barrier layer is less than 5 nm, the barrier function for preventing the permeation of oxygen and moisture in the air may be insufficient. If the thickness exceeds 1,000 nm, the light transmittance decreases and the transparency is reduced. May be damaged.
As for the optical properties of the barrier layer, the light transmittance is preferably 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, a vacuum evaporation method, etc. are mentioned.
The barrier layer can be applied as a sealing layer or a cocoon oil layer.

-Board-
The substrate may be appropriately selected in its shape, structure, size, etc. In general, the substrate is preferably plate-shaped. The structure of the 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. The 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 light emitting 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 for 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 coatings, 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.

  Here, FIG. 16 is a schematic cross-sectional view showing a bottom emission type organic light emitting display device which is an example of the organic light emitting display device of the present invention. FIG. 17 is a schematic cross-sectional view showing a top emission type organic electroluminescent display device which is an example of the organic electroluminescent display device of the present invention.

A bottom emission type organic electroluminescent display device 100 of FIG. 16 is provided on a glass substrate 1 with an organic electroluminescent display 101 (anode 2, hole injection layer 3, hole transport layer 4, light emitting layer 5, electron transport layer 6 and electrons). A lens 9 is formed on the glass substrate 1 as the light extraction surface, having an injection layer 7 and a cathode 8).
A top emission type organic electroluminescent display device 200 of FIG. 17 is formed on a glass substrate 1 with an organic electroluminescent display 201 (cathode 8, hole injection layer 3, hole transport layer 4, light emitting layer 5, electron transport layer 6, electron transport layer). It has an injection layer 7 and an anode 2), a gas barrier layer 10 is formed on the cathode 8, and a lens 9 is formed on the gas barrier layer 10 as a light extraction surface.
The “light emission direction” indicates a direction in which light from the light emitting layer is emitted from the light extraction surface to the outside of the organic light emitting display device. In the case of the bottom emission type organic electroluminescent display device 100 shown in FIG. 16, as indicated by an arrow, the direction toward the lower side in parallel with the drawing as viewed from the light emitting layer 5 is shown. In the case of the top emission type organic electroluminescence display device 200 shown in FIG. 17, as indicated by an arrow, a direction upward from the light emitting layer 5 in parallel with the drawing is shown.

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

  In addition, by using a combination of a plurality of layer structures of different emission colors obtained by the above method, a planar light source having a desired emission color can be obtained. 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 display device of the present invention includes, for example, a computer, an on-vehicle display, an outdoor display, a household device, a commercial device, a household appliance, a traffic display, a clock display, a calendar display, a luminescence. It can be suitably used in various fields including cent 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.

<Evaluation of light extraction efficiency>
(Example 1 and Comparative Example 1: having a primary microcavity structure)
FIGS. 5a and 5b show calculation models of light extraction efficiency in an organic electroluminescent display device having an organic electroluminescent display unit, a light scattering layer, and a hemispherical lens. FIG. 5a is a schematic cross-sectional view for explaining the outline of the organic light emitting display device of the present invention. FIG. 5B is a schematic plan view for explaining the relationship between the radius R of the hemispherical lens 22 and the radial width a of the hemispherical lens 22 in the light scattering layer 23 shown in FIG. 5A.

As shown in FIG. 5a, the organic light emitting display device 1 is configured by arranging a light scattering layer 23 and a hemispherical lens 22 in this order on the light extraction surface side having a light emitting portion (pixel) 21. The Here, the radius of the hemispherical lens 22 is R, and the radial width of the hemispherical lens 22 in the light scattering layer 23 is a (see FIG. 5b). The organic light emitting display device 1 has a primary microcavity structure.
The organic electroluminescent display device in Example 1 was configured as described above.

  In addition, a / R, which is a ratio of a and R, was changed by 0.1 in a numerical range from 0.1 to 1, and a / R = 0.1 to a / R = 1. Use the system. In the system of a / R = 0.1 to a / R = 0.9, the light scattering layer 23 is an annular layer having an opening in a circular region centered on the central axis of the hemispherical lens 22, and a In the system of / R = 1, the light scattering layer 23 forms a circular layer.

In addition, the maximum side length of the pixel 11 having a rectangular shape in plan view is A, and the diameter of the hemispherical lens is φ (see FIG. 5A).
In Example 1, when A / φ, which is the ratio of A and φ, is changed by 0.1 within a numerical range of more than 0 and 1 or less, the light extraction efficiency is a / R = 0. It was calculated how the transition occurred in 10 systems with 1 to a / R = 1.
The light extraction efficiency of the organic electroluminescence display device 1 in the state where the hemispherical lens 22 and the light scattering layer 23 are arranged is 1.0, where the light extraction efficiency in a state where the hemispherical lens 22 and the light scattering layer 23 are not arranged is 1.0. Relatively evaluate light extraction efficiency.

The transition of the light extraction efficiency in 10 systems with a / R = 0.1 to a / R = 1 was calculated as follows.
In order to confirm the effect of the scattering layer, using the ray tracing optical system design software, the hemispherical lens refractive index n = 1.8 and the diameter φ2 mm for the model of FIG. It is assumed that the light scattering layer 23 is arranged on the light incident surface of the hemispherical lens at 0.2 mm, the refractive index n = 1.8 of the light emitting portion, and the light scattering in the light scattering layer 23 is Lambertian scattering. And perform a simulation. The organic light emitting display device has a cavity order m = 1 structure having a microcavity, and the light emitted from the light emitting unit is a light source having a photo-alignment distribution of m = 1 shown in FIG. 2, and as shown in FIG. 3b. The maximum side length A of the rectangular light emitting surface is changed by 0.2 mm in a range of 0 to 2 mm. The scattering diameter a as shown in FIG. 5b changes the proportionality factor with respect to the radius of the hemispherical lens, and the light emitted from the light-emitting portion depends on the radiation power (W) and radiation angle of the light emitted to the air through the scattering layer and the hemispherical lens. Considering the radiant intensity (W / St.), The ratio of the power of the radiated light to the air and the power of the light emitted from the light emitting part is the light extraction efficiency.

In Example 1, the organic electroluminescent display device in Comparative Example 1 was configured in the same manner as Example 1 except that the light scattering layer 23 was not provided.
The transition of the light extraction efficiency in the system of the organic light emitting display device in Comparative Example 1 was calculated as follows.
In the case where there is no scattering layer, the same software is used, and for the model of FIG. The simulation is performed assuming that the refractive index of n = 1.8. The organic light emitting display device has a cavity order m = 1 structure having a microcavity, and the light emitted from the light emitting unit is a light source having a photo-alignment distribution of m = 1 shown in FIG. 2, and as shown in FIG. 3b. The maximum side length A of the rectangular light emitting surface is changed by 0.2 mm in a range of 0 to 2 mm. Considering the radiation power (W) of the light emitted from the light emitting part through the hemispherical lens to the air and the radiation intensity depending on the radiation angle (W / St.), The power of the emitted light to the air and the light emitting part The ratio of the power of emitted light is defined as light extraction efficiency, and the radiation intensity at a radiation angle of 0 degrees is defined as front luminance.

The experimental result of the light extraction efficiency in each organic electroluminescent display device in Example 1 and Comparative Example 1 is shown in FIG. FIG. 6A is a graph showing a transition of light extraction efficiency in an organic light emitting display having a primary microcavity structure.
As shown in FIG. 6a, the organic light emitting display in Comparative Example 1 is used in all 10 systems of a / R = 0.1 to a / R = 1 in the organic light emitting display in Example 1. The light extraction efficiency is higher than that of the system (m = 1 lens only), and it is assumed that high light extraction efficiency can be obtained.
Further, among the systems of the organic electroluminescence display device in Example 1, the system with a / R = 0.1 is in a state where the hemispherical lens 22 is not arranged when A / φ exceeds 0.7. It is presumed that a light extraction efficiency lower than the light extraction efficiency can be obtained.
Similarly, for a / R = 0.2 system, when A / φ exceeds 0.8, a light extraction efficiency lower than the light extraction efficiency in the state where the hemispherical lens 2 is not provided is obtained. It is speculated that it is possible.
Therefore, in the organic light emitting display having a primary microcavity structure, it is preferable that a / R is 0.3 or more.

(Example 2 and Comparative Example 2: When having a secondary microcavity structure)
In Example 1, the organic organic light emitting display in the second example was used in the same manner as in Example 1 except that a secondary organic light emitting display was used instead of the organic light emitting display having the primary microcavity structure. An electroluminescent display device was constructed.
With respect to the organic light emitting display device in Example 2, the light emitted from the light emitting unit emits the light source having the light orientation distribution of m = 1 shown in FIG. The light extraction efficiency was calculated in the same manner as in Example 1 except that the calculation method in the case of having a secondary microcavity structure was used instead of the light source having a photo-alignment distribution of = 2.

In Example 2, the organic electroluminescent display device in Comparative Example 2 was configured in the same manner as Example 2 except that no light scattering layer was provided.
With respect to the organic light emitting display device of Comparative Example 2, the light emitted from the light emitting unit emits the light source having the light orientation distribution of m = 1 shown in FIG. 2 from the light emitting unit. The light extraction efficiency was calculated in the same manner as in Comparative Example 1 except that the calculation method in the case of having a secondary microcavity structure was used instead of the light source having the photo-alignment distribution of = 2.

The experimental result of the light extraction efficiency in each organic electroluminescent display device in Example 2 and Comparative Example 2 is shown in FIG. 6b. FIG. 6B is a graph showing a transition of light extraction efficiency in an organic light emitting display having a secondary microcavity structure.
As shown in FIG. 6b, in all ten systems of a / R = 0.1 to a / R = 1 of the organic light emitting display device in Example 2, the organic light emitting display device in Comparative Example 2 is used. The light extraction efficiency is higher than that of the system (m = 2 lens only), and it is assumed that a high light extraction efficiency can be obtained.
Further, in all ten systems of a / R = 0.1 to a / R = 1 of the organic electroluminescence display device in Example 2, A / φ is greater than 0 and less than or equal to 1, and the hemisphere The light extraction efficiency is lower than the light extraction efficiency in the state where no lens is arranged, and it is assumed that a high light extraction efficiency can be obtained.

(Example 3 and Comparative Example 3: When having a tertiary microcavity structure)
In Example 1, in place of the organic electroluminescent display part having the primary microcavity structure, the organic organic light emitting display part in the third example was used in the same manner as in Example 1 except that a tertiary organic electroluminescent display part was used. An electroluminescent display device was constructed.
With respect to the organic light emitting display device in Example 3, the light emitted from the light emitting unit emitted from the light emitting unit is emitted from the light source having the light orientation distribution of m = 1 shown in FIG. The light extraction efficiency was calculated in the same manner as in Example 1 except that the calculation method in the case of having a third-order microcavity structure was used instead of the light source having the photo-alignment distribution of = 3.

In Example 3, an organic electroluminescence display device in Comparative Example 3 was configured in the same manner as Example 3 except that no light scattering layer was provided.
With respect to the organic light emitting display device of Comparative Example 3, the light emitted from the light emitting unit emits light from the light emitting unit having the light orientation distribution of m = 1 shown in FIG. The light extraction efficiency was calculated in the same manner as in Comparative Example 1 except that the calculation method in the case of having a third-order microcavity structure was used instead of the light source having the optical orientation distribution of = 3.

The experimental result of the light extraction efficiency in each organic electroluminescence display device in Example 3 and Comparative Example 3 is shown in FIG. FIG. 6c is a graph showing transition of light extraction efficiency in an organic light emitting display device having a tertiary microcavity structure.
As shown in FIG. 6c, the organic electroluminescent display device of Comparative Example 3 is used in all 10 systems of a / R = 0.1 to a / R = 1 of the organic electroluminescent display device of Example 3. The light extraction efficiency is higher than that of the system (m = 3 lens only), and it is assumed that a high light extraction efficiency can be obtained.
Further, in all ten systems of a / R = 0.1 to a / R = 1 of the organic electroluminescence display device in Example 3, the hemisphere is in the whole numerical range where A / φ exceeds 0 and is 1 or less. The light extraction efficiency is lower than the light extraction efficiency in the state where no lens is arranged, and it is assumed that a high light extraction efficiency can be obtained.

(Example 4 and Comparative Example 4: No microcavity structure (NoMC))
In Example 1, it replaced with the organic electroluminescent display part which has a primary microcavity structure, It replaced with the organic electroluminescent display part which does not have a microcavity structure (NoMC), and was carried out similarly to Example 1 except having used. The organic light emitting display device in Example 4 was constructed.
With respect to the organic light emitting display device in Example 4, the light emitted from the light emitting portion emitted from the light emitting portion from the light emitting portion having the light orientation distribution of m = 1 shown in FIG. 2 is NoMc shown in FIG. The light extraction efficiency was calculated in the same manner as in Example 1 except that the calculation method in the case of having no microcavity structure (NoMC) was used instead of the light source having the photo-alignment distribution.

In Example 4, the organic electroluminescent display device in Comparative Example 4 was configured in the same manner as in Example 4 except that no light scattering layer was provided.
With respect to the organic light emitting display device of Comparative Example 4, the light emitted from the light emitting part emitted from the light source having the light orientation distribution of m = 1 shown in FIG. 2 is the NoMc shown in FIG. The light extraction efficiency was calculated in the same manner as in Comparative Example 1 except that the calculation method in the case of having no microcavity structure (NoMC) was used instead of the light source having the photo-alignment distribution.

The experimental result of the light extraction efficiency in each organic electroluminescence display device in Example 4 and Comparative Example 4 is shown in FIG. 6d. FIG. 6d is a graph showing the transition of light extraction efficiency in an organic light emitting display without a microcavity structure.
As shown in FIG. 6d, in all ten systems of a / R = 0.1 to a / R = 1 of the organic light emitting display in Example 4, the organic light emitting display in Comparative Example 4 The light extraction efficiency is higher than that of the system (NoMC lens only), and it is assumed that high light extraction efficiency can be obtained.
Further, in all ten systems of a / R = 0.1 to a / R = 1 of the organic electroluminescence display device in Example 4, A / φ is greater than 0 and less than or equal to 1, and the hemisphere The light extraction efficiency is lower than the light extraction efficiency in the state where no lens is arranged, and it is assumed that a high light extraction efficiency can be obtained.

Furthermore, with respect to each of the organic light emitting display devices in Examples 1 to 4 and Comparative Examples 1 to 4, the light extraction efficiency when focusing on the system of a / R = 0.4 will be described with reference to FIG. FIG. 6e is a diagram showing the transition of the light extraction efficiency when focusing on the system of a / R = 0.4.
In the figure shown as FIG. 6e, when A / φ is changed by 0.1 in a numerical range exceeding 0 and not exceeding 1, each organic light emitting display device has neither a hemispherical lens nor a light scattering layer. The figure shows changes in light extraction efficiency when there is a hemispherical lens and no light scattering layer, and when both a hemispherical lens and a light scattering layer are present.

As shown in FIG. 6e, the organic light emitting display devices in Examples 1 to 4 show higher light extraction efficiency than the organic light emitting display devices in Comparative Examples 1 to 4, and high light extraction efficiency is obtained. It is speculated that it is possible. Further, in the organic electroluminescence display devices in Examples 1 to 4, the A / φ is greater than 0 and less than or equal to 1, and the organic electroluminescence device is in a state where no hemispherical lens and no light scattering layer are arranged. It is assumed that high light extraction efficiency can be obtained.
On the other hand, in the organic electroluminescence display devices in Comparative Examples 1 to 4, since the A / φ exceeds 0.5, the decrease in light extraction efficiency is large, and the system in Comparative Example 4 having no microcavity structure (NoMC lens). only) shows a result in which the light extraction efficiency is inferior to that of the organic electroluminescent device in a state where the hemispherical lens and the light scattering layer are not provided, and it is assumed that sufficient light extraction efficiency cannot be obtained.

<Evaluation of front brightness>
Front brightness is an important performance parameter for organic electroluminescent display devices. From the viewpoint of obtaining a high light extraction efficiency while maintaining the front luminance, conditions for obtaining a preferable front luminance in the organic light emitting display devices of Examples 1 to 4 are studied.

(Example 1 and Comparative Example 1: having a primary microcavity structure)
In Example 1, ten systems of a / R = 0.1 to a / R = 1 in which the numerical value is changed by 0.1 within a numerical range of 0.1 to 1 are used. . In the first embodiment, when A / φ is changed by 0.1 in a numerical range of 0.3 to 1, in any of 10 systems with front luminance of 1 to a / R = 1. It was calculated how it changed.
The front luminance in the organic light emitting display device in Example 1 was calculated as follows.
In order to confirm the effect of the scattering layer, using the ray tracing optical system design software, the hemispherical lens refractive index n = 1.8 and the diameter φ2 mm for the model of FIG. It is assumed that the light scattering layer 23 is arranged on the light incident surface of the hemispherical lens at 0.2 mm, the refractive index n = 1.8 of the light emitting portion, and the light scattering in the light scattering layer 23 is Lambertian scattering. And perform a simulation. The organic light emitting display device has a cavity order m = 1 structure having a microcavity, and the light emitted from the light emitting unit is a light source having a photo-alignment distribution of m = 1 shown in FIG. 2, and as shown in FIG. 3b. The maximum side length A of the rectangular light emitting surface is changed by 0.2 mm in a range of 0 to 2 mm. The scattering diameter a as shown in FIG. 5b changes the proportionality factor with respect to the radius of the hemispherical lens, and the light emitted from the light-emitting portion depends on the radiation power (W) and radiation angle of the light emitted to the air through the scattering layer and the hemispherical lens Considering the radiant intensity (W / St.), The ratio of the power of the radiated light to the air and the power of the light emitted from the light emitting part is the light extraction efficiency, and the radiant intensity at the radiation angle of 0 degree is the front luminance. .

In Comparative Example 1, how the front luminance in the system of Comparative Example 1 (m = 1 lens only) is changed when A / φ is changed by 0.1 in the numerical range of 0.3 to 1. Calculated whether to change.
The front luminance in the organic light emitting display device in Comparative Example 1 was calculated as follows.
In order to confirm the effect of the scattering layer, using the ray tracing optical system design software, the hemispherical lens refractive index n = 1.8 and the diameter φ2 mm for the model of FIG. The simulation is performed on the assumption that the refractive index n of the light emitting part is 1.8 mm at 0.2 mm. The organic light emitting display device has a cavity order m = 1 structure having a microcavity, and the light emitted from the light emitting unit is a light source having a photo-alignment distribution of m = 1 shown in FIG. 2, and as shown in FIG. 3b. The maximum side length A of the rectangular light emitting surface is changed by 0.2 mm in the range of 0 to 2 mm, and the light emitted from the light emitting part is emitted to the air through the scattering layer and the hemispherical lens (W) and the radiation angle. Considering the dependent radiant intensity (W / St.), The ratio of the power of the radiated light to the air and the power of the light emitted from the light emitting part is the light extraction efficiency, and the radiant intensity at the radiation angle of 0 degrees is the front luminance. To do.

FIG. 7a-1 shows the experimental results of the front luminance in the organic light emitting display devices in Example 1 and Comparative Example 1. FIG. 7 a-1 is a diagram showing a transition of front luminance in an organic light emitting display having a primary microcavity structure.
As shown in FIG. 7a-1, when A / φ exceeds 0.5, in some of the systems with a / R = 0.1-1, hemispherical lenses and scattering layers are arranged. It is confirmed that the front luminance is inferior to that in the state of not performing.
Therefore, in an organic light emitting display device having a primary microcavity structure, in order to obtain high light extraction efficiency while maintaining front luminance, a / R is expressed by the following equation: 0.3 ≦ a / R ≦ It is preferable to satisfy the relationship of 0.5.

7a-2, among the systems of the organic electroluminescent display device in Example 1, the system of a / R = 0.3 to 0.5 and the system of the organic electroluminescent display device in Comparative Example 1 (m = 1). (lens only) shows the transition of the front luminance. FIG. 7a-2 is a diagram showing the transition of the front luminance of the system with a / R = 0.3 to 0.5 and the system with m = 1 lens only in FIG. 7a-1.
As shown in FIG. 7 a-2, among the systems of the organic light emitting display device in Example 1, in the system of a / R = 0.3 to 0.5, the organic light emitting display device in Comparative Example 1 The front luminance equivalent to that of the system (m = 1 lens only) is shown, and it is presumed that high light extraction efficiency can be obtained while maintaining the front luminance.
Further, in the system of the organic electroluminescence display device in Example 1, in the system of a / R = 0.3 to 0.5, the hemispherical lens is in the whole numerical range where A / φ is 0.3 to 1. In addition, the front luminance is substantially equal to or higher than the state in which the light scattering layer is not provided, and it is presumed that high light extraction efficiency can be obtained while maintaining the front luminance. In particular, when A / φ satisfies the relationship of the following formula, 0.3 ≦ A / φ ≦ 0.7, it is shown that a higher front luminance can be obtained than when no hemispherical lens and a scattering layer are arranged, It is presumed that excellent characteristics can be obtained both in the front luminance and the light extraction efficiency.

Further, in the organic light emitting display devices in Example 1 and Comparative Example 1, as an example, a change in front luminance focusing on the system of a / R = 0.4 will be described with reference to FIG. FIG. 8A is a diagram showing a transition of front luminance when focusing on the system of a / R = 0.4 in Example 1 and Comparative Example 1. FIG.
As shown in FIG. 8a, in the organic electroluminescent display device (lens & scatter) in Example 1, the front luminance not inferior to the organic electroluminescent display device (lens only) in Comparative Example 1 is obtained, and A / φ is further obtained. If it exceeds 0.8, it is presumed that a higher front luminance than that of the organic electroluminescence display device in Comparative Example 1 can be obtained.

(Example 2 and Comparative Example 2: When having a secondary microcavity structure)
For the organic light emitting display device of Example 2, the light emitted from the light emitting part emitted from the light emitting part emitted from the light emitting part has the light orientation distribution of m = 1 shown in FIG. The front luminance was calculated in the same manner as in Example 1 except that the calculation method in the case of having a secondary microcavity structure was used instead of the light source having a photo-alignment distribution of 2.
With respect to the organic light emitting display device in Comparative Example 2, the light emitted from the light emitting unit emits the light source having the light orientation distribution of m = 1 shown in FIG. The front luminance was calculated in the same manner as in Comparative Example 1 except that the calculation method in the case of having a secondary microcavity structure was used instead of the light source having the photo-alignment distribution of 2.

An experimental result of the front luminance in the organic light emitting display devices in Example 2 and Comparative Example 2 is shown in FIG. FIG. 7 b-1 is a diagram showing a transition of front luminance in an organic light emitting display having a secondary microcavity structure.
As shown in FIG. 7b-1, when A / φ exceeds 0.6, in some of the systems with a / R = 0.1-1, hemispherical lenses and scattering layers are arranged. It is confirmed that the front luminance is inferior to that in the state of not performing.
Therefore, in an organic light emitting display having a secondary microcavity structure, in order to obtain high light extraction efficiency while maintaining front luminance, a / R is expressed by the following equation: 0.3 ≦ a / R ≦ It is preferable to satisfy the relationship of 0.6.

7b-2, among the systems of the organic electroluminescent display device in Example 2, the system of a / R = 0.3 to 0.6 and the system of the organic electroluminescent display device in Comparative Example 2 (m = 2). (lens only) shows the transition of the front luminance. FIG. 7 b-2 is a diagram showing the transition of the front luminance of the system with a / R = 0.3 to 0.6 and the system with m = 2 lens only in FIG. 7 b-1.
As shown in FIG. 7 b-2, among the systems of the organic light emitting display device in Example 2, in the system of a / R = 0.3 to 0.6, the organic light emitting display device in Comparative Example 2 A front luminance equivalent to or higher than that of the system (m = 2 lens only) is shown, and it is presumed that high light extraction efficiency can be obtained while maintaining the front luminance.
Further, in the system of the organic electroluminescence display device in Example 2, in the system of a / R = 0.3 to 0.6, the hemispherical lens is in the whole numerical range where A / φ is 0.3 to 1. In addition, the front luminance is substantially equal to or higher than the state in which the light scattering layer is not provided, and it is presumed that high light extraction efficiency can be obtained while maintaining the front luminance. In particular, when A / φ satisfies the relationship of the following formula, 0.3 ≦ A / φ ≦ 0.7, it is shown that a higher front luminance can be obtained than when no hemispherical lens and a scattering layer are arranged, It is presumed that excellent characteristics can be obtained both in the front luminance and the light extraction efficiency.

In addition, in the organic light emitting display devices in Example 2 and Comparative Example 2, as an example, a change in front luminance focusing on the system of a / R = 0.4 will be described with reference to FIG. FIG. 8B is a diagram illustrating the transition of the front luminance when focusing on the system of a / R = 0.4 in Example 2 and Comparative Example 2.
As shown in FIG. 8b, in the organic electroluminescent display device (lens & scatter) in Example 2, the front luminance not inferior to that of the organic electroluminescent display device (lens only) in Comparative Example 2 is obtained, and A / φ is further obtained. If it exceeds 0.6, it is presumed that a higher front luminance than that of the organic light emitting display in Comparative Example 2 can be obtained.

(Example 3 and Comparative Example 3: When having a tertiary microcavity structure)
For the organic light emitting display device of Example 3, the light emitted from the light emitting unit emits the light source having the light orientation distribution of m = 1 shown in FIG. The front luminance was calculated in the same manner as in Example 1 except that the calculation method in the case of having a tertiary microcavity structure was used instead of the light source having a photo-alignment distribution of 3.
With respect to the organic light emitting display device in Comparative Example 3, the light emitted from the light emitting unit emits the light source having the light orientation distribution of m = 1 shown in FIG. The front luminance was calculated in the same manner as in Comparative Example 1 except that the calculation method in the case of having a third-order microcavity structure was used instead of the light source having a photo-alignment distribution of 3.

The experimental result of the front luminance in the organic light emitting display devices in Example 3 and Comparative Example 3 is shown in FIG. FIG. 7 c-1 is a diagram showing a transition of front luminance in an organic light emitting display device having a tertiary microcavity structure.
As shown in FIG. 7c-1, when A / φ exceeds 0.7, in some of the systems with a / R = 0.1-1, hemispherical lenses and scattering layers are arranged. It is confirmed that the front luminance is inferior to that in the state of not performing.
Therefore, in an organic light emitting display having a tertiary microcavity structure, in order to obtain high light extraction efficiency while maintaining front luminance, a / R is expressed by the following formula: 0.4 ≦ a / R ≦ It is preferable to satisfy the relationship of 0.7.

FIG. 7 c-2 shows a system of a / R = 0.4 to 0.7 among the systems of the organic light emitting display device in Example 3, and the system of the organic light emitting display device in Comparative Example 3 (m = 3 (lens only) shows the transition of the front luminance. FIG. 7c-2 is a diagram showing the transition of the front luminance of the system with a / R = 0.4 to 0.7 and the system with m = 3 lens only in FIG. 7c-1.
As shown in FIG. 7 c-2, among the systems of the organic light emitting display device in Example 3, in the system of a / R = 0.4 to 0.7, the organic light emitting display device in Comparative Example 3 A front luminance equivalent to or higher than that of the system (m = 3 lens only) is shown, and it is presumed that high light extraction efficiency can be obtained while maintaining the front luminance.
Moreover, in the system of the organic electroluminescence display device in Example 3, in the system of a / R = 0.4 to 0.7, the hemispherical lens in the whole numerical range where A / φ is 0.3 to 1. In addition, the front luminance is substantially equal to or higher than the state in which the light scattering layer is not provided, and it is presumed that high light extraction efficiency can be obtained while maintaining the front luminance. In particular, when A / φ satisfies the relationship of the following formula, 0.3 ≦ A / φ ≦ 0.7, it is shown that a higher front luminance can be obtained than when no hemispherical lens and a scattering layer are arranged, It is presumed that excellent characteristics can be obtained both in the front luminance and the light extraction efficiency.

Further, in the organic light emitting display devices according to Example 3 and Comparative Example 3, as an example, a change in front luminance focusing on the system of a / R = 0.4 will be described with reference to FIG. FIG. 8c is a diagram showing the transition of the front luminance when focusing on the system of a / R = 0.4 in Example 3 and Comparative Example 3.
As shown in FIG. 8c, in the organic electroluminescent display device (lens & scatter) in Example 3, the front luminance not inferior to the organic electroluminescent display device (lens only) in Comparative Example 3 is obtained, and A / φ is further obtained. If it exceeds 0.6, it is presumed that a higher front luminance than that of the organic electroluminescence display device in Comparative Example 3 can be obtained.

(Example 4 and Comparative Example 4: When not having a microcavity structure)
In contrast to the organic light emitting display device of Example 4, the light emitted from the light emitting unit emits light from the light emitting unit having the light orientation distribution of m = 1 shown in FIG. The front luminance was calculated in the same manner as in Example 1 except that the calculation method in the case of not having the microcavity structure was used instead of the light source having the photo-alignment distribution.
For the organic light emitting display device in Comparative Example 4, the light emitted from the light emitting part emits the light source having the light orientation distribution of m = 1 shown in FIG. 2 from the light emitting part. The front luminance was calculated in the same manner as in Comparative Example 1 except that the calculation method in the case of not having the microcavity structure was used instead of the light source having the photo-alignment distribution.

An experimental result of the front luminance in the organic light emitting display devices in Example 4 and Comparative Example 4 is shown in FIG. FIG. 7 d-1 is a diagram showing a transition of front luminance in an organic light emitting display device that does not have a microcavity structure.
As shown in FIG. 7d-1, a front luminance of approximately equal to or higher than that in a state where A / φ is 0.3 to 1 and no hemispherical lens and a scattering layer are arranged is obtained. Is confirmed.
In an organic light emitting display having a tertiary microcavity structure, in order to obtain high light extraction efficiency while maintaining front luminance, a / R satisfies the following formula: 0.4 ≦ a / R ≦ 1 It is preferable to satisfy the relationship.

7d-2, among the systems of the organic light emitting display device in Example 4, the system of a / R = 0.4 to 1 and the system of the organic light emitting display device in Comparative Example 4 (NoMC lens only). The transition of front luminance is shown. FIG. 7d-2 is a diagram showing the transition of the front luminance of the system with a / R = 0.4 to 1 and the system with m = NoMC lens only in FIG. 7d-1.
As shown in FIG. 7d-2, among the systems of the organic light emitting display device in Example 4, in the system of a / R = 0.4 to 1, the system of the organic light emitting display device in Comparative Example 4 ( The front luminance is higher than that of NoMC lens only), and it is presumed that excellent performance can be obtained in both front luminance and light extraction efficiency.
Further, in the system of the organic electroluminescence display device in Example 4, in the system of a / R = 0.4 to 1, the hemispherical lens and the light are in the whole numerical range where A / φ is 0.3 to 1. A higher front luminance than in the case where no scattering layer is provided is shown, and it is presumed that excellent performance is obtained in both front luminance and light extraction efficiency.

In addition, in the organic light emitting display devices in Example 4 and Comparative Example 4, as an example, a change in front luminance focusing on the system of a / R = 0.4 will be described with reference to FIG. FIG. 8d is a diagram showing the transition of the front luminance when focusing on the system of a / R = 0.4 in Example 4 and Comparative Example 4.
As shown in FIG. 8d, in the organic electroluminescent display device (lens & scatter) in Example 4, the organic electroluminescent display device (lens only) in Comparative Example 4 is in the whole range from a / R = 0.3 to 1. It is assumed that a higher front luminance is obtained.

(Production Example 1-1: bottom emission type organic electroluminescence display part)
The following four types of organic electroluminescence display parts (1) to (4) having a bottom emission type structure were produced as follows.

<Preparation of organic electroluminescence display part (1): When having a secondary microcavity structure>
As a glass substrate, S-TIH6 (made by OHARA) having a thickness d of 0.2 mm and a refractive index of 1.8 was used.
Next, Ag was vacuum-deposited on the glass substrate so as to have a thickness of 20 nm.
Next, vacuum is applied to the anode at a ratio of 2-TNATA [4,4 ′, 4 ″ -tris (2-naphthylphenylamino) triphenylamine] and MnO ₃ and 7: 3 to a thickness of 20 nm. Evaporation was performed to form a hole injection layer.
Next, on the hole injection layer, 2-TNATA is doped with F4-TCNQ (2,3,5,6-tetrafluoro-7,7,8,8 tetracyanoquinodimethane) 1.0% so as to have a thickness of 141 nm. Vacuum deposition was performed to form a first hole transport layer.
Next, α-NPD [N, N ′-(dinaphthylphenylamino) pyrene] is vacuum-deposited on the first hole transport layer so as to have a thickness of 10 nm to form a second hole transport layer. did.
Next, a hole transport material A represented by the following structural formula was vacuum deposited on the second hole transport layer so as to have a thickness of 3 nm to form a third hole transport layer.

Next, on the third hole transport layer, CBP (4,4′-dicarbazole-biphenyl) as a host material and a light emitting material A represented by the following structural formula as a light emitting material in a ratio of 85:15 Then, the light-emitting layer was formed by co-evaporation so that the thickness was 20 nm.

Next, BAlq (Aluminum (III) bis (2-methyl-8-quinolinato) -4-phenylphenolate) is vacuum-deposited on the light emitting layer so as to have a thickness of 39 nm to form a first electron transport layer. did.
Next, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenthrolin) is vacuum-deposited on the first electron transport layer so as to have a thickness of 1 nm, and the second electron transport is performed. A layer was formed.
Next, LiF was vacuum-deposited on the second electron transport layer so as to have a thickness of 1 nm to form a first electron injection layer.
Next, Al was vacuum-deposited on the first electron injection layer so as to have a thickness of 1 nm to form a second electron injection layer.
Next, Al was vacuum-deposited on the second electron injection layer so as to have a thickness of 100 nm to form a cathode.
The organic electroluminescence display part (1) was produced by the above. The obtained organic electroluminescent display part (1) had a secondary microcavity structure with an optical length L (λ) of 2λ (where λ represents an emission wavelength).

<Preparation of organic electroluminescence display part (2): When having a tertiary microcavity structure>
In the organic electroluminescence display section (1), the organic electroluminescence display section (2) is the same as the organic electroluminescence display section (1) except that the thickness of the first hole transport layer is changed from 141 nm to 271 nm. Was made.
The obtained organic electroluminescence display part (2) had a tertiary microcavity structure with an optical length L (λ) of 3λ (where λ represents a light emission wavelength).

<Preparation of organic electroluminescence display part (3); when it does not have a microcavity structure>
In the organic electroluminescence display section (1), the anode is formed in the same manner as the organic electroluminescence display section (1) except that ITO is vacuum-deposited to a thickness of 100 nm instead of vacuum-depositing Ag to a thickness of 20 nm. Thus, an organic electroluminescence display part (3) was produced.
The obtained organic EL element (3) was a structure having no microcavity structure.

<Preparation of organic electroluminescence display part (4); in case of primary microcavity structure>
In the organic electroluminescence display section (1), the organic electroluminescence display section (4) is the same as the organic electroluminescence display section (1) except that the thickness of the first hole transport layer is changed from 141 nm to 11 nm. Was made.
The obtained organic electroluminescent display section (4) had a primary microcavity structure with an optical length L (λ) of 1λ (where λ represents a light emission wavelength).

(Comparative Examples 5 to 8)
Thus, the produced bottom emission type organic electroluminescence display portions (1) to (4) are optimized for green (about 530 nm) emission.
Next, a cylinder lens having a sufficiently large diameter (radius 10 mm) and a refractive index of 1.8 on each of the organic electroluminescent display portions (1) to (4) on a glass substrate as a light extraction surface thereof. Were attached with matching oil (refractive index = 1.8), and organic electroluminescence display devices in Comparative Examples 5 to 8 were produced.
In addition, the organic electroluminescent display apparatus in the comparative example 5 is an organic electroluminescent display apparatus (m = 2) which has a secondary microcavity structure which has an organic electroluminescent display part (1). The organic electroluminescent display device in Comparative Example 6 is an organic electroluminescent display device (m = 2) having a tertiary microcavity structure having an organic electroluminescent display portion (2). The organic electroluminescent display device in Comparative Example 7 is an organic electroluminescent display device (NoMC) not having a microcavity structure having an organic electroluminescent display portion (3). The organic electroluminescent display device in Comparative Example 8 is an organic electroluminescent display device having a primary microcavity structure having an organic electroluminescent display portion (4).

The outline | summary of the organic electroluminescent display apparatus in Comparative Examples 5-8 manufactured is demonstrated using FIG. 9a and FIG. 9b. FIG. 9A is an explanatory view showing an outline of an organic light emitting display device according to a comparative example, and FIG. 9B is a view for explaining extraction of light in FIG. 9A.
The maximum side length A of the light emitting unit (pixel) 21 is 2 mm. Further, in order to prevent light emitted from the light emitting unit (pixel) 21 from being emitted to the lens of the adjacent pixel, the distance d between the light emitting unit (pixel) 21 and the lens 22 is defined as d and the diameter φ of the lens. The ratio d / φ was not exceeded 1/10.
In the organic light emitting display configured as described above, light emitted from the light emitting unit (pixel) 21 is extracted from the lens 22 disposed on the bottom of the glass substrate.

  About the organic electroluminescent display apparatus in Comparative Examples 5-8, light distribution was measured as follows. Based on the measurement result, the angular distribution of light in the glass can be known. The results are shown in FIG.

<Measurement method of light distribution>
A silicon detector is attached to the goniometer, each organic EL element is caused to emit light, the relationship between the angle of the goniometer and the voltage signal corresponding to the light intensity from the detector is measured, and the light distribution is obtained.

  From the results of FIG. 2, it can be seen that the light distribution (the angular distribution of light) within the glass in the organic light emitting display devices in Comparative Examples 5 to 8 varies greatly depending on the structure of the organic light emitting display device.

  Here, when the lens as the light extraction member is not attached to the light extraction surface of the organic light emitting display device in Comparative Examples 5 to 8, the total reflection angle of the glass-air interface is ± 33 °, No light is emitted into the air at angles greater than this angle (see FIG. 3a).

Next, in the organic electroluminescent display devices in Comparative Examples 5 to 8, a case where a lens as a light extraction member is mounted will be considered.
As shown in FIG. 9a, when the light emitting layer (light emitting layer) 21 is close to the center of the lens 22, most of the light is emitted into the air. On the other hand, as shown in FIG. 9b, when the light emitting layer (light emitting layer) 21 deviates from the center of the lens 22, most of the light is not radiated into the air and repeats total reflection in the lens.
Therefore, as the amount of light directed to the front in the glass increases, the amount of total reflected light when the lens deviates from the center of the lens increases, so that the light extraction efficiency tends to decrease.

If the ratio (A / φ) between the lens diameter φ and the maximum length A of one side of the pixel is sufficiently small, most of the light is emitted, but the ratio (A / φ) approaches 1. It is predicted that the emitted light will decrease.
In order to solve this problem, a light scattering layer is disposed between the light emitting layer and the hemispherical lens.

(Examples 5 to 8)
For each of the produced organic electroluminescence display parts (1) to (4), 16% by mass of TiO ₂ fine particles were dispersed in a transparent resist on a glass substrate at a position corresponding to the light emitting layer (pixel). After applying the dispersion and forming a film, exposure and development were performed to form a light scattering layer having an opening of 1 mm × 1 mm in the center.
Here, the dispersion is composed of propylene glycol monomethyl ether acetate (PGMA, manufactured by Wako Co., Ltd.) and DPHA (n = 1.54, manufactured by Nippon Kayaku Co., Ltd.) in a mass ratio of 17: 3 (PGMA: DPHA). A mixed DPHA solution was prepared, and 0.05 parts by mass of titanium oxide (n = 2.6, manufactured by Ishihara Sangyo) having a mass average particle diameter of 300 nm was added to 1 part by mass of the DPHA solution, followed by ultrasonic dispersion. Prepared.
The dispersion was formed by depositing a magnesium fluoride film (n = 1.37) on a glass substrate and then applying the dispersion by spin coating at 200 ° C. It was done by drying. The dry film thickness of the dispersion was 800 nm.
After forming the light scattering layer as described above, a hemispherical lens is formed by an imprint process so that the opening center of the light scattering layer matches the center axis of the lens, and the organic electroluminescence display units (1) to (4) The organic electric field light display apparatus in Examples 5-8 which arranged the light-scattering layer and the hemispherical lens with respect to each of these was manufactured.
In addition, the organic electroluminescent display apparatus in Example 5 is an organic electroluminescent display apparatus (m = 2) which has a secondary microcavity structure which has an organic electroluminescent display part (1). The organic electroluminescent display device in Example 6 is an organic electroluminescent display device (m = 2) having a tertiary microcavity structure having an organic electroluminescent display portion (2). The organic electroluminescent display device in Example 7 is an organic electroluminescent display device (NoMC) having no microcavity structure having an organic electroluminescent display portion (3). The organic electroluminescent display device in Example 8 is an organic electroluminescent display device having a primary microcavity structure having an organic electroluminescent display portion (4).

An outline of the bottom emission type organic light emitting display in Examples 5 to 8 is shown in FIGS. 9c and 9d. FIG. 9c is an explanatory diagram for explaining the outline of the organic light emitting display device according to the bottom emission type embodiment, and FIG. 9d is an explanatory diagram when FIG. 9a is viewed from the plane.
As shown in FIG. 9 a, a light scattering layer 23 is disposed at a position corresponding to the light emitting unit (pixel) 21 having a maximum side length A, and a hemispherical lens 22 is disposed on the light scattering layer 23. . In the example of FIG. 9c, the light scattering layer 21 is formed as an annular layer having an opening in a circular region centered on the central axis of the hemispherical lens 22 (see FIG. 9d).

(Production Example 1-2: bottom emission type organic electroluminescence display device)
In Examples 5-8, the manufacture example of the organic electroluminescent display apparatus which forms a light-scattering layer and a hemispherical lens in this order on the glass substrate as a light extraction surface was demonstrated, but such a manufacture example Instead of the above structure, the light scattering layer may be arranged between the glass substrate as the light extraction surface and the light emitting layer. Based on such a configuration, organic light emitting display devices in Examples 9 to 12 below were manufactured.

Example 9
In Example 5, instead of forming the anode on the glass substrate of the organic electroluminescence display part (1), a light scattering layer was formed by the same method as in Example 5, and the anode was formed on the light scattering layer. Except that the hemispherical lens was directly formed on the surface opposite to the surface on which the light scattering layer of the organic electroluminescence display portion (1) was formed, The organic electroluminescent display device in Example 9 was manufactured.

(Example 10)
In Example 6, instead of forming the anode on the glass substrate of the organic electroluminescence display part (2), a light scattering layer was formed by the same method as in Example 6, and the anode was formed on the light scattering layer. Except that the hemispherical lens was directly formed on the surface opposite to the surface on which the light scattering layer of the organic electroluminescent display portion (2) was formed, as in Example 6, An organic light emitting display device in Example 10 was manufactured.

(Example 11)
In Example 7, instead of forming the anode on the glass substrate of the organic electroluminescence display part (3), a light scattering layer was formed by the same method as in Example 7, and the anode was formed on the light scattering layer. Except that the hemispherical lens was directly formed on the surface opposite to the surface on which the light scattering layer of the organic electroluminescent display portion (3) was formed, as in Example 7, An organic light emitting display device in Example 11 was manufactured.

(Example 12)
In Example 8, instead of forming the anode on the glass substrate of the organic electroluminescence display part (4), a light scattering layer was formed by the same method as in Example 8, and the anode was formed on the light scattering layer. Except that the hemispherical lens was directly formed on the surface opposite to the surface on which the light scattering layer of the organic electroluminescent display portion (4) was formed, in the same manner as in Example 8, An organic light emitting display device in Example 12 was manufactured.

Further, in Examples 5 to 8, examples of forming a light scattering layer using a dispersion in which 16% by mass of TiO ₂ fine particles are dispersed in a transparent resist are described. The scattering layer may be formed by an uneven layer. Based on such a configuration, organic electroluminescence display devices in Examples 13 to 16 below were manufactured.

(Example 13)
Instead of the method for forming the light scattering layer in Example 5, the organic electroluminescence display device in Example 13 was manufactured in the same manner as in Example 5 except that the light scattering layer was formed by the following forming method. .
That is, a Cr metal pattern was formed on a glass substrate having a refractive index of about 1.5 by dry etching using lithography and a chlorine-based gas (either BCl ₃ , Cl ₂ , SiCl ₄ , HCl, or a mixed gas thereof). Thereafter, dry etching is further performed using a fluorine-based gas (HF, SiF ₄ , SF ₄ , or a mixed gas thereof) to have a convex portion having a period of 1.8 μm, a width of 1.4 μm, and a height of 1.2 μm. A light scattering layer consisting of irregularities was formed. Next, a light having a high refractive index material (SiON, manufactured by High Purity Chemical Co., Inc., refractive index: 1.7 to 1.9) formed thereon with a thickness of about 2 μm by the CVD method, and the unevenness is flattened. A scattering layer was formed. The back surface of the glass substrate opposite to the surface on which the light scattering layer was formed was polished to form various layers including an anode, and a hemispherical lens was formed on the light scattering layer.

(Example 14)
The organic electroluminescence in Example 14 is the same as Example 6 except that the light scattering layer is formed by the light scattering layer forming method in Example 13 instead of the light scattering layer forming method in Example 6. A display device was manufactured.

(Example 15)
Organic electroluminescence in Example 15 is the same as Example 7 except that the light scattering layer is formed by the light scattering layer forming method in Example 13 instead of the light scattering layer forming method in Example 7. A display device was manufactured.

(Example 16)
Organic electroluminescence in Example 16 is the same as Example 8 except that the light scattering layer is formed by the light scattering layer forming method in Example 13 instead of the light scattering layer forming method in Example 8. A display device was manufactured.

(Production Example 2: Top emission type organic electroluminescence display device)
The following four types of organic electroluminescence display parts (5) to (7) having a top emission type structure were produced as follows.

<Preparation of organic electroluminescence display part (5); Case of having secondary microcavity structure>
As a glass substrate, Eagle 2000 (manufactured by Corning) having a thickness of 0.7 mm and a refractive index of 1.5 was used.
Next, Al was vacuum-deposited on the glass substrate so as to have a thickness of 100 nm to form an anode.
Next, vacuum is applied on the anode such that 2-TNATA [4,4 ′, 4 ″ -tris (2-naphthylphenylamino) triphenylamine] and MnO ₃ are in a ratio of 7: 3 to a thickness of 20 nm. Evaporation was performed to form a hole injection layer.
Next, on the hole injection layer, 2-TNATA is doped with F4-TCNQ (2,3,5,6-tetrafluoro-7,7,8,8 tetracyanoquinodimethane) 1.0% so as to have a thickness of 141 nm. Vacuum deposition was performed to form a first hole transport layer.
Next, α-NPD [N, N ′-(dinaphthylphenylamino) pyrene] is vacuum-deposited on the first hole transport layer so as to have a thickness of 10 nm to form a second hole transport layer. did.
Next, a hole transport material A represented by the following structural formula as a third hole transport layer is vacuum-deposited on the second hole transport layer so as to have a thickness of 3 nm, and the third hole transport layer is formed. Formed.

Next, on the third hole transport layer, the light-emitting layer is formed using CBP (4,4′-dicarbazole-biphenyl) as a host material, and the light-emitting material A represented by the following structural formula as a light-emitting material, 85: It was formed by vacuum co-evaporation so that the thickness was 20 nm at a ratio of 15.

Next, BAlq (Aluminum (III) bis (2-methyl-8-quinolinato) -4-phenylphenolate) is vacuum-deposited on the light emitting layer so as to have a thickness of 39 nm to form a first electron transport layer. did.
Next, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenthrolin) is vacuum-deposited on the first electron transport layer so as to have a thickness of 1 nm, and second electron transport is performed. A layer was formed.
Next, LiF was vacuum-deposited on the second electron transport layer so as to have a thickness of 1 nm to form a first electron injection layer.
Next, Al was vacuum-deposited on the first electron injection layer so as to have a thickness of 1 nm to form a second electron injection layer.
Next, Ag was vacuum-deposited on the second electron injection layer so as to have a thickness of 20 nm to form a cathode.
Next, SiON was vapor-deposited on the cathode to form a sealing layer having a thickness of 3,000 nm, thereby forming an organic electroluminescence display part (5). The obtained organic electroluminescence display part (5) had a secondary microcavity structure with an optical length L (λ) of 2λ (where λ represents a light emission wavelength).

<Preparation of organic electroluminescence display part (6): When having a tertiary microcavity structure>
In the organic electroluminescence display part (5), the thickness of the first hole transport layer was changed from 141 nm to 271 nm, and the organic fluorine material ((C ₆ F ₁₀ O) _n ) was thickened on the sealing layer. The organic electroluminescence display part (6) was produced in the same manner as the organic electroluminescence display part (5) except that the oil-coating layer was formed by spin coating so as to be 3,000 nm.
The obtained organic electroluminescence display part (6) had a tertiary microcavity structure with an optical length L (λ) of 3λ (where λ represents a light emission wavelength).

<Preparation of organic electroluminescence display part (7); Case of primary microcavity structure>
In the organic electroluminescence display section (5), the organic electroluminescence display section (7) is the same as the organic electroluminescence display section (5) except that the thickness of the first hole transport layer is changed from 141 nm to 11 nm. Was made.
The obtained organic electroluminescence display part (7) had a primary microcavity structure with an optical length L (λ) of 1λ (where λ represents a light emission wavelength).

(Comparative Examples 9-11)
The top emission type organic electroluminescence display sections (5) to (7) thus fabricated are optimized for green (about 530 nm) emission.
Next, with respect to each of the organic electroluminescent display portions (5) to (7), a sufficiently large diameter (radius 10 mm) and a refractive index of 1.8 are formed on the sealing layer SiON as the light extraction surface. The cylinder lens was attached with matching oil (refractive index = 1.8), and organic electroluminescence display devices in Comparative Examples 9 to 12 were manufactured.
In addition, the organic electroluminescent display apparatus in the comparative example 9 is an organic electroluminescent display apparatus (m = 2) which has a secondary microcavity structure which has an organic electroluminescent display part (5). The organic electroluminescent display device in Comparative Example 10 is an organic electroluminescent display device (m = 2) having a tertiary microcavity structure having an organic electroluminescent display portion (6). The organic electroluminescent display device in Comparative Example 11 is an organic electroluminescent display device having a primary microcavity structure having an organic electroluminescent display portion (7).

The maximum side length A of the light emitting layer (pixel) in the organic light emitting display devices in Comparative Examples 9 to 11 manufactured is 2 mm. Further, the distance d between the distance d and the lens diameter φ is defined as d, so that light from the light-emitting layer (pixel) is not emitted to the lens of the adjacent pixel. / Φ did not exceed 1/10.
In the organic light emitting display configured as described above, light emitted from the light emitting layer (pixel) is extracted from a lens disposed on the sealing layer SiON.

  About the organic electroluminescent display apparatus in Comparative Examples 9-11, light distribution was measured as follows. Based on the measurement result, the angular distribution of light in the glass can be known. The results are shown in FIG. The light distribution distribution measuring method is the same as the measuring method in the bottom emission type organic electroluminescent display device.

From the results of FIG. 2, it can be seen that the light distribution (the angular distribution of light) within the glass in the organic light emitting display devices in Comparative Examples 9 to 11 varies greatly depending on the structure of the organic light emitting display device.
Here, when a lens as a light extraction member is not attached to the light extraction surface of the organic light emitting display devices in Comparative Examples 9 to 11, the total reflection angle at the glass-air interface is ± 33 °. No light is emitted into the air at angles greater than this angle (see FIG. 3a).

Next, in the organic electroluminescence display devices in Comparative Examples 9 to 11, a case where a lens as a light extraction member is mounted will be considered.
As shown in FIG. 3b, when the light emitting layer (light emitting layer) 21 is close to the center of the lens 22, most of the light is emitted into the air. On the other hand, as shown in FIG. 3c, when the light emitting layer (light emitting layer) 21 deviates from the center of the lens 22, most of the light is not radiated into the air and repeats total reflection in the lens.
Therefore, as the amount of light directed to the front in the glass increases, the amount of total reflected light when the lens deviates from the center of the lens increases, so that the light extraction efficiency tends to decrease.
If the ratio (A / φ) between the lens diameter φ and the maximum length A of one side of the pixel is sufficiently small, most of the light is emitted, but the ratio (A / φ) approaches 1. It is predicted that the emitted light will decrease.
In order to solve this problem, a light scattering layer is disposed between the light emitting layer and the hemispherical lens.

(Examples 17 to 19)
For each of the produced organic electroluminescence display parts (5) to (7), 16% by mass of TiO ₂ fine particles are dispersed in a transparent resist on the sealing film SiON at a position corresponding to the light emitting layer (pixel). The dispersion liquid was applied, formed into a film, and then exposed and developed to form a light scattering layer having an opening of 1 mm × 1 mm in the center.
Here, the dispersion is composed of propylene glycol monomethyl ether acetate (PGMA, manufactured by Wako Co., Ltd.) and DPHA (n = 1.54, manufactured by Nippon Kayaku Co., Ltd.) in a mass ratio of 17: 3 (PGMA: DPHA). A mixed DPHA solution was prepared, and 0.05 parts by mass of titanium oxide (n = 2.6, manufactured by Ishihara Sangyo) having a mass average particle diameter of 300 nm was added to 1 part by mass of the DPHA solution, followed by ultrasonic dispersion. Prepared.
The dispersion was formed by depositing a magnesium fluoride film (n = 1.37) on a glass substrate and then applying the dispersion by spin coating at 200 ° C. It was done by drying. The dry film thickness of the dispersion was 800 nm.
After forming the light scattering layer as described above, a hemispherical lens is formed by an imprint process so that the opening center of the light scattering layer matches the central axis of the lens, and the organic electroluminescence display units (5) to (7) Organic electro-wave light display devices in Examples 17 to 19 in which a light scattering layer and a hemispherical lens were arranged for each of the above were manufactured.
The organic electroluminescent display device in Example 17 is an organic electroluminescent display device (m = 2) having a secondary microcavity structure having an organic electroluminescent display portion (5). The organic electroluminescent display device in Example 18 is an organic electroluminescent display device (m = 2) having a tertiary microcavity structure having an organic electroluminescent display portion (6). The organic electroluminescent display device in Example 19 is an organic electroluminescent display device having a primary microcavity structure having an organic electroluminescent display portion (7).

An outline of the top emission type organic electroluminescence display device in Examples 17 to 19 is shown in FIGS. 14a and 14b. FIG. 14A is an explanatory diagram for explaining an outline of an organic light emitting display device according to a top emission type embodiment, and FIG. 14B is an explanatory diagram when FIG. 14A is viewed from a plane.
As shown in FIG. 14 a, a light scattering layer 23 is disposed on a light emitting portion (pixel) 21 having a maximum side length A, and a hemispherical lens 22 is disposed on the light scattering layer 23. In the example of FIG. 14a, the light scattering layer 23 is formed as an annular layer having an opening in a circular region centered on the central axis of the hemispherical lens 22 (see FIG. 14b).

As described above, in Examples 1 to 19 described above, an organic electroluminescence display device having a pixel of one color of green (about 530 nm) was manufactured. By appropriately changing the material of the light emitting layer, blue (about 470 nm) and An organic light emitting display having red (about 630 nm) pixels can be manufactured, and a full color organic light emitting display having three red, green, and blue pixels can be manufactured.
That is, when a device having three pixels of RGB of red (R), green (G), and blue (B) is manufactured, when a hemispherical lens is arranged for RGB3 pixels, as shown in FIG. Each pixel of the pixels may be surrounded by a hemispherical lens, or as shown in FIG. 11, the RGB3 pixels may be surrounded by a hemispherical lens as a unit, and as shown in FIG. A lens array having a plurality of hemispherical lenses may be arranged for each pixel. As shown in FIG. 13, when the pixel is not a square and is a rectangle with different side lengths, the longer side is adopted as the maximum length A of one side of the light emitting layer (light emitting layer).

  In addition, if the diameter φ of the hemispherical lens is too larger than the maximum length A of one side of the light emitting layer, the aperture ratio when the display is formed decreases, so the opening of the organic light emitting display device shown in FIG. The rate (B / M) is preferably 30% or more.

In Examples 1 to 16, a bottom emission type organic electroluminescence display device in which the maximum length A of one side of the light emitting layer (light emitting layer) was 2 mm (square shape: 2 mm □) was manufactured. The optical properties are equivalent if A / φ, which is the ratio to the diameter φ of the hemispherical lens, and the distance d between the light emitting layer (pixel) and the hemispherical lens are maintained.
Actually, the organic light emitting display device was manufactured so that the maximum length A of one side of the light emitting layer (light emitting layer) was 200 μm (square shape: 200 mm □), and the A / φ and the d were maintained. The same characteristics were obtained. At this time, an experiment was performed using a glass substrate having a thickness of 20 μm (d = 20 μm) as a glass substrate having a distance d.

In Examples 17 to 19, a top emission type organic electroluminescence display device in which the maximum length A of one side of the light emitting layer (light emitting layer) was 2 mm (square shape: 2 mm × 2 mm) was manufactured. And A / φ which is the ratio of the diameter of the hemispherical lens to the diameter φ of the hemispherical lens, the optical properties are equivalent.
Actually, an organic light emitting display device was manufactured so that the A / φ was maintained with the maximum length A of one side of the light emitting layer (light emitting layer) set to 200 μm (square shape: 200 μm × 200 μm), and similarly evaluated. However, the same characteristics were obtained.
In addition, the measuring method of the brightness | luminance in the organic electroluminescent display apparatus in Examples 1-19 and Comparative Examples 1-11 and the measuring method of light extraction efficiency are shown below.

<Measurement method of brightness>
A silicon detector is attached to the goniometer, each organic EL element is caused to emit light, the relationship between the angle of the goniometer and the voltage signal corresponding to the light intensity from the detector is measured, and the light distribution is obtained. The luminance was determined from the light intensity at an angle of 0 degrees.

<Measurement method of light extraction efficiency>
A hemispherical lens having a diameter sufficiently larger than the light emitting area and a refractive index of 1.8 is attached to the EL element, and light of all angle components is captured using an integrating sphere to measure the light intensity. The light intensity at this time is 1. Using the integrating sphere as the target measuring element, light of all angle components is taken in and the light intensity is measured. The light intensity at this time is the light extraction efficiency.

  The organic electroluminescence display device of the present invention is excellent in light extraction efficiency and has high front luminance. Therefore, it is suitable for both a bottom emission type organic electroluminescence display device and a top emission type organic electroluminescence display device. For example, computers, in-vehicle displays, outdoor displays, household equipment, commercial equipment, home appliances, traffic-related displays, clock displays, calendar displays, luminescent screens, acoustic equipment, etc. Can be suitably used in various fields including the above.

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Electron injection layer 8 Cathode 9, 22 Hemispherical lens 10 Barrier layer 21 Light emitting part (pixel)
23 Light-scattering layer 1, 50, 60, 70, 80, 100, 200 Organic electroluminescent display device 101, 201 Organic electroluminescent element

Claims (16)

An organic electroluminescent device having at least a light emitting layer, a hemispherical lens disposed on the light extraction surface side, and a light scattering layer for scattering light emitted from the light emitting layer between the light emitting layer and the hemispherical lens possess the door, the light scattering layer, the hemispherical lens is arranged in the region corresponding to the internal peripheral edge of the hemispherical lens on the surface to be supported, a circular region around the central axis of the hemispherical lens An organic electroluminescent display device, characterized by being an annular layer having an opening .   2. The organic electroluminescence display device according to claim 1, wherein the light scattering layer is any one of a fine particle scattering layer and a concavo-convex structure layer having irregularities arranged periodically or aperiodically. The fine particle scattering layer has fine particles and a binder, and the fine particles are TiO. ₂ The organic electroluminescent display device according to claim 2, which is any one of fine particles, ZnO fine particles, ZnS fine particles, and ZrO fine particles. The organic electroluminescent display device according to claim 3, wherein the binder has a refractive index of 1.54 to 2.2. The organic electroluminescent display device according to claim 2, wherein the fine particle scattering layer has a thickness of less than 1.0 μm. The organic electroluminescent display device according to claim 2, wherein the concavo-convex structure layer has a pitch interval of 0.7 μm to 2 μm. The organic electroluminescence display device according to claim 2, wherein the convex portion of the concavo-convex structure layer has a height of 0.35 μm to 2 μm. The organic electroluminescence display device according to claim 2, wherein the convex portion of the concavo-convex structure layer has a width of 0.3 μm to 1.6 μm. The contact area between the light scattering layer and the hemispherical lens on the support surface on which the hemispherical lens is supported is 15% to 95% of the area in the supported region of the hemispherical lens as 100%. 9. The organic electroluminescent display device according to any one of 8 above. The area of a pixel formed on the light extraction surface is 0.3 times or more with respect to a minimum area in a rectangular region surrounding the support surface that supports the hemispherical lens. Organic electroluminescent display device. A transflective electrode disposed on the light extraction surface side; and a reflective electrode layer disposed on a surface opposite to the transflective electrode with the light emitting layer interposed therebetween, and the light emitted from the light emitting layer The organic light emitting display device according to claim 1, further comprising a microcavity structure that causes interference between the transflective electrode and the reflective electrode to be emitted from the light extraction surface. The organic electroluminescent display according to claim 1, further comprising: a transmissive electrode disposed on a light extraction surface side; and a reflective electrode layer disposed on a surface opposite to the transmissive electrode via a light emitting layer. apparatus. When the microcavity structure is primary, the radius of the hemispherical lens is R, and the radial width of the hemispherical lens of the light scattering layer is a, the relationship between a and R is expressed by the following equation: The organic electroluminescent display device according to claim 11, satisfying a relationship of 0.3 ≦ a / R ≦ 0.5. When the microcavity structure is secondary, the radius of the hemispherical lens is R, and the radial width of the hemispherical lens of the light scattering layer is a, the relationship between a and R is expressed by the following equation: The organic electroluminescent display device according to claim 11, satisfying a relationship of 0.3 ≦ a / R ≦ 0.6. When the microcavity structure is tertiary, the radius of the hemispherical lens is R, and the radial width of the hemispherical lens of the light scattering layer is a, the relationship between a and R is expressed by the following equation: The organic electroluminescent display device according to claim 11, satisfying a relationship of 0.4 ≦ a / R ≦ 0.7. When the radius in the hemispherical lens is R and the radial width of the hemispherical lens in the light scattering layer is a, the relationship between a and R is expressed by the following formula: 0.4 ≦ a / R ≦ 1 The organic electroluminescent display device according to claim 12, satisfying the relationship: