JP2007287697A - Organic electroluminescent element and light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element which can improve a characteristic of a visibility angle and is excellent in color purity. <P>SOLUTION: In the organic electroluminescent element 1 provided with a pair of electrodes 13, 14 and an organic electroluminescent layer 15 pinched by these electrodes 13, 14, a light dispersing color filter 11 having a light dispersing property is arranged on the light taking-out side of the organic electroluminescent layer 15. Since light in all angles emitted from the organic light emitting layer 15 can be dispersed and mixed, color changes caused by viewing angles can be greatly reduced and color purity can be improved. When the organic electroluminescent element 1 is applied to a light emitting device, the light emitting device with excellent characteristics of a visibility angle and color purity can be obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element including a pair of electrodes facing each other and an organic light emitting layer sandwiched between the electrodes, and a light emitting device using the organic electroluminescence element.

Organic electroluminescence elements using electroluminescence (hereinafter referred to as organic EL elements) are self-luminous and have high visibility, and because they are completely solid elements, they have excellent impact resistance. The use as an element attracts attention.
An organic EL element has an element configuration in which an organic light emitting layer is sandwiched between a transparent electrode provided on a transparent substrate made of glass or the like and a counter electrode provided to face the transparent electrode, and the organic light emitting layer emits light transparently. It is designed to be taken out through the substrate.
In general, the transparent electrode is made of ITO (indium tin oxide) or the like, and the surface of the counter electrode on the side of the organic light emitting layer is often a mirror surface in order to increase the light emission efficiency.

  As a method of performing multicolor display using such an organic EL element, (1) a method of arranging a color filter on the display side of a white organic light emitting layer to divide white light into red, green and blue pixels. (See Patent Document 1), (2) A method of arranging pixels of three colors using organic light emitting layers of three colors of red, green, and blue on a substrate (see Patent Document 2), (3) and (2) In this method, in order to improve color purity, a method of arranging a color filter corresponding to the color of each pixel (see Patent Document) is known.

JP-A-7-142169 JP-A-8-227276 JP-A-8-321380

However, there is usually a difference in refractive index between the transparent electrode and the transparent substrate due to the difference in material, and the surface on the organic light emitting layer side of the counter electrode is a mirror surface. There is a problem of blue shifting (bluening) depending on the viewing angle, that is, the viewing angle.
In particular, when the organic EL element is applied to a multicolor display device, the blue pixel becomes more blue, the red pixel becomes orange, and the green pixel becomes blue, depending on the viewing angle, and the above (1) to (3) Regardless of which method is used, there arises a problem that the color balance is shifted and the white balance is lost.
In the methods (1) and (3), the color purity can be improved by the color filter, but the viewing angle dependency that the color changes depending on the viewing angle, that is, the viewing angle characteristic cannot be improved.

  An object of the present invention is to provide an organic EL element and a light-emitting device that can realize improvement in viewing angle characteristics and have excellent color purity.

The present invention intends to achieve the object by providing a light diffusing means together with a color filter.
Specifically, an organic electroluminescence device comprising a pair of electrodes facing each other and an organic light emitting layer sandwiched between these electrodes, wherein a color filter and a light diffusing element are disposed on the light extraction side of the organic light emitting layer. Means are provided.

Here, the light diffusing means has a function of diffusing light, and the light emitted from the organic light emitting layer can be scattered by the light diffusing means. That is, since the light emission of the organic light emitting layer can be scattered from one direction to multiple directions, light of all angles emitted from the element can be scattered and mixed, so that the color change due to the viewing angle can be remarkably reduced. Accordingly, the viewing angle characteristics can be remarkably improved, the color tone can be prevented from being shifted, and the white balance can be reliably maintained.
Further, since the color filter is provided together with the light diffusing means, the color purity of the light can be increased, and reflection of external light can be suppressed.

The configuration of the light diffusing unit is not particularly limited, but the light diffusing unit and the color filter are preferably configured by a light diffusing color filter in which the color filter contains a light diffusing material having a refractive index different from that of the color filter. .
In this way, by using a light diffusive color filter containing a light diffusing material and imparting light diffusibility, it is not necessary to provide a color filter and a light diffusing unit separately, so that the element configuration can be simplified. In addition, manufacturing can be facilitated.

The light diffusing means may be constituted by a light diffusing layer laminated on a color filter. The light diffusing layer is a transparent resin and a light diffusing material having a refractive index different from that of the transparent resin. It is preferable to have a material.
In this way, an element can be easily configured using an existing color filter.

Here, the light diffusing material described above is preferably made of at least one selected from inorganic fine particles, inorganic fillers and inorganic powders.
In this case, the inorganic fine particles, the inorganic filler, and the inorganic powder may be used singly or may be appropriately mixed and used. Moreover, a single material may be used, or a plurality of types of materials may be mixed and used.

  Furthermore, the light diffusing means may be constituted by a light diffusing surface having irregularities. In this way, the interface of the element, for example, the interface of the organic layer constituting the element, the interface between the organic layer and the electrode, or the electrode and the substrate when the electrode is provided on the substrate, remains in the existing element configuration. A light diffusing means can be easily constructed simply by forming a light diffusing surface at the interface.

The position of the light diffusion surface is not particularly limited as long as it is on the light extraction side of the organic light emitting layer, but when a color filter is provided on the substrate, the surface of the substrate can be the light diffusion surface.
Thus, by making the surface of the substrate a light diffusing surface, it is possible to easily form the light diffusing surface only by polishing the surface of the substrate or attaching fine particles to the surface of the substrate.

  Alternatively, the surface of the color filter on the side of the organic light emitting layer may be a light diffusing surface. According to this, since light is scattered and then incident on the color filter, it is diffused when color filters of different colors are arranged adjacent to each other. Since only necessary color light can be surely extracted from each light by the color filter of each color, an image having excellent color purity and no pixel blur can be obtained.

On the other hand, the light-emitting device of the present invention includes a pair of electrodes facing each other and an organic light-emitting layer sandwiched between these electrodes, and an organic light-emitting device provided with a color filter and light diffusion means on the light extraction side of the organic light-emitting layer. The EL element is two-dimensionally arranged, and the change of the CIE chromaticity coordinate according to the viewing angle is 0.02 or less.
In this way, by applying the above-described organic EL element to a light-emitting device and changing the CIE chromaticity coordinate depending on the viewing angle to 0.02 or less, a light-emitting device that is particularly excellent in viewing angle characteristics and color purity can be obtained.
Here, the viewing angle refers to an angle when viewing the display surface of the light emitting device.

As described above, according to the present invention, in an organic electroluminescent device including a pair of electrodes and an organic light emitting layer sandwiched between these electrodes, a color filter and a light are provided on the light extraction side of the organic light emitting layer. Since the diffusing means is provided, the light emitted from the organic light emitting layer can be scattered, and the light emitted from the element can be scattered and mixed, so that the color change due to the viewing angle can be remarkably reduced. Accordingly, the viewing angle characteristics can be remarkably improved, the color tone can be prevented from being shifted, and the white balance can be reliably maintained.
Further, since the color filter is provided together with the light diffusing means, the color purity of the light can be increased, and reflection of external light can be suppressed.

  On the other hand, a light-emitting device in which such organic EL elements are two-dimensionally arranged to constitute a light-emitting device, and the change in the CIE chromaticity coordinates depending on the viewing angle is 0.02 or less, so that the light-emitting device particularly excellent in viewing angle characteristics and color purity Is obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First embodiment]
<1> Organic EL Element FIG. 1 shows an organic EL element 1 of the present embodiment. The organic EL element 1 of the present embodiment is a light diffusing unit that uses a light diffusing color filter 11.
The light diffusing color filter 11 is provided on a transparent substrate 12, and on the light diffusing color filter 11, a transparent electrode (anode) 13, a counter electrode (cathode) 14 facing the transparent electrode 13, An organic light emitting layer 15 sandwiched between these electrodes 13 and 14 is laminated.
Although not shown, a hole injection layer or a hole transport layer may be provided between the organic light emitting layer 15 and the transparent electrode 13, and between the organic light emitting layer 15 and the counter electrode 14, an electron An injection layer or an electron transport layer may be provided.
In such an organic EL element 1, light emitted from the organic light emitting layer 15 (arrow 15A in FIG. 1) passes through the transparent electrode 13 and enters the light diffusing color filter 11, and this light diffusing color filter 11 is scattered through the transparent substrate 12.

The light diffusing color filter 11 is obtained by dispersing a light diffusing material 111 having a refractive index different from that of an existing color filter, and the difference in refractive index is preferably 0.1 or more. .
Specific examples of the color filter include a solid state color filter in which a colorant such as a dye or pigment is dissolved or dispersed in a binder resin, or a color filter mainly composed of a colorant. it can.
As the light diffusing material 111, the colorant and the binder resin used for the light diffusing color filter 11 of the present embodiment, the following can be adopted.

(A) Light diffusing material The light diffusing material can be composed of at least one selected from inorganic fine particles, inorganic fillers and inorganic powders.
The material of the light diffusing material is not particularly limited, and for example, an inorganic oxide, an inorganic fluoride, an inorganic sulfide, an inorganic carbonate, etc. can be adopted, and particularly preferably titania, zirconia, barium sulfate, calcium sulfate, Examples thereof include magnesia, barium carbonate, barium oxide, calcium oxide, barium titanate, and zinc oxide.
Further, when inorganic fine particles are employed as the light diffusing material, the particle diameter is preferably 0.3 μm to 3 μm.
As another preferable light diffusing agent, polymer fine particles, a transparent resin having a refractive index difference with a color filter or a refractive index difference with a transparent resin can be 0.1 or more, and these may be used alone, You may blend.

(B) Red [R] colorant Perylene pigments, lake pigments, azo pigments, quinacridone pigments, anthraquinone pigments, anthracene pigments, isoindoline pigments, isoindolinone pigments, or the like A mixture of at least two of them can be used.
(C) Green [G] colorant Single product such as halogen multi-substituted phthalocyanine pigment, halogen multi-substituted copper phthalocyanine pigment, trifelmethane basic dye, isoindoline pigment, isoindolinone pigment, or the like A mixture of at least two of them can be used.
(D) Blue [B] colorant A single product of a copper phthalocyanine pigment, an indanthrone pigment, an indophenol pigment, a cyanine pigment, a dioxazine pigment, or a mixture of at least two of these. it can.

(E) Binder resin It is preferable to use a transparent material (transmittance of 50% or more in the visible light region) as the binder resin.
Specific examples include transparent resins (polymers) such as polymethyl methacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, and carboxymethyl cellulose, and one of these may be used alone. Or you may use it, mixing 2 or more types.
Further, when the light diffusing color filter 11 is separated and arranged in a plane for pixel formation or the like, it is preferable to use a photosensitive resin to which a photolithography method can be applied as the binder resin. Specific examples include photo-curable resist materials having reactive vinyl groups such as acrylic acid, methacrylic acid, polyvinyl cinnamate, and cyclized rubber, and one of these is used alone. Alternatively, two or more kinds may be mixed and used.
When the color filter is separated and arranged in a plane by a printing method, a printing ink (medium) using a transparent resin can be used. Examples of the printing ink include polyvinyl chloride resin, polyvinylidene chloride resin, melamine resin, phenol resin, alkyd resin, epoxy resin, polyurethane resin, polyester resin, maleic acid resin, polyamide resin monomer, oligomer and polymer. Transparent resins such as a composition, polymethyl methacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, and carboxymethyl cellulose can be used alone or in admixture of two or more.

  Here, when the color filter for dispersing the light diffusing material is mainly composed of a colorant, the color filter can be formed by using vacuum deposition or sputtering through a mask of a desired color filter pattern. In this case, a light diffusing color filter can be formed by vacuum-depositing a light diffusing agent made of the above-described inorganic compound simultaneously with a color filter material such as a colorant.

On the other hand, when the color filter for dispersing the light diffusing material is made of a colorant and a binder resin, a general procedure for producing the color filter is as follows.
First, a liquid material is prepared by mixing, dispersing, or solubilizing a colorant, a binder resin, and an appropriate solvent. Thereafter, the liquid is formed into a film by a method such as spin coating, roll coating, bar coating, or casting. Then, after patterning a desired color filter pattern by a photolithography method, a printing method, or the like, a desired color filter is obtained by performing heat treatment and curing.
In this case, the light diffusing color filter can be produced by adding a light diffusing material to the liquid material.

  Moreover, when using a coloring agent and binder resin, it is preferable to set the concentration range of the coloring agent so that patterning can be easily performed and light emission of the organic EL element can be sufficiently transmitted. Accordingly, although depending on the type of the colorant, the content of the colorant in the light diffusing color filter film containing the binder resin to be used is preferably in the range of 5 to 50% by weight.

The transmittance of the light diffusing color filter may be appropriately set according to the color of the light to be extracted. For example, in the case of each of the light diffusing color filters of red, green, and blue, the transmittances of the following wavelengths respectively. It is preferable to set it to be 50% or more.
R (red): 610 nm
G (green): 545 nm
B (blue): 460 nm

  On the other hand, the organic light emitting layer 15 can be composed of various light emitting materials made of organic compounds. The light emission color of the organic light emitting layer 15 is not particularly limited, and a light emitting material may be appropriately selected according to the color of light to be extracted, the element configuration, and the like. Examples of the light emission color include white, blue, green, red, and the like. It is done.

<2> Light Emitting Device Next, the light emitting device 100 to which the organic EL element 1 is applied will be described. In the following description, the same components as those in FIG. 1 described above are denoted by the same reference numerals, and the description thereof is omitted or simplified.
The light emitting device 100 of this embodiment shown in FIGS. 2 and 3 is for performing color display, and has a plurality of striped transparent electrodes 13 arranged in parallel at a predetermined pitch on a transparent substrate 12, and the transparent A plurality of striped counter electrodes 14 arranged in parallel at a predetermined pitch on the electrode 13 and orthogonal to the transparent electrode 13, and the organic light emitting layer 15 sandwiched between the transparent electrode 13 and the counter electrode 14. Yes.

Between the transparent substrate 12 and the transparent electrode 13, striped light diffusing color filters 11R, 11G, and 11B are interposed along the transparent electrodes 13, respectively.
Between the adjacent light diffusing color filters 11R, 11G, and 11B, a stripe-shaped light shielding layer 16 (not shown in FIG. 2) is provided as a partition, and the light shielding layer 16 includes the light diffusing color filters 11R, 11G. , 11B or more.
The light shielding layer 16 and the light diffusing color filters 11R, 11G, and 11B are covered with a transparent protective layer 17, and the transparent electrode 13 is laminated on the protective layer 17.

The light diffusing color filters 11R, 11G, and 11B are respectively the light diffusing red filter 11R, the light diffusing green filter 11G, and the light diffusing blue that are configured using the red colorant, the green colorant, and the blue colorant described above. These three types of filters 11B are regularly arranged on the substrate 12.
Thereby, red, green, and blue monochromatic pixels are formed at the intersections of the transparent electrode 13 and the counter electrode 14, respectively.

In the light emitting device 100 of the present embodiment configured as described above, the light emitted from the organic light emitting layer 15 in each pixel passes through the transparent electrode 13 and the protective layer 17 and enters the light diffusing color filters 11R, 11G, and 11B, respectively. And pass through the transparent substrate 12.
At this time, since the thickness of the light shielding layer 16 is equal to or greater than the thickness of the light diffusing color filters 11R, 11G, and 11B, scattered light is adjacent to the light diffusing color filters 11R, 11G, and 11B of different colors. That is, since the light does not enter adjacent pixels, it is possible to prevent a decrease in color purity due to the color mixture of the light emission colors.

[Second Embodiment]
<1> Organic EL Element The organic EL element 2 of the present embodiment shown in FIG. 4 includes the light diffusing color filter 11 of the first embodiment as a light diffusing layer 21 and a color filter 22, and FIG. The same parts are denoted by the same reference numerals, detailed description thereof is omitted, and only different parts will be described in detail below.
The organic EL element 2 of the present embodiment includes a light diffusion layer 21 as a light diffusion means provided on a transparent substrate 12, and a color filter 22 laminated on the light diffusion layer 21, and this color filter A transparent electrode 13, an organic light emitting layer 15, and a counter electrode 14 are laminated on the layer 22 as in the first embodiment.
In such an organic EL element 2, light emitted from the organic light emitting layer 15 (arrow 15 </ b> A in FIG. 4) enters the light diffusion layer 21 through the transparent electrode 13 and the color filter 22 and is diffused in the light diffusion layer 21. And is taken out through the transparent substrate 12.

The light diffusion layer 21 can be configured by dispersing a light diffusion material 211 having a refractive index different from that of the transparent resin in the transparent resin. At this time, the refractive index difference between the light diffusing material 211 and the transparent resin is preferably 0.1 or more.
The light diffusing agent 211 can be configured using the same material as the light diffusing material 111 of the first embodiment.
As the transparent resin, the same transparent resin as the binder resin in the first embodiment can be used.
As the color filter 22, various existing color filters such as a color filter made of a binder resin and a colorant can be adopted as in the first embodiment.

  The order in which the light diffusion layer 21 and the color filter 22 are stacked may be reversed, and the light diffusion layer 21 may be provided on the color filter 22 formed on the substrate 12 as shown in FIG. .

<2> Light-Emitting Device Next, a light-emitting device 200 to which the organic EL element 2 is applied will be described. In the following description, the same components as those in FIGS. 1 to 5 described above are denoted by the same reference numerals, and the description thereof is omitted or simplified.
In the light emitting device 200 of the present embodiment shown in FIG. 6, striped color filters 22R, 22G, and 22B are interposed between the transparent substrate 12 and the transparent electrode 13 along each transparent electrode 13, and these colors are arranged. A striped light shielding layer 16 is provided between the filters 22R, 22G, and 22B.
The light diffusion layer 21 is interposed between the color filters 22R, 22G, and 22B and the light shielding layer 16 arranged in parallel as described above, and the transparent substrate 12, and the light transmitted through the color filters 22R, 22G, and 22B is transmitted. It is diffused by the light diffusion layer 21.

[Third embodiment]
<1> Organic EL Element The organic EL element 3 of this embodiment shown in FIG. 7 is provided with a light diffusion surface 31 by omitting the light diffusion layer 21 of the second embodiment, and FIG. 4 and FIG. The same parts are denoted by the same reference numerals, detailed description thereof is omitted, and only different parts will be described in detail below.
The organic EL element 3 of the present embodiment has an element configuration in which a color filter 22, a transparent electrode 13, an organic light emitting layer 15, and a counter electrode 14 are stacked in this order on a transparent substrate 12.

The surface of the transparent substrate 12 on the color filter 22 side is a light diffusing surface 31 having irregularities as light diffusing means, and diffuses and transmits light. The surface roughness of the light diffusion surface 31 is preferably 0.1 μm to 10 μm.
Such a light diffusion surface 31 can be formed by a method of polishing the surface of the transparent substrate 12 using a file or an abrasive, a method of attaching fine particles to the surface of the transparent substrate 12, or the like.

  In the organic EL element 3 of the present embodiment, since the refractive indexes of the color filter 22 and the transparent substrate 12 are different, light is scattered at the interface (light diffusion surface 31) between the color filter 22 and the transparent substrate 12 and passes through the transparent substrate 12. Emitted.

<2> Light Emitting Device FIG. 8 shows a light emitting device 300 to which the organic EL element 3 is applied. In the following description, the same components as those in FIGS. 1 to 7 described above are denoted by the same reference numerals, and the description thereof is omitted or simplified.
In the light emitting device 300 of the present embodiment, the surface of the transparent substrate 12 that is the interface with the color filters 22R, 22G, and 22B is the light diffusion surface 31, and the light that has passed through the color filters 22R, 22G, and 22B is the light diffusion surface 31. It is supposed to be diffused in

[Fourth embodiment]
The organic EL element 4 of the present embodiment shown in FIG. 9 and the light emitting device 400 of the present embodiment shown in FIG. 10 are obtained by changing the position of the light diffusion surface 31 of the third embodiment. The same parts are denoted by the same reference numerals, detailed description thereof is omitted, and only different parts will be described in detail below.
As shown in FIGS. 9 and 10, the surface of the color filter 22 on the organic light emitting layer 15 side is a light diffusing surface 41 having irregularities as light diffusing means, and diffuses and transmits light. . The surface roughness of the light diffusion surface 41 is preferably 0.1 μm to 10 μm.

In the present embodiment configured as described above, since the refractive index of the color filter 22 and the protective layer 17 thereon is different, light is scattered at the interface (light diffusion surface 41) between the protective layer 17 and the color filter 22. It passes through the transparent substrate 12.
In the organic EL element 4 shown in FIG. 9, the space between the color filter 22 and the transparent electrode 13 is a light diffusion surface 41. In the light emitting device 400 shown in FIG. 10, the color filters 22R, 22G, and 22B are protected. The light diffusing surface 41 is formed between the layer 17 and the light diffusing surface between the protective layer 17 and the transparent electrode 13 or the light diffusing between the transparent electrode 13 and the organic light emitting layer 15. It may be a surface.

The present invention is not limited to the above-described embodiments, and includes other configurations that can achieve the object of the present invention, and includes the following modifications and the like.
That is, in each of the above embodiments, the transmissive organic EL element and the light emitting device have been described. However, the present invention can also be applied to a reflective organic EL element and a light emitting device.
For example, as shown in FIG. 11, the light diffusive color filter 11 of the first embodiment may be incorporated in the organic EL element 5 that extracts light from the counter electrode 14 side. That is, the light diffusing color filter 11 may be provided on another transparent substrate 51 and laminated on the counter electrode 14. At this time, the space between the light diffusing color filter 11 and the counter electrode 14 may be hollow, may be filled with a dried liquid or gas, or may be provided with a translucent intermediate layer 52.

As the translucent intermediate layer 52, a transparent resin or a transparent inorganic compound can be employed. As the transparent resin, polyparaxylene and its derivatives, fluorine-based resins, silicon-based resins, and the like are preferable. In particular, polyparaxylene, its derivatives, and fluorine-based resins are used as a color filter solution when the light diffusing color filter 11 is provided. It is preferable because it is not attacked by. The transparent inorganic _{compound, SiO 2, SiO, MgO,} αSiN, inorganic oxides such as SiAlON, there inorganic nitride, alpha-C (amorphous carbon film), and the like.

  Instead of the light diffusing color filter, a light diffusing layer and a color filter similar to those in the second embodiment may be provided, or, as in the third embodiment, on the counter electrode 14 side of the substrate 51. The surface may be a light diffusing surface.

Next, the effect of this invention is demonstrated based on a specific Example.
[Example 1]
Example 1 is an experiment for producing a light emitting device including a light diffusing color filter based on the first embodiment.
<1> Light-shielding layer An acrylate-based photocurable resist V259PA in which 30% by weight (based on solid content) of carbon black is dispersed on a glass substrate (Corning 7059, 100 mm × 100 mm × 1.1 mm thickness) as a transparent support substrate ( Spin-coated with Nippon Steel Corporation and baked at 80 ° C. to form a resist film.
Thereafter, the resist film was exposed through a mask at a condition of 300 mJ / cm ² (365 nm) so as to obtain the light shielding layer pattern shown in FIG.
Subsequently, after developing for 2 minutes at room temperature using a 1% by weight aqueous sodium carbonate solution, baking was performed at 200 ° C., thereby patterning the light-shielding layer.
The film thickness of the obtained light shielding layer was 2.6 μm. Further, the cross-sectional shape of the light shielding layer was confirmed to be a rectangular shape by an electron microscope (SEM).
Further, the transmittance of this light shielding layer was confirmed by a spectrophotometer to be 10% or less in the wavelength region of 400 nm to 700 nm, and the reflectance was 5%.

<2> Light Diffusing Color Filter (1) Light Diffusing Blue Color Filter 28 wt% (based on solid content) of copper phthalocyanine pigment (CI Pigment Blue 15: 6) and 2 wt% (based on solid content) A dioxazine pigment (CI Pigment Violet 23) and 8% by weight of zinc oxide powder (average particle size 0.3 to 0.5 μm, 23-K, manufactured by Hakusui Chemical Co., Ltd.) This was dispersed in a type resist V259PA (manufactured by Nippon Steel Chemical Co., Ltd.), spin-coated on the substrate, and baked at 80 ° C.
Thereafter, as shown in FIGS. 2 and 3, the substrate and the mask are aligned so that a blue color filter pattern parallel to the light shielding layer is obtained, and an exposure machine using a high-pressure mercury lamp as a light source is used. The resist film was exposed under the condition of 300 mJ / cm ² (365 nm).
Next, after developing for 2 minutes at room temperature using a 1% by weight aqueous sodium carbonate solution, baking was carried out at 200 ° C. to form a light diffusing blue color filter pattern.
The film thickness of the obtained light diffusing blue color filter was 2.4 μm.
The refractive index of zinc oxide as a light diffusing material is 2.1, and the refractive index of the blue color filter excluding the zinc oxide powder is 1.50 (589 nm). It can be seen that the diffusible blue color filter has light diffusibility.

(2) Light diffusing green color filter 23 wt% (based on solid content) of copper halide phthalocyanine pigment (CI Pigment Green 36) and 7 wt% (based on solid content) azo pigment (C Pigment Yellow 83) and 2% by weight of zinc oxide powder are dispersed in an acrylate photocurable resist V259PA (manufactured by Nippon Steel Chemical Co., Ltd.) and spin coated on a substrate at 80 ° C. I baked.
Thereafter, in order to obtain the green color filter pattern shown in FIGS. 2 and 3, the substrate and the mask are shifted by 300 μm in a direction orthogonal to the blue color filter pattern, and the high pressure mercury lamp is used as the light source. The resist film was exposed under the condition of 300 mJ / cm ² (365 nm) using an exposure machine.
Next, after developing for 2 minutes at room temperature using a 1% by weight aqueous sodium carbonate solution, baking was carried out at 200 ° C. to form a light diffusing green color filter pattern.
The film thickness of the obtained light diffusing green color filter was 2.0 μm.
In addition, since the refractive index of zinc oxide as a light diffusing material is 2.1 and the refractive index of the green color filter without zinc oxide powder is 1.50 (589 nm), the light diffusion of Example 1 is performed. It can be seen that the neutral green color filter has light diffusibility.

(3) Light-diffusing red color filter 24% by weight (based on solid content) anthraquinone pigment (CI Pigment Red 177) and 6% by weight (based on solid content) azo pigment (CI pigment) Yellow 6) and 2% by weight of zinc oxide powder were dispersed in an acrylate photocurable resist V259PA (manufactured by Nippon Steel Chemical Co., Ltd.), spin-coated on a substrate, and baked at 80 ° C.
Thereafter, in order to obtain the red color filter pattern shown in FIGS. 2 and 3, the substrate and the mask are shifted by 300 μm in a direction orthogonal to the green color filter pattern, and the high pressure mercury lamp is used as the light source. The resist film was exposed under the condition of 300 mJ / cm ² (365 nm) using an exposure machine.
Next, after developing for 2 minutes at room temperature using a 1% by weight aqueous sodium carbonate solution, baking was performed at 200 ° C. to form a light diffusing red color filter pattern.
The film thickness of the obtained light diffusing red color filter was 2.1 μm.
In addition, since the refractive index of zinc oxide as a light diffusing material is 2.1 and the refractive index of a red color filter without zinc oxide powder is 1.50 (589 nm), the light diffusion of Example 1 is performed. It can be seen that the neutral red color filter has light diffusibility.

Through the above procedure, the light shielding layer, the light diffusing blue color filter, the light diffusing green color filter, and the light diffusing red color filter are separated on the substrate in a plane, and then the acrylate resin (Nippon Steel V259) was spin-coated on a substrate (on a color filter and a light shielding layer) and prebaked at 80 ° C., followed by baking at 180 ° C. to form a protective layer.
In Example 1, in order to confirm the light emission luminance and chromaticity of the organic light emitting layer, a part of the color filter was mechanically removed for convenience.

<3> Transparent electrode (anode)
A transparent electrode made of ITO was formed on each light diffusing color filter in a line from the top of the protective layer. The transparent electrode was an ITO pattern formed with a width of 90 μm and a gap of 20 μm.

<4> Hole injection layer, organic light emitting layer, electron injection layer, and counter electrode (cathode)
The substrate with the transparent electrode was ultrasonically cleaned with isopropyl alcohol and UV-cleaned, and then each organic layer and the counter electrode were evaporated using a vapor deposition apparatus (manufactured by Nippon Vacuum Technology Co., Ltd.).
That is, the substrate after cleaning is fixed to a substrate holder, and TPD74 and 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (hereinafter referred to as NPD) as a hole injection material, light emission As materials, 4,4'-bis (2,2-diphenylvinyl) biphenyl (hereinafter referred to as DPVBi) and 4,4'-bis (2- (4-N, N-diphenylamino) phenylvinyl) biphenyl (hereinafter referred to as DPVBi) , PAVBi), tris (8-quinolinol) aluminum (hereinafter referred to as Alq) as an electron injection material, and rubrene as an orange light emitting material in an electron injection layer, respectively, into a resistance heating boat made of molybdenum, and hole injection It was set as each vapor deposition source of a layer, an organic light emitting layer, and an electron injection layer.
Further, Ag was attached to a tungsten filament as a second metal of the counter electrode (cathode), and Mg was attached to a molybdenum boat as an electron injecting metal of the cathode to form a counter electrode deposition source.
The structural formula of TPD74 is as shown below.

Thereafter, the vacuum chamber was depressurized to 5 × 10 −7 torr, and the film formation was performed in the following order without breaking the vacuum from the formation of the hole injection layer to the formation of the counter electrode.
First, after depositing TPD74 at a deposition rate of 0.1 to 0.3 nm / s to a film thickness of 120 nm, NPD was deposited at a deposition rate of 0.1 to 0.3 nm / s to a film thickness of 20 nm. A hole injection layer having a two-layer structure was formed.
Next, DPVBi constituting the organic light emitting layer is deposited so as to have a film thickness of 50 nm at a deposition rate of 0.1 to 0.3 nm / s. At the same time, PAVBi is deposited at a deposition rate of 0.003 to 0.009 nm / s. It was vapor-deposited and contained in DPVBi.

Subsequently, as an electron injection layer, Alq was evaporated at a deposition rate of 0.1 to 0.3 nm / s to a film thickness of 20 nm, and rubrene was evaporated at a deposition rate of 0.0005 to 0.0015 nm / s. Co-deposited. Thus, the electron injection layer containing rubrene emits light when a voltage is applied.
Next, Mg and Ag were vapor-deposited simultaneously as a counter electrode. That is, Mg was evaporated at a deposition rate of 1.3 to 1.4 nm / s, and Ag was evaporated at a deposition rate of 0.1 nm / s to form a counter electrode having a thickness of 200 nm.
In addition, in order to form a cathode into the stripe form orthogonal to the ITO pattern as a transparent electrode, it formed the pattern by performing vapor deposition through a mask.

<5> Luminescence test When a DC voltage of 9 V was applied between the transparent electrode (anode) and the counter electrode (cathode) of the light-emitting device produced in this manner, the intersection between the transparent electrode and the counter electrode (300 μm × 90 μm) (Dot pattern) emitted light.
In addition, when the light emission luminance and chromaticity were measured in a portion where the light shielding layer and the color filter were previously cut, white light emission with light emission luminance of 70 cd / m ² , chromaticity x = 0.30, and y = 0.28 was obtained. Obtained.
On the other hand, blue light emission with a light emission luminance of 10 cd / m ² is obtained from the light diffusive blue color filter, and yellowish green (yellowish green) with a light emission luminance of 45 cd / m ² is obtained from the light diffusion green color filter. Light emission was obtained, and red light emission with a light emission luminance of 15 cd / m ² was obtained from the light diffusing red color filter.

[Comparative Example 1]
A light emitting device was produced in the same manner as in Example 1, except that the zinc oxide powder was omitted and a color filter having no light diffusibility was produced.

[Evaluation of light emitting device]
Light that emits light by applying a DC voltage of 9 V between the transparent electrode (anode) and the counter electrode (cathode) of each light-emitting device of Example 1 and Comparative Example 1, and passes through the red, green, and blue color filters. The change in chromaticity with viewing angle was investigated.
That is, as shown in FIG. 12, when the display surface 9 is viewed from the normal direction of the display surface 9 of the light emitting device (arrow 9A in FIG. 12) from the direction inclined by the angle (viewing angle) θ respectively in the vertical and horizontal directions. The chromaticities of red light, green light and blue light were measured respectively.
Here, the viewing angle θ is set to 0 ° and 70 °, the results of Example 1 at that time are shown in Table 1, and the results of Comparative Example 1 are shown in Table 2.

From Table 1, since the light-emitting device of Example 1 is provided with the light diffusive color filter, the change of the chromaticity coordinate is 0.02 or less when the viewing angle θ is 0 ° and 70 °. It can be seen that no significant color shift due to the viewing angle is observed, and that it can be sufficiently applied to a full-color display device.
On the other hand, from Table 2, since the color filter does not have the function of diffusing light in the light emitting device of Comparative Example 1, the color of light at the viewing angle θ = 70 ° is larger than the color at the viewing angle θ = 0 °. A blue shift was observed and a color shift effect was observed. This is considered to be because the emission wavelength is shortened by the interference effect by increasing the viewing angle θ. Therefore, it can be seen that the light-emitting device of Comparative Example 1 has a problem in application to a full-color display device although it is self-luminous.

[Example 2]
Example 2 is an experiment for producing a light-emitting device including a light diffusion layer based on the second embodiment, and is the same as Example 1 except that the following points are changed in Example 1. Thus, a light emitting device was manufactured.
That is, a color filter was prepared without using zinc oxide powder, and a light diffusion layer was provided on the color filter before providing a protective layer. The light diffusing layer was formed by dispersing the same zinc oxide powder as in Example 1 as the light diffusing agent in the acrylate resin V259, spin-coating it on the substrate, and baking at 80 ° C. . Next, an acrylate resin V259 not containing the zinc oxide powder was spin-coated on the light diffusion layer, pre-baked at 80 ° C., and baked at 200 ° C. to form a protective layer.
Thereafter, a transparent electrode, a hole injection layer, an organic light emitting layer, an electron injection layer, and a counter electrode were formed in the same manner as in Example 1 to obtain a light emitting device of Example 2.

  For the light emitting device of Example 2, as in Example 1 and Comparative Example 1, the chromaticity at the viewing angle θ = 0 ° and the chromaticity at θ = 70 ° were compared for each color and evaluated. As a result, the change in the CIE chromaticity coordinates was smaller than 0.02.

Example 3
Example 3 is an experiment for producing a light-emitting device having a light diffusion surface based on the fourth embodiment, and is the same as Example 1 except that the following points are changed in Example 1. Thus, a light emitting device was manufactured.
That is, in the same manner as in Example 1, a light-shielding layer was formed on a transparent substrate, a color filter was prepared without using zinc oxide powder, and the substrate with the color filter was polished by a tape polishing apparatus. A light diffusion surface having an average unevenness of 0.5 μm was formed on the surface of the filter.
Next, fluorine-substituted polyimide (refractive index: 1.54) was spin-coated on the light diffusion surface, and baked at 180 ° C. to form a protective layer. The refractive index difference between this protective layer and the color filter on which the light diffusion surface was formed was 0.1 or more.
A transparent electrode, a hole injection layer, an organic light emitting layer, an electron injection layer and a counter electrode are formed on such a substrate with a color filter in the same manner as in Example 1, and the light emitting device of Example 3 is obtained. Obtained.

  For the light emitting device of Example 3, as in Examples 1 and 2 and Comparative Example 1, the chromaticity at the viewing angle θ = 0 ° and the chromaticity at θ = 70 ° were compared for each color. As a result, the change in the CIE chromaticity coordinates was smaller than 0.02.

The figure which shows the organic EL element of 1st embodiment of this invention. The perspective view which shows the light-emitting device of said 1st embodiment. The figure which shows the light-emitting device of said 1st embodiment. The figure which shows the organic EL element of 2nd embodiment of this invention. The figure which shows the other organic EL element of said 2nd embodiment. The figure which shows the light-emitting device of said 2nd embodiment. The figure which shows the organic EL element of 3rd embodiment of this invention. The figure which shows the light-emitting device of the said 3rd embodiment. The figure which shows the organic EL element of 4th embodiment of this invention. The figure which shows the light-emitting device of the said 4th embodiment. The figure which shows the other organic EL element of this invention. The figure which shows the viewing angle of the light-emitting device in the Example of this invention.

Explanation of symbols

1,2,3,4,5 Organic electroluminescence device (organic EL device)
12, 51 Transparent substrate 13 Transparent electrode (anode)
14 Counter electrode (cathode)
15 Organic Light-Emitting Layer 11 Light Diffusing Color Filter (Light Diffusing Means)
11R light diffusing red filter (light diffusing means)
11G diffusive green filter (light diffusion means)
11B Light diffusing blue filter (light diffusing means)
22, 22R, 22G, 22B Color filter 21 Light diffusion layer (light diffusion means)
31, 41 Light diffusion surface (light diffusion means)
111, 211 Light diffusing material 100, 200, 300, 400

Claims (4)

An organic electroluminescence device comprising a pair of electrodes facing each other and an organic light emitting layer sandwiched between these electrodes,
On the light extraction side of the organic light emitting layer,
A color filter and light diffusing means;
A light shielding layer as a partition that separates the color filter and the light diffusion means for each adjacent pixel, and
The light diffusing means is composed of a light diffusing surface having irregularities, and is an organic electroluminescence element. In the organic electroluminescent element according to claim 1,
The light diffusing means is unevenness provided on a surface of a substrate. An organic electroluminescence element, wherein: In the organic electroluminescent element according to claim 1,
The said light-diffusion means is the unevenness | corrugation provided in the surface of the said color filter. The organic electroluminescent element characterized by the above-mentioned. In the organic electroluminescent element according to claim 1,
A protective layer in direct contact with the color filter is provided;
The difference between the refractive index of the said color filter and the refractive index of the said protective layer is 0.1 or more. The organic electroluminescent element characterized by the above-mentioned.

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