JP2009129586A - Organic el element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve high luminance and high color purity by carrying out high-efficiency light emission in a low-voltage drive in order to improve color reproducibility in a CCM system. <P>SOLUTION: Of an organic EL element capable of full-color display having organic EL light emission units equipped with an organic light-emitting layer emitting light of blue or blue-green color between opposed electrodes, the organic light emission units are electrically connected in two steps in parallel, a light path adjusting layer is formed at a green-color pixel area, and a color conversion layer is provided at a red-color pixel area. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic EL element. This organic EL element is capable of full-color display with high definition and excellent visibility, and has applicability to a wide range of screen displays such as portable terminals, industrial measuring instruments, and home televisions.

  As an example of a light emitting element applied to a display device, an organic EL light emitting element having a thin film laminated structure of an organic compound is known. Organic EL light-emitting elements are thin-film self-luminous elements and have excellent characteristics such as low driving voltage, high resolution, and high viewing angle, and various studies have been made for their practical use.

  The organic EL light emitting element has a structure including at least an organic light emitting layer between an anode and a cathode. The organic EL light-emitting element has a structure in which a hole injection layer, a hole transport layer, an electron transport layer and / or an electron injection layer are interposed as required. When a voltage is applied between the anode and the cathode, holes and electrons are injected into the organic EL light emitting device. The injected holes and electrons are recombined in the organic light emitting layer, and as a result, the organic EL material in the organic light emitting layer is raised to a high energy state. Light is emitted when the organic EL material transitions from a high energy state to a ground state.

  A display is configured by arranging many pixels in a matrix. There are various pixel matrix driving methods, but a method called simple matrix driving has a relatively simple configuration and is often used. A display that is driven by a simple matrix is characterized in that a plurality of rows of anodes and cathodes are formed in stripes, and the anode rows and the cathode rows are arranged orthogonal to each other. A specific signal is displayed on the pixel where the selected anode column and the selected cathode column intersect.

At present, attention has been focused on a CCM method combining a color conversion layer and a color filter as a full color method.
In the CCM method, for example, blue or blue-green light from an organic EL layer is absorbed by a fluorescent dye and converted into visible light having a wavelength longer than that of the light-emitting layer from green to red. It is superior in terms of color reproducibility compared to the RGB coating method in which the EL layer material is changed for each pixel of the fluorescent dye RGB, or the white color filter method in which a white light emitting EL element and a color filter are combined.

  However, in the CCM system, the conversion efficiency for obtaining red from blue or blue-green light emission is not so high, and in order to obtain a high red light emission intensity, it was necessary to increase the blue or blue-green light emission intensity. In order to increase the luminance, it is sufficient to increase the injection current, but this is not practical because the operating voltage of the element increases. Furthermore, there is a problem that the chromaticity of the green pixel is bad. In the first place, a green component is sufficiently contained in the emission color, and the contribution of the converted green color by CCM green is 20% or less, and the wavelength is also shorter than 520 to 550 nm which is a preferable range. Therefore, since the center wavelength of green is pulled by the green peak of the emission color and is on the short wavelength side, color reproducibility is not sufficient, and the NTSC ratio is as low as 80% or less. For example, in a conventional CCM system (using a blue-green emission spectrum, CCM green, and CCM red), RGB CIE chromaticity and efficiency are as follows: R (0.63, 0.36), 9 0.7 cd / A, G (0.25, 0.70), 65 cd / A, B (0.11, 0.16), 16 cd / A, and the current ratio is R: G: B = 50: 7: 27, NTSC ratio was 80%.

In order to improve the luminous efficiency and provide an organic EL device that emits white light with excellent light emission stability, several layers of devices have been proposed so far. For example, Patent Document 1 discloses that a two-color light emitting layer is formed between an anode and a cathode. Patent Document 2 discloses that a plurality of organic EL light emitting units are arranged in series between an anode and a cathode via an equipotential surface. Patent Document 3 discloses that organic EL light emitting elements that emit light of the same color are connected and stacked in parallel, thereby reducing the current density flowing through the light emitting elements and extending the life of the elements. ing.
JP-A-6-207170 JP 2003-456765 A JP-A-6-176870 JP 2001-76871 A US Pat. No. 5,937,272

As described in Patent Documents 1 and 2, when a plurality of organic EL light emitting units are arranged in series, the efficiency is improved, but there is a problem that the voltage increases.
As described in Patent Document 3, when organic EL light emitting elements that emit light of the same color are connected and stacked in parallel, the efficiency can be improved without increasing the voltage, but this configuration is applied to a CCM full color panel. There is no disclosure or suggestion about what to do.
On the other hand, for the CCM method, changing the ratio of the portion of the emission spectrum from the light emitting layer that is converted by CCM green and the conversion wavelength requires a great deal of material development and is not easy.

  In view of such circumstances, an object of the present invention is to realize high luminance and high color purity by emitting light with high efficiency in low voltage driving in order to improve color reproducibility in the CCM method.

  That is, the gist of the present invention is an organic EL element having an organic EL light emitting unit in which an organic light emitting layer for emitting blue or blue-green light is provided between opposing electrodes, wherein the organic light emitting unit includes the organic light emitting unit. The organic EL device is electrically connected in two stages in parallel, and an optical path adjustment layer is formed between the organic light emitting portion and the substrate in the green pixel region, and a color conversion layer is provided in the red pixel region. In the element.

According to the present invention, it is possible to improve the light emission efficiency of the device without increasing the voltage by arranging the organic light emitting units in a stacked parallel manner. High luminance blue can be obtained if it is extracted from the blue color filter using the light emitted from the blue-green light emitting part with improved luminous efficiency as it is, while it is absorbed by the color conversion layer and extracted from the red color filter. A red color can be obtained. The green pixel portion includes an optical path adjustment layer, and the wavelength distribution of blue-green light emission is changed by using resonance between the optical path adjustment layer and the reflective electrode on the opposite side of the light emitting side of the organic light emitting portion. The shape of the emission spectrum can be adjusted to improve chromaticity and luminance.
That is, according to the present invention, in the CCM organic EL display, it is possible to increase the luminance of blue, green, and red and improve the color purity.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a laminate 100 which is a basic configuration of the organic EL element of the present invention.

  A laminated body 100 shown in FIG. 1 includes a first light emitting unit 1, a second light emitting unit 2, and an intermediate electrode unit 3 inserted therebetween. The first light emitting unit 1 includes a first transparent electrode on which a black matrix 112, a color filter 113, a planarization layer 114, a color conversion layer 115, an optical path adjustment layer 116, and a passivation layer 117 are formed on a transparent substrate 111. 121, a first interlayer insulating film 122 defining a pixel region, a first organic EL layer 123, and a first metal thin film 124 are sequentially formed. In the second light emitting unit, a second metal electrode 221, a second interlayer insulating film 222 defining a pixel region, a second organic EL layer 223, and a second metal thin film 224 are sequentially formed on a substrate 211. The intermediate electrode unit 3 includes transparent conductive films 312 and 322 formed on both surfaces of a transparent substrate 311. The two transparent conductive films are electrically joined by a conductor filled in the through hole 331. The first transparent electrode 121 of the first light emitting unit and the second metal electrode 221 of the second light emitting unit are formed in stripes extending in the same direction, and the transparent conductive film of the intermediate electrode unit 3 is orthogonal to the above. It is formed in a stripe shape in the direction.

Each component constituting the laminate 100 will be described.
1. First light emitting unit 1
1.1 Color filter 113
The color filter 113 used in the device of the present invention may be a color filter used for a flat panel display such as a liquid crystal display. In recent years, a pigment dispersion type color filter in which a pigment is dispersed in a photoresist is often used.

  The color filter for the flat panel display includes a blue color filter that transmits a wavelength of 400 nm to 550 nm, a green color filter that transmits a wavelength of 500 nm to 600 nm, and a red color filter that transmits a wavelength of 600 nm or more. In general, a black matrix 112 that does not transmit the visible region is generally disposed between the color filter pixels mainly for the purpose of improving the contrast.

1.2 Planarization layer 114
The flattening layer 114 of the color filter is disposed for the purpose of protecting the color filter and for the purpose of smoothing the film surface, has a high light transmittance, and is disposed without degrading the color filter. It is necessary to select materials and processes that can be installed. Further, when a transparent conductive film or the like is formed on the upper surface of the color filter, it is further required to have sputtering resistance.

  As described above, since the planarization layer has a purpose of smoothing, it is generally formed by a coating method. In this case, as a material that can be applied, a photocurable or photothermal combination type curable resin is subjected to light and / or heat treatment to generate radical species or ionic species to be polymerized or crosslinked to be insoluble and infusible. Is common. Further, it is desirable that the photocurable or photothermal combination type curable resin is soluble in an organic solvent or an alkali solution before curing for patterning the fluorescent color conversion layer.

  Specifically, the photocurable or photothermal combination type curable resin means (1) a composition film comprising an acrylic polyfunctional monomer and oligomer having a plurality of acryloyl groups and methacryloyl groups, and light or a thermal polymerization initiator. (2) a composition obtained by polymerizing by generating photoradicals or thermal radicals by heat treatment, (2) a composition comprising polyvinyl cinnamate ester and sensitizer dimerized by light or heat treatment, and (3) chain A composition film composed of a cyclic or cyclic olefin and bisazide is generated by light or heat treatment to generate nitrene and crosslinked with the olefin, and (4) a composition film composed of a monomer having an epoxy group and a photoacid generator is subjected to light or heat treatment. In other words, the acid (cation) is generated and polymerized. In particular, the photocurable or photothermal combination type curable resin (1) can be patterned with high definition, and is preferable in terms of reliability such as solvent resistance and heat resistance.

  Others such as polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone, polyvinyl butyral, polyphenylene ether, polyamide, polyetherimide, norbornene resin, methacrylic resin, isobutylene maleic anhydride copolymer resin, cyclic olefin Thermosetting resins such as thermoplastic resins, epoxy resins, phenol resins, urethane resins, acrylic resins, vinyl ester resins, imide resins, urethane resins, urea resins, melamine resins, polystyrene, polyacrylonitrile, polycarbonate, etc. And a polymer hybrid containing trifunctional or tetrafunctional alkoxysilane can be used.

1.3 Color conversion layer 115
In the present invention, the organic fluorescent dye used for the color conversion layer (organic fluorescence conversion layer) 115 preferably includes a first dye and a second dye. The color conversion layer has a thickness of 1 μm or less, the first dye absorbs light incident on the color conversion layer and transfers the energy to the second dye, and the second dye The first dye is present in the color conversion layer 115 in an amount capable of sufficiently absorbing the incident light, and the second dye is the color conversion layer 115. Preferably, it is present in an amount of 10 mol% or less, preferably 0.1 to 5 mol%, based on the total number of constituent molecules. Here, the first dye is preferably present in an amount of 50 to 99.99 mol% based on the total number of constituent molecules of the color conversion layer 115. The color conversion layer 115 is formed by a vapor deposition method.

  The first dye absorbs light incident on the color conversion layer 115, preferably blue to blue-green light emitted from the organic EL element, and moves the absorbed energy to the second dye. Therefore, it is desirable that the absorption spectrum of the first dye overlaps with the emission spectrum of the organic EL element, and the absorption maximum of the first dye overlaps with the maximum of the emission spectrum of the organic EL element. Is more desirable. In addition, it is desirable that the emission spectrum of the first dye overlaps with the absorption spectrum of the second dye, and the maximum of the emission spectrum of the first dye overlaps with the absorption maximum of the second dye. Is more desirable. Dyes that can be suitably used as the first dye in the present invention include 3- (2-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6), 3- (2-benzimidazolyl) -7-diethylaminocoumarin (coumarin 7), Contains coumarin dyes such as coumarin 135. Alternatively, naphthalimide dyes such as Solvent Yellow 43 and Solvent Yellow 44 may be used as the first dye. The first dye is desirably present in an amount of 50 to 99.99 mol% based on the total number of constituent molecules of the color conversion layer 115. By existing in such a concentration range, it is possible to sufficiently absorb the incident light of the color conversion layer 115 and transfer the absorbed light energy to the second dye.

1.4 Optical path adjustment layer 116
The optical path adjustment layer 116 is a layer for resonating light emitted from the first organic EL layer 123 and the second organic EL layer 223, and includes a half mirror layer and a dielectric layer.
By providing the optical path adjustment layer 116 on the flattening layer 114, resonance is caused with both the half mirror layer of the optical path adjustment layer 116 and the second metal electrode 221 as both ends. Converts to longer wavelength light, resulting in enhanced longer wavelength light.
There is a relationship of the following formula (I) between the optical film thickness (nd) between the two reflective interfaces and the wavelength (λ) of light desired to be enhanced by resonance.
(Nd) × (4π / λ) + φ = 2mπ (I)
Here, φ indicates the sum of phase changes given by reflections generated at two reflective interfaces. For example, when one reflective interface is given by a metal, it is known that φ contributes by π. . m is an integer of 1-10.
In the present invention, resonance is caused with the second metal electrode 221 as one end and the half mirror layer as the other end to resonate green light (wavelength 500 nm to 550 nm), increase stimulated emission of green light, and Make it rich. In order to cause resonance with long-wavelength side light, an optical path adjustment layer 116 is inserted for optical path adjustment for increasing the optical path length.
As the half mirror layer, a highly reflective metal or alloy such as Ag or MgAg is used, and the thickness is 10 nm to 50 nm. A dielectric layer formed of a material such as SiN, SiO, TiO ₂ , Ta ₂ O ₅ , ITO, or IZO is used for optical path adjustment.

1.5 Passivation layer 117
For the purpose of protecting the organic EL layers 123, 223 and the like from moisture generated from the color filter 113, a passivation layer 117 may be laminated on the upper surface of the planarizing layer 114. The passivation layer 117 is required to be a transparent and dense pinhole film, such as inorganic oxides such as SiO _x , SiN _x , SiN _x O _y , AlO _x , TiO _x , TaO _x , and ZnO _x , inorganic nitride, etc. Can be used. There is no restriction | limiting in particular as a formation method of the passivation layer 117, It can form by common methods, such as a sputtering method, CVD method, a vacuum evaporation method, a dip method. The thickness of the passivation layer 117 is preferably 100 to 300 nm.

1.6 First transparent electrode 121
The first transparent electrode 121 is preferably an amorphous film made of a transparent conductor such as IZO (indium zinc oxide) or ITO (indium tin oxide) by sputtering, for example. The film thickness is preferably 100 to 300 nm.

1.7 First interlayer insulating film 122
On the first transparent electrode 121 pattern, an interlayer insulating film 122 provided with an opening in a portion where the first organic EL layer 123 is provided is formed on the entire surface of the substrate. The interlayer insulating film 122 is formed so as to cover the end of the first transparent electrode 121 in the opening. The edge of the first transparent electrode 121 is a portion where electric field concentration is likely to occur because the electrode shape changes abruptly, and the first organic light emitting layer 123 breaks down, resulting in the first transparent electrode 121 occurring as a result. In some cases, a display defect may occur due to a short circuit between the electrode and the electrode provided thereon, but this can be prevented by the interlayer insulating film. As the interlayer insulating film 122, an organic material such as polyimide or novolac resin, or an inorganic material such as silicon oxide or silicon nitride can be used.

1.8 First organic EL layer 123
The first organic EL layer 123 includes at least an organic light emitting layer, and includes an electron injection layer, an electron transport layer, a hole transport layer, and / or a hole injection layer as necessary. Specifically, when including the anode and the cathode, those having the following layer structure are adopted.
(A) Anode / organic light emitting layer / cathode (b) anode / hole injection layer / organic light emitting layer / cathode (c) anode / organic light emitting layer / electron injection layer / cathode (d) anode / hole injection layer / organic Light emitting layer / electron injection layer / cathode (e) anode / hole injection layer / hole transport layer / organic light emitting layer / electron injection layer / cathode (f) anode / hole transport layer / organic light emitting layer / electron transport layer / Cathode (g) Anode / hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection layer / cathode

The material of each layer in the first organic EL layer 123 is not particularly limited, and known materials can be used. The hole transport layer may use α-NPD, and may be doped with a Lewis acid compound such as F4-TCNQ. The material of the organic light emitting layer can be selected according to the desired color tone. For example, in order to obtain light emission from blue to blue-green, fluorescence such as benzothiazole, benzimidazole, and benzoxazole is used. Brightening agents, styrylbenzene compounds, aromatic dimethylidin compounds, and the like can be used. Alternatively, the organic light emitting layer may be formed using a host-guest material containing a host material and a blue dopant. As host materials, aluminum chelate, 4,4′-bis (2,2′-diphenylvinyl), 2,5-bis (5-tert-butyl-2-benzoxazolyl) -thiophene (BBOT), biphenyl (DPVBi) is used. Blue dopants include perylene, 2,5,8,11-tetra-t-butylperylene (TBP), 4,4′-bis [2- {4- (N, N-diphenylamino) phenyl} vinyl] It is used that 0.1 to 5% of biphenyl (DPAVBi) is added. Alq ₃ can be used for the electron transport layer, and it may be doped with an alkali metal such as Li.
The film thicknesses of the first organic EL layer 123 and the second organic EL layer 223 can be appropriately selected in consideration of the driving voltage, transparency, and the like. Usually, the hole transport layer has a thickness of 20 to 150 nm, and organic light emission. The layer is 20 to 40 nm, and the electron transport layer is 20 to 40 nm. However, it is not limited to these. The first organic EL layer 123 can be formed using any means known in the technical field, such as a vapor deposition method.

  The first organic EL layer may be formed by vacuum deposition using a mask vapor deposition method (a method in which vapor deposition is performed by covering a portion other than a portion to be vapor deposited with a mask), or a sheet on which an organic EL material has been previously formed is attached to a substrate. It is also possible to use a proximity separation method in which the distance is set close to about 300 μm or less and the organic EL material is transferred by radiant energy such as laser (see, for example, Patent Document 5). Further, as described in Patent Document 4, a separation partition wall is formed on the interlayer insulating film in the non-pixel region in a direction perpendicular to the first transparent electrode, and the organic EL layer is formed and then peeled off. Thus, the light emitting unit 1 may be formed.

1.9 First metal thin film 124
The first metal thin film 124 is formed on the first organic EL layer 123. The first metal thin film 124 is effective in improving the contact with the transparent conductive film 312 in the intermediate electrode portion. The first metal thin film 124 is integrated with the first transparent conductive film 312 and functions as one of the carrier injection electrodes of the first light emitting unit.

2. Second Light Emitting Unit The second light emitting unit is provided with a second metal electrode 221, a second interlayer insulating film 222 defining a pixel region, a second organic EL layer 223, and a second metal thin film 224 in this order on a substrate 211. It has been. The second metal electrode 221 usually employs a material and a structure used for the metal electrode of the organic EL light emitting element. However, since the second metal electrode 221 is one of resonators for microcavity resonance, it may have higher reflectivity. It becomes important. In addition, the second metal electrode can inject carriers having the same polarity as the first transparent electrode. Further, the second metal electrode can be formed in a stripe shape formed in parallel with the first transparent electrode 121. The second interlayer insulating film 222 has the same configuration as the first interlayer insulating film 122, the second organic EL layer 223 has the same configuration as the first organic EL layer 123, and the second metal thin film 224 has the same configuration as the first metal thin film 124. Yes, it is formed in the same way.

3. Intermediate electrode part 3
The intermediate electrode unit 3 is located between the first light emitting unit 1 and the second light emitting unit 2 and electrically connects them in parallel.
The intermediate electrode unit 3 is formed by forming transparent conductive films 312 and 322 in a stripe pattern on both surfaces of a transparent substrate 311. As the transparent substrate 311, a transparent plastic film having a film thickness of about 50 to 500 μm and having a relatively high heat resistance is usually used. For example, PC (polycarbonate), PET (polyethylene terephthalate), and PES (polyethylene) are used. Ethersulfone), polyethylene naphthalate (PEN), polyolefin (PO 3), and the like can be suitably used. The materials used for the transparent substrate 311 are not limited to these materials, and a film based on a multilayer resin film may be used. The transparent conductive film is obtained, for example, by depositing ITO or IZO by sputtering. The film thickness is preferably 100 to 300 nm. A barrier layer may be formed between the transparent substrate 311 and the transparent conductive films 312 and 322. The barrier layer is obtained, for example, by depositing SiO _x or SiN _x by a CVD method. The film thickness is preferably 200 to 500 nm.

  Before the transparent conductive films 312 and 322 are formed in a stripe pattern on the film-like transparent substrate 311, through-holes 331 are formed in the transparent substrate 311 by laser beam irradiation, mechanical punching, or the like. When the transparent conductive films 312 and 322 are formed, the transparent conductive film material formed on the front and back surfaces of the transparent substrate 311 is filled in the through holes 331, and the transparent conductive films 312 and 322 are electrically connected to achieve the same polarity. It can be done. The place where the through-hole 331 is formed may be anywhere in the stripe pattern, but is preferably formed in a place that does not interfere with the pixel region.

  Under a dry nitrogen atmosphere in the glove box (both oxygen and moisture concentrations are 10 ppm or less), the intermediate electrode portion 3 formed as described above is disposed between the first light emitting portion 1 and the second light emitting portion 2, and these are arranged. An organic EL element can be obtained by bonding.

  At this time, the substrates are arranged so that the layers and the electrodes constitute the laminate shown in FIG. The intermediate light emitting portion 1 and the second light emitting portion 2 are arranged so that the first organic EL layer 123 and the second organic EL layer 223 are opposed to each of R, G, and B subpixels constituting the pixel. And put them together. The first and second organic EL layers 123 and 223 are electrically connected to the transparent conductive films 312 and 322 through the first and second metal thin films 124 and 224 provided in the first and second organic EL layers, respectively. Is done.

The present invention will be further described below using examples.
<Example 1>
In accordance with the manufacturing method described below, a first light emission having a pixel configuration of RGB subpixel size 0.148 mm × 0.704 mm and subpixel spacing 0.130 mm on a glass transparent substrate 111 of 500 mm × 500 mm × 0.50 mm. Part was formed.

  First, a resist resin containing a black pigment was applied by a spin coating method, and patterning was performed by a photolithographic method to form a black matrix 112 having a thickness of 2 μm, leaving an opening for forming a color filter.

  Blue filter material (Color Mosaic CB-7001, available from Fuji Film Co., Ltd.) is applied by spin coating, and then patterned by photolithography, 0.148mm x 0.704mm, blue with a spacing of 0.868mm A color filter was obtained.

  Next, a green filter material (color mosaic CG-7001, available from Fuji Film Co., Ltd.) is applied by a spin coating method, and then patterned by a photolithographic method, 0.148 mm × 0.704 mm, an interval of 0. An 868 mm green color filter was obtained.

  Next, after applying a red filter material (color mosaic CR-7001, available from Fuji Film Co., Ltd.) by a spin coating method, patterning is performed by a photolithographic method, 0.148 mm × 0.704 mm, an interval of 0. An 868 mm green color filter was obtained.

  Next, a UV curable resin (epoxy-modified acrylate) was applied on the color filter 113 thus obtained by spin coating, and irradiated with a high-pressure mercury lamp to form a flattened layer 114 having a thickness of 3 μm. . At this time, the pattern of the color filter 113 was not deformed, and the upper surface of the planarizing layer 114 was flat.

  Next, the substrate is transported to a vapor deposition apparatus, and a MgAg film having a thickness of 30 nm is laminated as a half mirror layer, and an IZO film having a thickness of 50 nm is laminated as a dielectric layer having a high refractive index (n = 2.2). Thus, the optical path adjustment layer 116 was formed in the region corresponding to the green pixel portion.

  Next, a color conversion layer 115 made of coumarin 6 and DCM-2 was produced in the red pixel region. That is, the color conversion layer 115 having a thickness of 200 nm was formed in the red pixel region by co-evaporation in which coumarin 6 and DCM-2 were heated in separate crucibles in the vapor deposition apparatus using a mask. At this time, the heating temperature of each crucible was controlled so that the deposition rate of coumarin 6 was 0.3 nm / s and the deposition rate of DCM-2 was 0.005 nm / s. The color conversion layer 115 of this example contained 2 mol% of DCM-2 based on the total number of molecules constituting the color conversion layer 115 (in this case, the number of moles of all dyes) (coumarin 6: DCM-2). The molar ratio is 49: 1).

Next, silicon nitride (SiN) having a film thickness of 400 nm is deposited using a plasma CVD method using monosilane (SiH ₄ ), ammonia (NH ₃ ), and nitrogen (N ₂ ) as source gases in a plasma CVD apparatus. A passivation layer 117 was formed. Here, the substrate temperature when depositing SiN was set to 100 ° C. or lower.

  A 200 nm thick ITO was vapor-deposited as a transparent electrode by sputtering. After applying a resist agent “OFRP-800” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) on ITO, patterning is performed by a photolithography method to form a stripe pattern having a width of 0.204 mm, an interval of 0.074 mm, and a film thickness of 200 nm. A first transparent electrode (cathode) 121 was obtained.

  Next, using a positive photoresist [WIX-2A] (trade name, manufactured by ZEON CORPORATION), an interlayer insulation having a thickness of 300 nm is formed so as to form an opening of 0.148 × 0.704 mm in a portion corresponding to the pixel region. The film 122 was formed between the stripe patterns constituting the first electrode 121. The angle of the end of the interlayer insulating film 122 with respect to the surface of the transparent substrate 111 is an acute angle.

Subsequent to the above steps, the substrate on which the interlayer insulating film 122 was formed was mounted in a resistance heating vapor deposition apparatus. Using a mask having an opening of a size of 0.148 × 0.704 mm corresponding to the sub-pixel region, the electron transport layer, the organic light emitting layer, and the hole transport layer are broken as the first organic EL layer 123 by breaking the vacuum. The film was formed in sequence without. During film formation, the internal pressure of the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. Electron transport layer and the Alq ₃ was 30nm laminated. The organic light emitting layer is composed of a host material 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi), blue dopant 4,4′-bis [2- {4- (N, N-diphenylamino) phenyl } Vinyl] biphenyl (DPAVBi) 5 wt% doped and laminated to 50 nm. As the hole transport layer, α-NPD was laminated to 120 nm. Thereafter, a metal thin film 124 made of Al having a thickness of 5 nm was formed by a similar mask film formation without breaking the vacuum. Thus, the 1st light emission part 1 was produced. The emission spectrum of the first light emitting part had peaks at wavelengths of 470 nm and 505 nm.

  Subsequently, a striped second metal electrode 221 is formed in parallel with the first transparent electrode 121 on the glass substrate 211 of 500 mm × 500 mm × 0.50 mm instead of the first transparent electrode 121. Except for, the second light emitting unit 2 was fabricated by the same procedure as the first light emitting unit 1.

  The second metal electrode 221 was formed as follows. First, Al was formed on the entire surface by sputtering. After applying a resist agent “OFRP-800” (trade name, manufactured by Tokyo Ohka Kogyo Co.) on Al, patterning is performed by a photolithography method to form a stripe pattern having a width of 0.204 mm, an interval of 0.074 mm, and a film thickness of 100 nm. A second metal electrode 221 was obtained.

The intermediate electrode part 3 was produced by the following method using a transparent substrate 311 made of a polyimide film of 500 mm × 500 mm × 0.50 mm.
SiN films were formed as barrier layers on both surfaces of the transparent substrate 311 by sputtering. Subsequently, through holes 331 were formed in the transparent substrate 311 and the SiN film between the pixel regions using a KrF excimer laser under the conditions of a laser spot diameter of 50 μm and a laser output of 100 mJ / pulse to 450 mJ / pulse.

  Next, ITO was formed on the entire surface of the transparent substrate 311 by sputtering. At this time, ITO was filled into the inside of the through-hole 331 that had been opened beforehand to form a contact, and both surfaces were electrically connected. Next, a YAG laser was swept on the ITO formed on both surfaces in a direction orthogonal to the stripe-shaped reflective electrode to separate the pixel area and the non-pixel area. In this way, transparent electroconductive films 312 and 322 each having a stripe pattern with a width of 0.204 mm, a gap of 0.048 mm, and a film thickness of 200 nm located in the RGB subpixels were obtained. In the present embodiment, the transparent conductive films 312 and 322 form part of the anodes of the first light emitting unit 1 and the second light emitting unit 2, respectively.

  The 1st light emission part 1, the 2nd light emission part 2, and the intermediate electrode part 3 which were obtained as mentioned above are introduce | transduced in a glove box. The substrates 111, 211, and 311 are arranged and overlapped so that the sub-pixel regions of the first light emitting unit 1 and the second light emitting unit 2 face each other and the cathode row and the anode row are orthogonal to each other. The transparent conductive films 312 and 322 were sandwiched between the first and second metal thin films 124 and 224, and sealed with a UV curing adhesive in a dry nitrogen atmosphere (both oxygen and moisture concentrations were 10 ppm or less).

<Example 2>
Except that the first and second organic EL layers 123 and 223 and the first and second metal thin films 124 and 224 are manufactured by the following procedure, and the first light emitting unit 1 and the second light emitting unit 2 are obtained. The procedure of Example 1 was repeated to obtain an organic EL device. The procedure of this embodiment will be described by taking the first light emitting unit as an example.

  A negative photoresist (ZPN1100, manufactured by Nippon Zeon Co., Ltd.) is applied to the transparent substrate 111 on which the first interlayer insulating film 122 is formed in the same manner as in Example 1 to a thickness of about 5 μm using a spin coater. After coating, it was pre-baked in a warm air circulation oven. The resist film is exposed using a photomask having a stripe-shaped opening pattern extending in a direction perpendicular to the direction in which the stripe-shaped partial electrodes constituting the first transparent electrode 121 extend, and post-baked in a hot air circulation oven Followed by development to obtain an electrically insulating separating partition. The obtained partition was composed of a plurality of stripe-shaped portions having a width of 30 μm and a pitch of 1016 μm.

Next, a first organic EL layer 123 was formed according to the same procedure as in Example 1 except that the mask was not used. Further, a first metal thin film 124 was formed according to the same procedure as in Example 1 except that no mask was used. Then, the cellophane tape prescribed | regulated to JISZ1522 was put on the partition, and only the metal thin film on a partition was peeled.
Next, a SiO film was formed on the entire surface of the transparent substrate 111 on which the first metal thin film 124 was formed. Further, the SiO film was etched by performing plasma etching using a SF ₆ / O ₂ / Ar mixed gas having a pressure of 100 Pa and a flow rate ratio of 2: 1: 1 and applying a power of 1.5 kW. Here, the first metal thin film functioned as an etch stop layer, and the protruding portion on the separation partition was removed.

<Comparative Example 1>
A light emitting unit having a pixel configuration with a subpixel size of 0.148 mm × 0.704 mm and a subpixel spacing of 0.130 mm was formed on a glass substrate 21 of 500 mm × 500 mm × 0.50 mm by the same procedure as in Example 2. . That is, in the same manner as in Example 1, the black matrix 22 was formed leaving the color filter forming openings, and the R, G, B color filters 23 were formed in the openings. Next, a planarization layer 24 was formed on the color filter 23 in the same manner as in Example 1, and a color conversion layer 25 was formed in the red pixel region. Next, a passivation layer 26 is formed in the same manner as in Example 1, and after forming a transparent electrode 27 thereon, an interlayer insulating film having a thickness of 300 nm is formed so as to form an opening in a portion corresponding to the pixel region. 28 was formed on the transparent electrode 27. As shown in FIG. 2, the green pixel region is not provided with an optical path adjustment layer, the light emitting portion 31 has a conventional structure using one separation partition 29, and an organic EL element in which the upper electrode 32 is made of Al is obtained. .

<Comparative example 2>
In Example 1, an organic EL device was obtained which was the same as Example 1 except that a green conversion layer made of coumarin 6 was produced in the green pixel region instead of the optical path adjustment layer.

(Evaluation)
When the characteristics of the element were evaluated, in Comparative Examples 1 and 2, the efficiency of R, G, B at an operating voltage of 6 V was 2.5, 7.5, 3.0 cd / A, 2.5, 8.0. 3.0 cd / A, but in the device of Example 1, the R, G, and B efficiencies were improved to 5, 10, and 6 cd / A at the same voltage, respectively. In the green pixel portion, the original spectrum having peaks at wavelengths of 470 nm and 505 nm is optically adjusted to form a microcavity resonance structure having a peak at wavelength of 520 nm. Therefore, the CIE chromaticity is not required without a green conversion layer. Gave (0.20, 0.71) green with good color purity. In Comparative Example 1, since CCM for green is not used, CIE chromaticity is (0.30, 0.60), and in Comparative Example 2, CIE chromaticity is (0.25, 0.70), and the color purity is not good. The respective NTSC ratios were 60% and 80%.

  According to the present invention, full-color display with high brightness and high color purity is possible, and the organic EL device according to the present invention can be applied to a wide range of screen displays such as portable terminals, industrial measuring instruments, and home televisions. Have.

It is a schematic diagram which shows the basic composition of the organic EL element of this invention. 6 is a schematic diagram showing a basic configuration of an organic EL element of Comparative Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st light emission part 2 2nd light emission part 3 Intermediate electrode part 100 Laminated body 111 Transparent substrate 112 Black matrix 113 Color filter 114 Flattening layer 115 Color conversion layer 116 Optical path adjustment layer 117 Passivation layer 121 1st transparent electrode 122 1st Interlayer insulating film 123 First organic EL layer 124 First metal thin film 211 Substrate 221 Second metal electrode 222 Second interlayer insulating film 223 Second organic EL layer 224 Second metal thin film 311 Transparent substrates 312 and 322 Transparent Conductive film 331 Through hole 21 Glass substrate 22 Black matrix 23 Color filter 24 Flattening layer 25 Color conversion layer 26 Passivation layer 27 Transparent electrode 28 Interlayer insulating film 29 Separating partition 31 Light emitting part 32 Upper electrode

Claims (4)

  An organic EL element having an organic EL light emitting portion provided with an organic light emitting layer that emits blue or blue-green light between opposing electrodes, wherein the organic light emitting portion is electrically connected in two stages in parallel. An organic EL element, wherein an optical path adjustment layer is formed in a green pixel region, and a color conversion layer is provided in a red pixel region.   2. The organic EL element according to claim 1, wherein the organic EL element is provided on a color filter of a substrate provided with a color filter on one surface.   The optical path adjustment layer provided in the green pixel region is provided on the light emitting side of the organic light emitting unit electrically connected in two stages in parallel, and is the outermost reflective electrode interface on the opposite side of the light emitting side of the organic light emitting unit. And an optical film thickness that modulates a peak wavelength of an emission spectrum of the organic EL light emitting unit to 500 to 550 nm by resonance between the light emitting side interface and the light exit side interface of the optical path adjusting layer. Item 3. The organic EL device according to Item 1 or 2.   The organic EL element according to claim 1, wherein the color conversion layer has a thickness of 50 to 2000 nm.

Images