JP2008130486A - Organic electroluminescent device and organic electroluminescent display having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent device having improved visibility under outdoor daylight, by restraining the reflection factor of the outdoor daylight, without lowering the luminous efficiency. <P>SOLUTION: In the organic electroluminescent element, an organic luminous layer is clamped by a first electrode, positioned at the side of a light extracting surface and a second electrode, positioned on a side opposite to the light extracting surface, and a polarizing plate is provided outside the first electrode. In the organic electroluminescent element, the second electrode has a half-transparent metal layer, a transparent conductive layer, and a reflection metal layer, successively starting from the side of the organic luminous layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention belongs to the technical field of organic EL elements and organic EL display devices which are light-emitting elements using organic compounds.

  An organic EL element (an organic light emitting element or an organic electroluminescent element) has a laminated structure in which an organic light emitting layer is sandwiched between a pair of electrodes. When a drive voltage is applied between the two electrodes, holes are injected from the anode and electrons are injected from the cathode, and the injected holes and electrons are recombined in the organic light emitting layer to emit light. Here, the organic light emitting layer includes organic layers such as an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer in addition to the light emitting layer.

  In general organic EL elements, in order to increase luminous efficiency, an electrode located on the light extraction surface side is often a transparent electrode, and an electrode located on the opposite side of the light extraction surface is often a reflective electrode made of metal.

  However, an organic EL element having a reflective electrode has a problem of a decrease in contrast due to reflection of external light.

  Therefore, in Patent Document 1, reflection of external light is prevented by providing a polarizing plate outside the light extraction surface side. As a specific example of the polarizing plate, there is a circularly polarizing plate composed of a combination of a linear polarizing plate and a quarter wavelength plate as disclosed in Patent Document 2.

  The circularly polarizing plate functions as follows. When the light entering the organic EL element enters the linear polarizing plate, only the linearly polarized light that matches the polarization axis of the linear polarizing plate is transmitted. This linearly polarizing plate becomes circularly polarized light by being influenced by the quarter wavelength plate. Therefore, the light that has passed through the circularly polarizing plate becomes circularly polarized light and enters the organic EL element, but becomes circularly polarized light having a reverse rotation direction when reflected by the reflective electrode. The reflected light becomes circularly polarized light opposite to the incident light and enters the quarter-wave plate again. And since the reflected light converted into the linearly polarized light by the quarter wavelength plate does not coincide with the polarization axis of the linearly polarizing plate, it is absorbed by the linearly polarizing plate. For this reason, the contrast of the display image under external light is improved.

  However, the organic EL element having a circularly polarizing plate has a problem that the light emission efficiency is lowered because about half of the light emitted from the light emitting layer is absorbed by the circularly polarizing plate.

  Therefore, in Patent Document 3, the light emission efficiency is improved by varying the transmittance and polarization efficiency of the circularly polarizing plate for each specific wavelength band.

Japanese Patent No. 2761453 Japanese Patent Laid-Open No. 9-127858 JP 2005-332815 A

  However, since the circularly polarizing plate is configured to particularly prevent external light reflection around the wavelength 555 nm having high visibility, the reflectance increases as the distance from the wavelength 555 nm increases. Since visible light is generally in the wavelength band around 380 nm to 780 nm, it is difficult to reduce the reflectance of the entire visible light only by using a circularly polarizing plate, and the blue wavelength band is around 450 nm, or the red wavelength band. The reflectance at around 600 nm is relatively high. Therefore, when external light is incident on the organic EL element having a circularly polarizing plate, there is a problem that it is bluish or reddish.

In particular, in the case of a circularly polarizing plate with increased transmittance in a specific wavelength band, the reflectance of the specific wavelength band also increases, so there is a problem that the contrast is lowered and the color of the specific wavelength band appears. In order to prevent this, there is a method of applying an AR coating to the surface of the circularly polarizing plate. However, since the AR coating is designed to suppress the reflectance at a wavelength of 555 nm with high visibility, it has the same problem as described above. .

  In order to solve such problems, the present invention provides an organic EL element and an organic EL display device having a polarizing plate, and reduces the reflectance of outside light without reducing the luminous efficiency as much as possible. The purpose is to improve visibility.

As means for solving the problems of the background art, the organic EL element according to the invention described in claim 1 is:
An organic EL layer in which an organic light emitting layer is sandwiched between a first electrode located on the light extraction surface side and a second electrode located on the opposite side of the light extraction surface, and a polarizing plate is provided outside the first electrode In the element
The second electrode is characterized by having a semi-transmissive metal layer, a transparent conductive layer, and a reflective metal layer in order from the organic light emitting layer side.

  According to the present invention, it is possible to reduce the external light reflectance in a wavelength band that cannot be prevented by the polarizing plate alone. Accordingly, it is possible to provide an organic EL element and an organic EL display device that can obtain good visibility even under external light.

  An organic EL element that is sandwiched between a first electrode located on the light extraction surface side and a second electrode located on the opposite side of the light extraction surface, and in which a polarizing plate is provided outside the first electrode, and the same An organic EL display device having an organic EL element.

  The organic EL element according to the present invention and the organic EL display device having the organic EL element are arranged in order from the organic light emitting layer side in order to reduce the external light reflectance in the wavelength band that cannot be prevented by the polarizing plate alone. It consists of three layers, a semi-transmissive metal layer, a transparent conductive layer, and a reflective metal layer. The film thicknesses of the semi-transmissive metal layer, the transparent conductive layer, and the reflective metal layer are adjusted so that the light reflected by the semi-transmissive metal layer and the light reflected by the reflective metal layer cancel each other. Therefore, incident light in a wavelength band that cannot be prevented only by the polarizing plate is attenuated in the second electrode, and the external light reflectance can be satisfactorily reduced.

  In particular, when the optical distance between the reflective metal layer and the semi-transmissive metal layer of the second electrode is set so as to satisfy <Equation 1>, incident light can be attenuated more satisfactorily. Specifically, it is ideal that the phases of the two reflected lights are reversed and the intensities are equal at the wavelength λ of the light to be quenched. The intensity is adjusted by the film thickness of the semi-transmissive metal layer, and the phase is adjusted by the optical distance between the reflective metal layer and the semi-transmissive metal layer. Therefore, it is important to appropriately set the film thickness and optical distance of the semi-transmissive metal layer.

（ｍは１以上の整数）

(M is an integer of 1 or more)

  However, the sum of the phase shift of the reflected light at the interface between the semi-transmissive metal layer and the transparent conductive layer and the phase shift of the reflected light at the interface between the metal reflective layer and the transparent conductive layer is Φ, and the reflective metal layer and the semi-transmissive layer Let L be the optical distance to the metal layer and λ be the wavelength of the light to be quenched.

<Embodiment 1>
An embodiment of an organic EL device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic partial enlarged sectional view of an organic EL device according to the present invention. The organic EL element described here is a bottom emission type in which light is extracted from the TFT substrate side.

  In the organic EL element shown in FIG. 1, a planarizing film (not shown) provided with a contact hole is formed on a substrate 1 on which a TFT drive circuit is formed. On this flattened film, a transparent anode electrode 2 as an anode (first electrode), a hole injection layer 3 as an organic light emitting layer, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, an electron injection layer 7, a cathode ( A reflective cathode electrode 11 is sequentially formed as a second electrode. A polarizing plate 14 is provided on the surface of the substrate 1 on the light extraction surface side (that is, outside the first electrode). The polarizing plate 14 includes a linear polarizing plate 12 and a quarter wavelength plate 13. It has a multilayer structure (circularly polarizing plate).

  This organic EL element is characterized in that the reflective cathode electrode 11 has a structure in which a semi-transmissive metal layer 8, a transparent conductive layer 9, and a metal layer 10 are sequentially laminated.

Here, in order to reduce the reflectance of light having a wavelength of 400 nm, the configuration of the reflective cathode electrode 11 is
Semi-transmissive metal layer 8; Ag 45 nm
Transparent conductive layer 9; ITO 60nm
Metal layer 10; Al 100 nm
And The sum of the reflected light phase shift between the semi-transmissive metal layer 8 and the transparent conductive layer 9 and the reflected light phase shift between the transparent conductive layer 9 and the metal layer 10 is approximately 4π / 5. Therefore, L = 120 in order to establish Equation 1 at m = 1. The optical distance L is the product of the refractive index and the film thickness of the transparent conductive layer 9. Since the refractive index of the transparent conductive layer 9 at a wavelength of 400 nm is around 2 to 2.1, the film thickness was set to 60 nm. The calculation of the phase shift and the reflectance is obtained from the optical calculation using the Fresnel coefficient.

  FIG. 2 shows the reflectance of light incident on the reflective cathode electrode 11 from the organic light emitting layer (n = 1.7) in the organic EL element having the above configuration. While the reflectance at a wavelength of 400 nm is as low as 47%, the reflectance in the wavelength band of 450 to 650 nm corresponding to the emission wavelength of the organic EL element is as high as 85% or more, and a highly efficient organic EL It turns out that it is an element.

  In addition, the organic EL material known conventionally can be used for the material used for each layer of an organic light emitting layer.

  As the material of the transparent anode electrode 2, a material having a large work function is suitable for efficiently injecting holes, and for example, a transparent conductive material such as ITO or IZO is used.

  As a material of the reflective cathode electrode 11, a material having a small work function is preferable in order to efficiently inject electrons. Specific examples of the material used for the metal layer 8 include metals such as aluminum, calcium, magnesium, silver, and gold, or alloys containing these metals.

  Regarding the film forming method, conventionally known methods are used for both the organic material and the electrode material, and there is no particular limitation.

<Comparative Example 1>
As Comparative Example 1, an organic EL element similar to that of Embodiment 1 is considered except that the reflective cathode electrode is formed of Ag having a thickness of 100 nm.

  FIG. 2 shows the reflectance of light incident on Ag, which is a reflective cathode electrode, from the organic light emitting layer (n = 1.7) in Comparative Example 1, but the reflectance in the wavelength band of 400 to 500 nm is the above embodiment. It can be seen that it is higher than 1.

  FIG. 3 shows a comparison of specular reflection characteristics at an incident angle of 45 degrees in the organic EL elements of Embodiment 1 and Comparative Example 1. Since Embodiment 1 has a smaller reflectance in the wavelength band of 400 to 500 nm than Comparative Example 1, the average reflectance of the entire visible light is also smaller. Therefore, compared with the organic EL element of Comparative Example 1, the organic EL element of Embodiment 1 can obtain good visibility even under external light.

<Embodiment 2>
FIG. 4 shows a schematic partial enlarged sectional view of the organic EL display device according to the present invention. The organic EL display device described here is a top emission type in which light is extracted from the glass plate (sealing member) side.

  The organic EL display device illustrated in FIG. 4 includes organic EL elements 212R, 212G, and 212B that emit red (R), green (G), and blue (B) emission colors. In the present embodiment, the organic EL elements 212R, 212G, and 212B of the respective colors are configured by the organic EL elements according to the present invention. However, the organic EL element 212B that exhibits at least a blue emission color is the organic EL element according to the present invention. What is necessary is just to comprise.

  More specifically, a planarization film (not shown) provided with contact holes is formed on the substrate 21 on which the TFT drive circuit is formed. On this flattened film, a reflective anode 26 as an anode (second electrode), a hole transport layer 27 as an organic light emitting layer, a light emitting layer 28R (28G, 28B), an electron transport layer 29, an electron injection layer 210, a cathode ( A transparent cathode electrode 211 and a protective layer 213 are formed as a first electrode). A blue transmissive polarizing plate 217 is formed outside the transparent cathode electrode 211. The blue transmissive polarizing plate 217 has a multilayer structure (circular polarizing plate) including a quarter-wave plate 215 and a linear polarizing plate 216. Has been. Incidentally, a blue transmissive circularly polarizing plate is one having a higher transmittance in the blue wavelength region than a normal circularly polarizing plate.

  This organic EL display device is characterized in that the reflective anode 26 has a structure in which a metal layer 22, a transparent conductive layer 23, a semi-transmissive metal layer 24, and a transparent conductive layer 25 are sequentially laminated. In addition, the reflective anode electrode 26 of this embodiment forms the transparent conductive layer 25 from a viewpoint of hole injection property.

Here, the configuration of the reflective anode electrode 26 is
Metal layer 22; Al 100 nm
Transparent conductive layer 23; ITO 60nm
Semi-transmissive metal layer 24; Ag 40 nm
Transparent conductive layer 25; IZO 20 nm
And At this time, IZO is used as the anode material in contact with the organic light emitting layer in order to increase the hole injection efficiency. The film thickness of the transparent conductive layer 23 was determined in the same manner as in Example 1.

  FIG. 5 shows the reflectance of light incident on the reflective anode electrode 26 from the organic light emitting layer (n = 1.7) in the organic EL element having the above configuration. While the reflectance at a wavelength of 400 nm is as low as 20%, the reflectance at a wavelength band of 450 to 650 nm is 75% or more, which indicates that the organic EL display device is highly efficient.

<Comparative example 2>
As Comparative Example 2, an organic EL display device in which the reflective anode electrode is made of Ag having a thickness of 100 nm and IZO having a thickness of 20 nm, and the organic light emitting layer, the transparent cathode electrode, and the protective layer are the same as in the second embodiment is considered.

  FIG. 5 shows the reflectance of light incident on the reflective anode electrode from the organic light emitting layer (n = 1.7) in Comparative Example 2, but the reflectance in the wavelength band of 400 to 500 nm is higher than that in the second embodiment. I understand that it is expensive.

  FIG. 6 shows a comparison of specular reflection characteristics at an incident angle of 45 degrees in the organic EL display device of Embodiment 2 and Comparative Example 2. In Embodiment 2, since a blue transmissive circularly polarizing plate having a high transmittance in the blue wavelength band is used, reflection in the blue wavelength band is larger than that of a normal circularly polarizing plate. The CIE chromaticity coordinates of the reflected light at this time were (0.24, 0.24) in the second embodiment and (0.23, 0.22) in the second comparative example. That is, in Embodiment 2, it turns out that the blue color of the reflected light at the time of using a blue transmissive circularly-polarizing plate is improved.

  Moreover, since the reflectance in the wavelength band of 400 to 500 nm is smaller in the second embodiment than in the second comparative example, the luminous reflectance (Y stimulus value) is also smaller. Therefore, the organic EL display device of Embodiment 2 can obtain better visibility even under external light than the organic EL display device of Comparative Example 2.

<Embodiment 3>
As Embodiment 3 of the present invention, an organic EL display device having the same configuration as that of Embodiment 2 but having a different thickness of each layer in the reflective anode electrode is shown (not shown).

  As in the second embodiment, the reflective anode 26 located on the side opposite to the light extraction surface is configured by sequentially laminating the metal layer 22, the transparent conductive layer 23, the semi-transmissive metal layer 24, and the transparent conductive layer 25. ing.

Here, the film thickness of each layer is
Metal layer 22; Al 100 nm
Transparent conductive layer 23; ITO 70nm
Transflective metal layer 24; Ag 15 nm
And In order to suppress the reflectance in the blue wavelength band, the wavelength around 450 nm is set as the extinction wavelength. The sum of the reflected light phase shift between the semi-transmissive metal layer 24 and the transparent conductive layer 23 and the reflected light phase shift between the transparent conductive layer 23 and the metal layer 22 is approximately 11π / 15. Therefore, L = 142.5 in order to establish Equation 1 at m = 1. Since the refractive index of the transparent conductive layer 23 at a wavelength of 450 nm is around 2 to 2.1, the film thickness was set to 70 nm.

  FIG. 7 shows the reflectance of light incident on the reflective cathode electrode 11 from the organic light emitting layer (n = 1.7) in the organic EL display device having the above configuration. Since Embodiment 3 is configured to completely eliminate the blue color when using a blue transmissive circularly polarizing plate, the reflectance in the blue wavelength band is suppressed. Compared with the first and second embodiments, this embodiment has a wide band in a region with low reflectivity. This is because the transmissivity of the semi-transmissive metal layer is low because the thickness of the semi-transmissive metal layer is thin.

  FIG. 8 shows a comparison of regular reflection characteristics at an incident angle of 45 degrees in the organic EL display device of Embodiment 3 and Comparative Example 2. The CIE chromaticity coordinates of the reflected light at this time were (0.33, 0.35) in Embodiment 3 and (0.23, 0.22) in Comparative Example 2. Therefore, in Embodiment 3, the blueness of the reflected light when the blue transmissive circularly polarizing plate is used is completely eliminated, and the luminous reflectance (Y stimulus value) is also smaller than that of Comparative Example 2. Therefore, the organic EL display device of Embodiment 3 can obtain good visibility even under external light.

  As described above, the present invention has been described with reference to the embodiments, and the effects of the present invention have been shown while giving comparative examples. However, the present invention is not limited to the above embodiment. In the above embodiment, the light extraction surface side electrode is a transparent electrode, but a metal thin film may be used as the light extraction surface side electrode.

  Further, the present invention can obtain the same effect even in a configuration in which a plurality of metal layers and a plurality of transparent conductive layers are sequentially laminated. The polarizing plate has been described using a circularly polarizing plate composed of a quarter-wave plate and a linear polarizing plate, but the polarizing plate is not limited to a combination of a quarter-wave plate and a linear polarizing plate. Actually, in the second and third embodiments, a blue transmissive circularly polarizing plate is used, which has a higher transmittance in a blue wavelength band of 400 to 500 nm than a normal circularly polarizing plate. However, a circularly polarizing plate having a maximum transmittance of 50% or more in the wavelength band of 400 to 500 nm and a minimum transmittance of less than 50% in the wavelength band of 500 to 600 nm was defined as a blue transmitting circularly polarizing plate. Although the transmittance characteristics are shown in FIG. 9, the maximum value of the transmittance in the wavelength band of 400 to 500 nm of the blue transmissive circularly polarizing plate is 50% or more, but the normal circularly polarizing plate is less than 50%.

  Furthermore, the present invention can be implemented for a multi-photon configuration in which a plurality of organic EL elements are stacked or a multi-step stacked configuration.

  Hereinafter, the present invention will be described specifically by way of examples.

<Example 1>
A bottom emission type blue organic EL element similar to that of Embodiment 1 was prepared by the following method.

  A planarizing film (not shown) provided with contact holes was formed on the substrate 1 on which the TFT drive circuit was formed. On this, IZO was formed as a transparent anode electrode 2 with a film thickness of 60 nm by sputtering and patterned. Next, an element separation film (not shown) was formed from an acrylic resin to prepare a substrate with an anode. This was ultrasonically washed with isopropyl alcohol (IPA), then boiled and dried.

  Further, after UV / ozone cleaning, an organic compound was formed by vacuum deposition.

That is, as the hole injection layer 3, Cu-coordinated phthalocyanine (hereinafter referred to as CuPc) was formed to a thickness of 10 nm. The degree of vacuum at this time was 1 × 10 ⁻⁴ Pa, and the deposition rate was 0.2 nm / sec.

As the hole transport layer 4, α-NPD was formed to a thickness of 20 nm. The degree of vacuum at this time was 1 × 10 ⁻⁴ Pa, and the deposition rate was 0.2 nm / sec.

The light emitting layer 5 was formed with a film thickness of 20 nm by co-evaporating Balq and a light emitting compound Perylene as a host (weight ratio 90:10). The degree of vacuum at this time was 1 × 10 ⁻⁴ Pa, and the deposition rate was 0.2 nm / sec.

As the electron transport layer 6, bathophenanthroline (Bphen) was formed with a film thickness of 10 nm by a vacuum deposition method. The degree of vacuum during vapor deposition was 1 × 10 ⁻⁴ Pa, and the film formation rate was 0.2 nm / sec.

As the electron injection layer 7, Bphen and Cs ₂ CO ₃ were co-evaporated (weight ratio 90:10) to form a film thickness of 30 nm. The degree of vacuum during vapor deposition was 3 × 10 ⁻⁴ Pa, and the film formation rate was 0.2 nm / sec.

As the semi-transmissive metal layer 8, silver (Ag) was formed with a film thickness of 45 nm. The degree of vacuum during vapor deposition was 1 × 10 ⁻⁴ Pa, and the film formation rate was 0.2 nm / sec. And it moved to the sputtering device without breaking the vacuum, and an ITO transparent electrode with a film thickness of 60 nm was formed as the transparent conductive layer 9. Further, as the metal layer 10, Al was formed with a film thickness of 100 nm to form a reflective canode electrode 11.

  After sealing a metal can (not shown), a circularly polarizing plate 14 was attached to the surface of the substrate 1 on the light extraction surface side to obtain a desired organic EL element.

<Example 2>
An organic EL display device having a top emission type RGB organic EL element similar to that of Embodiment 2 was produced by the method described below.

  A planarizing film (not shown) provided with contact holes was formed on the substrate 21 on which the TFT drive circuit was formed.

  On this, Al was formed with a film thickness of 100 nm by sputtering as the metal layer 22 and patterned. As the transparent conductive layer 23, ITO was formed by sputtering to a thickness of 50 nm and patterned. As the semi-transmissive metal layer 24, Ag is formed with a film thickness of 35 nm by a sputtering method, and further, as the transparent conductive layer 25, IZO is formed with a film thickness of 20 nm by a sputtering method and patterned, so that a reflective anode electrode is formed. 26 was formed.

  Next, an element separation film (not shown) was formed from an acrylic resin to prepare a substrate with an anode. This was ultrasonically washed with isopropyl alcohol (IPA), then boiled and dried.

  Further, after UV / ozone cleaning, an organic compound was formed by vacuum deposition.

That is, α-NPD was formed as a common hole transport layer 27 with a film thickness of 25 nm. The degree of vacuum at this time was 1 × 10 ⁻⁴ Pa, and the deposition rate was 0.2 nm / sec.

  As the light emitting layer 28, RGB light emitting layers were formed using a shadow mask.

As the R light emitting layer 28R, Alq3 as a host,
Luminescent compound DCM [4- (dicyanomethylene) -2-methyl-6 (p-dimethylaminostyryl) -4H-pyran],
Were co-evaporated (weight ratio 99: 1) to form a film with a thickness of 50 nm.

  The G light-emitting layer 28G was formed to have a film thickness of 35 nm by co-evaporating Alq3 as a host and the light-emitting compound coumarin 6 (weight ratio 99: 1).

  The B light-emitting layer 28B was formed to a thickness of 20 nm by co-evaporating Balq and a light-emitting compound Perylene as a host (weight ratio 90:10).

The degree of vacuum at this time was 1 × 10 ⁻⁴ Pa, and the deposition rate was 0.2 nm / sec.

As the common electron transport layer 29, bathophenanthroline (Bphen) was formed to a thickness of 10 nm by a vacuum deposition method. The degree of vacuum during vapor deposition was 1 × 10 ⁻⁴ Pa, and the film formation rate was 0.2 nm / sec.

As a common electron injection layer 210, Bphen and Cs ₂ CO ₃ were co-evaporated (weight ratio 90:10) and formed to a thickness of 20 nm. The degree of vacuum during vapor deposition was 3 × 10 ⁻⁴ Pa, and the film formation rate was 0.2 nm / sec.

  And it moved to the sputtering device without breaking the vacuum, and IZO was formed with a film thickness of 60 nm as the transparent cathode electrode 211. Further, as the protective film 213, silicon nitride oxide was formed with a thickness of 700 nm.

  Subsequently, the substrate formed up to the protective layer 213 is taken out from the sputtering apparatus, an acrylic resin (not shown) having a thickness of 500 μm is formed on the protective layer 213, and a glass plate 214 having a thickness of 700 μm is further formed on the acrylic resin layer. Were pasted together.

  Then, a blue transmissive circularly polarizing plate 217 was attached on the glass plate 214 to obtain a desired organic EL display device.

<Example 3>
An organic EL display device having an RGB organic EL element of the top emission type substantially the same as that of Embodiment 3 was produced.

  Since the present embodiment has the same structure as that of the second embodiment, the creation procedure is the same. However, the reflective anode 26 was formed with a thickness of 70 nm as the transparent conductive layer 23 and with a thickness of 15 nm as the semi-transmissive metal layer 24. Except that the film thicknesses of the transparent conductive layer 23 and the semi-transmissive metal layer 24 are different, the production method, material, and film thickness are the same as those in Example 2 to obtain a desired organic EL display device.

It is a schematic sectional drawing of the organic EL element which concerns on this invention. It is a comparison figure of the electrode reflectance of Embodiment 1 and comparative example 1. It is a comparison figure of the regular reflection characteristic of Embodiment 1 and the comparative example 1. FIG. 1 is a schematic cross-sectional view of an organic EL display device according to the present invention. It is a comparison figure of the electrode reflectance of Embodiment 2 and comparative example 2. It is a comparison figure of the regular reflection characteristic of Embodiment 2 and the comparative example 2. FIG. It is a comparison figure of the electrode reflectance of Embodiment 3 and comparative example 2. It is a comparison figure of the regular reflection characteristic of Embodiment 3 and the comparative example 2. FIG. It is a comparison figure of the transmittance | permeability of a circularly-polarizing plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Transparent anode electrode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Electron injection layer 8 Transflective metal layer 9 Transparent conductive layer 10 Metal layer 11 Reflective cathode electrode 12 Linearly polarizing plate 13 1 / Four-wavelength plate 14 Circularly polarizing plate 21 Substrate 22 Metal layer 23 Transparent conductive layer 24 Transflective metal layer 25 Transparent conductive layer 26 Reflective anode electrode 27 Hole transport layer 28 Light emitting layer 29 Electron transport layer 210 Electron injection layer 211 Transparent cathode electrode 212 Organic EL element 213 Protective layer 214 Glass plate

Claims (5)

An organic EL layer in which an organic light emitting layer is sandwiched between a first electrode located on the light extraction surface side and a second electrode located on the opposite side of the light extraction surface, and a polarizing plate is provided outside the first electrode In the element
The second electrode is configured to include a semi-transmissive metal layer, a transparent conductive layer, and a reflective metal layer in order from the organic light emitting layer side. The optical distance between the reflective metal layer and the transflective metal layer is

(M is an integer of 1 or more)
(However, the sum of the phase shift of the reflected light at the interface between the semitransparent metal layer and the transparent conductive layer and the phase shift of the reflected light at the interface between the metal reflective layer and the transparent conductive layer is Φ, (The optical distance between the transparent metal layer is L, and the wavelength of light to be quenched is λ.)
The organic EL element according to claim 1, wherein the organic EL element is set so as to satisfy.   The organic EL element according to claim 1, wherein the polarizing plate has a multilayer structure.   The organic EL element according to claim 3, wherein the polarizing plate comprises a ¼ wavelength plate and a linear polarizing plate. In an organic EL display device having a plurality of organic EL elements and exhibiting two or more emission colors,
The organic EL element exhibiting the selected emission color is formed by sandwiching an organic light emitting layer between a first electrode located on the light extraction surface side and a second electrode located on the opposite side of the light extraction surface. A polarizing plate is provided outside the electrode;
The organic EL display device, wherein the second electrode of the organic EL element includes a semi-transmissive metal layer, a transparent conductive layer, and a reflective metal layer in order from the organic light emitting layer side.

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