WO2016072246A1

WO2016072246A1 - Organic electroluminescence element

Info

Publication number: WO2016072246A1
Application number: PCT/JP2015/079406
Authority: WO
Inventors: 宏石代; 敦今村; 中山　知是
Original assignee: コニカミノルタ株式会社
Priority date: 2014-11-04
Filing date: 2015-10-19
Publication date: 2016-05-12
Also published as: JPWO2016072246A1

Abstract

The present invention addresses the problem of providing an organic electroluminescence element which is of a two-side emission type and is transparent when not emitting light but emits light at a uniform brightness and chromaticity from both sides when emitting light, and with which the light emission color can be freely altered. This organic electroluminescence element has, layered in the following order, at least a light-transmitting substrate, a light-transmitting first electrode, an odd number of three or more light-emitting units, a plurality of light-transmitting intermediate electrodes arranged between the light-emitting units, a light-transmitting second electrode, and a light-transmitting sealing substrate, and is sealed by the light-transmitting sealing substrate. The organic electroluminescence element is characterized in that the odd number of three or more light-emitting units include the use of at least two different types of light-emitting unit selected from light-emitting units having light emission colors of blue, green, red, or a mixture thereof, and light-emitting units of different light emission colors are each arranged at positions of symmetry with respect to a light-emitting unit that is arranged in the center.

Description

Organic electroluminescence device

The present invention relates to an organic electroluminescence element. More specifically, it is a double-sided light-emitting organic electroluminescence element that is transparent when not emitting light, emits light with uniform brightness and chromaticity from both sides when emitting light, and freely changes the emission color. The present invention relates to an organic electroluminescence device capable of producing

At present, a light emitting element using electroluminescence (EL) of an organic material is attracting attention as a thin light emitting device.

A so-called organic electroluminescence element (hereinafter also referred to as an organic EL element) is a thin-film completely solid element that can emit light at a low voltage of several V to several tens V, and has high brightness, high luminous efficiency, thin thickness, It has many excellent features such as light weight. For this reason, it has been attracting attention in recent years as surface light emitters such as backlights for various displays, display boards such as signboards and emergency lights, and illumination light sources.

Such an organic EL element has a structure in which a light emitting layer made of an organic material (also referred to as a light emitting unit in the present application) is disposed between two opposing electrodes, and the emitted light generated in the light emitting layer passes through the electrode. Permeated and taken out to the outside. For this reason, at least one of the two electrodes is configured as a transparent electrode, and emitted light is extracted from the transparent electrode side.

On the other hand, the demand for a substantially transparent organic EL element capable of emitting light on both sides is increasing due to its high design. In addition, a flexible organic EL element that can emit light on both sides and can freely change the emission color is extremely high in design and lightweight, and therefore has a wide range of applications as an advertising medium or a lighting device.

As an organic EL element capable of emitting light on both sides, in Patent Document 1, a reflective conductive intermediate electrode is arranged in the center, and a light emitting layer and an electrode are laminated on both sides to enable double-sided light emission. Therefore, when not emitting light, it is not transparent and uses are limited.

Patent Document 2 discloses an organic EL element in which a plurality of light emitting layers, an intermediate electrode layer, and a charge generation layer are laminated between an anode (anode) layer and a cathode (cathode) layer, and the light emitting layer is blue (B), green ( G), red (R) light is emitted, and the intermediate electrode layer is a transparent electrode. Therefore, the organic EL element can emit light of various colors from both sides of the element and is transparent when not emitting light. It becomes. However, since an ITO film or an aluminum film is used as the material for the anode (anode) and the cathode (cathode), and an aluminum film or a magnesium-silver film is used as the intermediate electrode, the transparency is poor. In addition, although it is possible to emit light on both sides, the layers that emit light of different colors such as blue, green, red, etc. are stacked, so when actually observed from both sides, there are differences in color tone and brightness, and both sides emit light. Inferior uniformity of light when the light is emitted, and the emission color cannot be freely changed.

In Patent Document 3, by adjusting the layer thickness of the transparent conductive film provided on the cathode (cathode) side and the layer thickness of the cathode (cathode), both the light emission on the upper surface and the light emission on the lower surface are uniform in color tone, In addition, the object is to obtain a high-quality image display, but since there is a gap inside the element, reflection occurs at the interface between the electrode and the sealing space, and the lower electrode side emits light more strongly, resulting in a uniform emission. There is a problem that double-sided light emission cannot be performed and a problem that the viewing angle dependency of chromaticity is large.

Therefore, at present, an organic electroluminescence element that is transparent when not emitting light, emits light with uniform brightness and chromaticity from both sides when emitting light, and can freely change the emission color has not been obtained.

JP 2009-266520 A JP 2009-252458 A JP 2004-265691 A

The present invention has been made in view of the above-mentioned problems and situations, and the problem to be solved is that it is transparent when not emitting light, emits light with uniform brightness and chromaticity from both sides when emitting light, and freely emits color. It is to provide an organic electroluminescence device capable of changing the above.

In order to solve the above problems, the present inventor, in the process of examining the cause of the above problems, at least a translucent substrate, a translucent first electrode, an odd number of three or more light emitting units, and between the light emitting units. A plurality of light-transmitting intermediate electrodes, a light-transmitting second electrode, and a light-transmitting sealing substrate that are disposed are stacked in this order, and are organic electroluminescence elements sealed by the light-transmitting sealing substrate, It has been found that the above-mentioned problems can be solved by an organic electroluminescence element in which the odd number of light emitting units of 3 or more are light emitting units having a light emitting property selected from specific light emitting colors and are laminated in a specific arrangement. .

That is, the above-mentioned problem according to the present invention is solved by the following means.

1. At least a translucent substrate, a translucent first electrode, an odd number of three or more light emitting units, a plurality of translucent intermediate electrodes arranged between the light emitting units, a translucent second electrode, and a translucent seal An organic electroluminescence device in which substrates are stacked in this order and sealed by the translucent sealing substrate, wherein the odd number of the three or more light emitting units are blue, green and red, or a mixture thereof An organic electro that uses at least two types of light emitting units selected from light emitting units having a light emitting color, and has light emitting units of different light emitting colors arranged at symmetrical positions with respect to the light emitting unit arranged in the center. Luminescence element.

2. The light emitting center inside the light emitting units at the symmetrical positions of the odd number of light emitting units of 3 or more is respectively equidistant from the light emitting centers of the light emitting units arranged at the center. The organic electroluminescent element of description.

3. 3. The organic electroluminescent element according to claim 1 or 2, wherein the translucent substrate and the translucent sealing substrate are both flexible substrates and are made of the same material. .

4. Any one of the first to third aspects, wherein the polarities of the plurality of translucent intermediate electrodes are positive and negative repeating order from the translucent substrate side, or negative and positive repeating order The organic electroluminescent element according to claim 1.

5. The first to fourth items, wherein the translucent first electrode, the translucent intermediate electrode, and the translucent second electrode are all transparent electrodes mainly composed of silver. The organic electroluminescent element as described in any one.

By the above means of the present invention, there is provided an organic electroluminescence device which is transparent when not emitting light, emits light with uniform brightness and chromaticity from both sides when emitting light, and can freely change the emission color. it can.

The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

The organic electroluminescence element of the present invention includes at least a light transmissive substrate, a light transmissive first electrode, an odd number of three or more light emitting units, a plurality of light transmissive intermediate electrodes arranged between the light emitting units, and a light transmissive property. The second electrode and the light-transmitting sealing substrate are stacked in this order, the element is sealed by the light-transmitting sealing substrate, and the odd number of the three or more light emitting units are blue, green and red, or they By using at least two types of light emitting units selected from light emitting units having a mixed light emitting color, and arranging light emitting units having different light emitting colors at symmetrical positions with respect to the light emitting units arranged in the center, It is transparent when not emitting light, and emits light with uniform brightness and chromaticity from both sides when emitting light, and is appropriately applied to the translucent first electrode, translucent second electrode, and translucent intermediate electrode. , It is possible to provide an organic electroluminescent device can be changed freely emission color.

Conventional double-sided light-emitting organic EL elements, as disclosed in Patent Document 2, generally have a structure in which layers for emitting blue, green, and red light are stacked as a light-emitting unit. Then, although the emission color can be changed and both sides can emit light, since the layers emitting light of different colors such as blue, green, red, etc. are laminated, actually observing the organic EL element from both sides, Since the layer order of the layers emitting different colors is different, the color tone and brightness of the observed emitted light are different, and the chromaticity and brightness uniformity of the light emitted from both sides are inferior.

A light emitting unit according to the present invention uses at least two types of light emitting units selected from light emitting units having blue, green and red light emitting colors, and an odd number of three or more light emitting units, and is arranged in the center. By arranging light emitting units with different emission colors at symmetrical positions, the order of the layers of the units emitting different colors is the same when the organic EL element is observed from both sides. It is speculated that the uniformity of the chromaticity and brightness of the light to be improved and an organic EL element that can be easily adjusted when changing the emission color can be obtained.

In particular, when the light emission centers inside the light emission units at the symmetrical positions of the odd number of the light emission units of 3 or more are equidistant from the light emission centers of the light emission units arranged in the center, it contributes to uniformity. Inferred.

Moreover, the translucent substrate and the translucent sealing substrate are both flexible substrates and are formed of the same material, so that the translucency of the substrate and the refractive index inside the element are the same, Regardless of the design of the light-emitting unit, it is assumed that uniform light-emitting characteristics can be obtained on both sides.

Further, when the translucent first electrode, the plurality of translucent intermediate electrodes, and the translucent second electrode are electrodes mainly composed of silver, indium oxide, which is conventionally known as a transparent electrode, Compared to tin (SnO ₂ —In ₂ O ₃ : Indium Tin Oxide: ITO) electrode, it can be adjusted to a thin film that does not cause specular reflection at the metal electrode, so it is necessary to consider the loss of light due to the specular reflection. It is considered that the light emission characteristics on both sides are substantially the same, and the transparency of the entire device is improved.

In addition, the organic EL element of the present invention is preferably solid-sealed (also referred to as laminate sealing) by the translucent sealing substrate, and thus has a hollow portion applied to a general organic EL element. It is presumed that there is almost no reflection at the interface between the electrode and the sealing space and the cavity effect compared to sealing, and the uniformity of luminance and chromaticity on both sides can be improved.

Sectional drawing of the organic EL element which has three light emission units with an example of the structure of the organic EL element of this invention Sectional drawing of the organic EL element which has an example of a structure of the organic EL element of this invention, and has five light emission units. The schematic diagram which showed the distance relationship of the light emission center of the light emission unit which concerns on this invention. Schematic which shows an example of the circuit which drives the organic EL element which has three light emission units of this invention

The organic electroluminescence element of the present invention includes at least a light transmissive substrate, a light transmissive first electrode, an odd number of three or more light emitting units, a plurality of light transmissive intermediate electrodes arranged between the light emitting units, and a light transmissive property. An organic electroluminescence element in which a second electrode and a light-transmitting sealing substrate are laminated in this order and sealed by the light-transmitting sealing substrate, wherein the odd number of the three or more light emitting units are blue, green And at least two kinds of light emitting units selected from light emitting units having red or a light emitting color in which they are mixed, and light emitting units having different light emitting colors are arranged at symmetrical positions with respect to the light emitting unit arranged in the center. It is characterized by doing. This feature is a technical feature common to the inventions according to claims 1 to 5.

As an embodiment of the present invention, from the viewpoint of manifesting the effect of the present invention, the light emission center inside the light emission unit at the symmetrical position of each of the odd number of three or more light emission units is arranged in the center. It is preferable that they are equidistant from the emission center. By adopting such a configuration, it is possible to control the emitted light from both surfaces to have substantially the same luminance and chromaticity, and to transmit the first transparent electrode, the transparent intermediate electrode, and the transparent first. By appropriately applying a current to the two electrodes, the emission color can be freely changed and adjusted.

Further, the light-transmitting substrate and the light-transmitting sealing substrate are both flexible substrates and made of the same material, so that the light-transmitting property and refractive index of the substrate are the same, and the light emission Regardless of the unit design, it is preferable from the viewpoint of obtaining emitted light having substantially the same light emission characteristics from both sides.

Furthermore, it is preferable that the polarity of the plurality of translucent intermediate electrodes is positive, negative, or negative, positive from the translucent substrate side, and the polarity of the electrodes is adjusted as described above. By doing so, light emission from the front and back can be adjusted and the emission color can be freely changed, which is preferable.

In addition, when the first transparent electrode, the transparent intermediate electrode, and the second transparent electrode are all transparent electrodes containing silver as a main component, specular reflection at the metal electrode does not occur. Therefore, it is not necessary to consider the loss of light due to the specular reflection, and the light emission luminance on both surfaces is almost the same, and the transparency of the entire element can be improved.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

<< Outline of the organic electroluminescence device of the present invention >>
The organic electroluminescence element of the present invention (hereinafter referred to as an organic EL element) includes at least a translucent substrate, a translucent first electrode, an odd number of three or more light emitting units, and a plurality of light emitting units disposed between the light emitting units. A translucent intermediate electrode, a translucent second electrode, and a translucent sealing substrate are laminated in this order, and are organic electroluminescence elements sealed by the translucent sealing substrate, wherein the odd number is 3 or more Each light emitting unit uses at least two types of light emitting units selected from blue, green and red, or a light emitting unit in which they are mixed, and different light emitting colors from the light emitting units arranged in the center The light emitting units are arranged at symmetrical positions.

A conventional double-sided light emitting organic EL element including a substrate, a first electrode, a plurality of light emitting units, a plurality of intermediate electrodes arranged between the light emitting units, a second electrode, and a sealing substrate is disclosed in Patent Document 2. In general, the light emitting unit has a structure in which layers emitting blue, green, and red light are stacked.

However, in this configuration, the emission color can be changed and both sides can emit light. However, since the layers emitting different colors such as blue, green and red are laminated, the organic EL element is actually mounted on both sides. From the observation, it was found that the layer order of the layers emitting different colors differed, resulting in a difference in the color tone and brightness of the observed emitted light, and the uniformity of the brightness and chromaticity of the light emitted from both sides was inferior. . In addition, since the configuration is inferior in uniformity of luminance and chromaticity, it has been found that when the emission color is changed, the shift must be corrected each time and complicated adjustment is required.

The light emitting unit according to the present invention uses at least two types of light emitting units selected from light emitting units in which an odd number of three or more light emitting units have blue, green and red, or a light emitting color in which they are mixed, and By arranging light emitting units having different light emission colors in symmetrical positions with respect to the light emitting unit arranged in the center, when the organic EL element is observed from both sides, the layer order of the units emitting different colors is the same. Therefore, the present inventors have found that the uniformity of luminance and chromaticity of light emitted from both surfaces is improved, and an organic EL element that can be easily adjusted when changing the emission color can be obtained.

Moreover, the translucent board | substrate and the said translucent sealing board | substrate which concern on this invention are both flexible substrates, and the translucency and refractive index of a board | substrate become the same by forming from the same material. The inventors have found that uniform light emission characteristics can be obtained on both sides regardless of the design of the light emitting unit.

Further, Patent Document 2 has a problem that transparency is inferior because an ITO film or an aluminum film is used as an anode (anode) or cathode (cathode) material, and an aluminum film or a magnesium-silver film is used as an intermediate electrode. However, the light-transmitting first electrode, the light-transmitting intermediate electrode, and the light-transmitting second electrode according to the present invention are, as a preferred embodiment, an electrode containing silver as a main component, compared with the ITO electrode. Since it can be adjusted to a thin film that does not cause specular reflection at the metal electrode, there is no need to consider the loss of light due to the specular reflection, the light emission luminance on both sides is almost the same, and the transparency of the entire element is Further improve.

In addition, the organic EL element of the present invention is preferably solid-sealed (also referred to as laminate sealing) by the translucent sealing substrate, and thus has a hollow portion applied to a general organic EL element. Compared to sealing, there is almost no reflection at the interface between the electrode and the sealing space and the cavity effect, which contributes to further improvement in chromaticity uniformity on both sides.

<Measurement of luminance and chromaticity of emitted light from both sides>
The organic EL device of the present invention includes at least a light transmissive substrate, a light transmissive first electrode, an odd number of three or more light emitting units, a plurality of light transmissive intermediate electrodes disposed between the light emitting units, and a light transmissive first. An organic electroluminescence device in which two electrodes and a light-transmitting sealing substrate are laminated in this order and sealed by the light-transmitting sealing substrate, is transparent when not emitting light, and uniform from both sides when emitting light The present invention provides an organic electroluminescence element that emits light with brightness and chromaticity and can freely change the emission color.

In the present invention, “when emitting light, light is emitted with uniform brightness and chromaticity from both sides” means, for example, that the light emitting unit emits light in an environment of 23 ° C. and 55 RH, and the substrate from the translucent substrate side. Lx is the luminance of Lx and Ly, and Lx is the light emitted in the normal direction with respect to the substrate from the translucent sealing substrate side. The ratio (%) is obtained by dividing the smaller value of the chromaticity value by the larger value, and the ratio (%) falls within the range of 95 to 100%.

Luminance of light (Lx) emitted in the normal direction from the translucent substrate side to the substrate, and light (Ly) emitted in the normal direction from the translucent sealing substrate side to the substrate The chromaticity can be measured by the following method. These are merely examples, and devices and software having equivalent functions may be used.

<Measurement of luminance and chromaticity>
Measuring instrument: Konica Minolta 2D color luminance meter CA-2500
Data analysis software: Konica Minolta Co., Ltd. data management software CA-S25w
Measurement conditions: In an environment of 23 ° C. and 55% RH, the organic EL element emits light, and light (Lx) emitted in the normal direction from the translucent substrate side to the substrate is placed at a distance of 5 cm from the substrate. Then measure the luminance and chromaticity with the above measuring equipment. Similarly, the luminance and chromaticity of light (Ly) emitted from the translucent sealing substrate side in the normal direction with respect to the substrate is measured at a distance of 5 cm from the substrate with the measuring instrument.

Measure the brightness and chromaticity values as data using the above data analysis software.

* From the obtained luminance and chromaticity data of Lx and Ly, the smaller value is divided by the larger value to obtain a ratio (%), and the difference is verified.

The ratio (%) is obtained by dividing the smaller value of the luminance and chromaticity values of Lx and Ly measured from both sides of the organic EL element by the larger value, and the ratio (%) is 95 to 100%. It is preferable to fall within the range in order to obtain the effect of the present invention that emits light with uniform brightness and chromaticity from both sides during light emission. More preferably, it is in the range of 97 to 100%, and particularly preferably in the range of 99 to 100%.

<Configuration of organic electroluminescence element of the present invention>
The configuration of the organic EL device of the present invention will be described with reference to the drawings. However, the present invention is not limited thereby.

FIG. 1A is a schematic diagram showing an example of the configuration of an organic EL element having three light emitting units according to the present invention.

In the case of the organic EL element 100 having three light emitting units, as shown in FIG. 1A, the light transmitting substrate 105 / the light transmitting first electrode 101 / the light emitting unit 103-1 / the light transmitting intermediate electrode 104-1. / Light emitting unit 103-2 / Translucent intermediate electrode 104-2 / Light emitting unit 103-3 (same as 103-1) / Transparent second electrode 102 / Transparent sealing substrate 106 are laminated in this order. It is basic. The translucent intermediate electrodes may be the same or different.

Each of the light-transmitting first electrode 101 and the light-transmitting intermediate electrode 104-1 is wired with a lead wire, and by applying about 2 to 40V as the driving voltage V1 to each connection terminal, the light emitting unit 103- 1 emits light. Similarly, the light-transmitting intermediate electrode 104-1 and the light-transmitting intermediate electrode 104-2 are also wired with lead wires, and a drive voltage V2 of about 2 to 40 V is applied to the respective connection terminals, whereby the light emitting unit 103-2 emits light. Further, the light-transmitting intermediate electrode 104-2 and the light-transmitting second electrode 102 are also wired with lead wires, and by applying about 2 to 40V as the driving voltage V3 to each connection terminal, the light emitting unit 103- 3 emits light.

Specifically, when the organic EL element 100 is driven, when the DC voltage is applied to the V ₁ , V _2, and V ₃ , the translucent first electrode 101 that is an anode is set to a positive polarity. The translucent second electrode 102 which is a cathode (cathode) has a negative polarity and is applied within a voltage range of 2 to 40 V. Furthermore, an anode (anode) and a cathode (cathode) are applied to the translucent intermediate electrode. Apply an intermediate voltage.

The light emitting units 103-1 and 103-2 use two types of light emitting units selected from blue, green and red, or a light emitting unit having a mixed emission color, and are arranged in the center (103 -2), the light emitting units (103-1, 103-3) of different luminescent colors are arranged at symmetrical positions.

For example, a light emitting unit having a different emission color with respect to a light emitting unit arranged in the center, such as a blue light emitting layer / red light emitting layer / blue light emitting layer structure or a green light emitting layer / red light emitting layer / green light emitting layer structure. Disposing them at symmetrical positions is preferable from the viewpoint of improving the chromaticity and luminance uniformity of light emitted from both surfaces and facilitating adjustment when changing the emission color.

Also, by selecting two types of light emitting units from the light emitting units having the blue, green and red light emitting colors, the two types of mixed color light emission can be freely adjusted. Moreover, white light can also be obtained as an illuminating device that emits light from both sides by selecting two types of emitted light so as to have a complementary color relationship.

In the case where light emission units exhibiting different emission colors are stacked to obtain white light emission, it is preferable that these light emission units have a complementary color relationship with each other. For example, an organic EL element that emits white light can be obtained by providing a blue light-emitting layer and a light-emitting unit that emits a complementary green-yellow, yellow, or orange (orange) light-emitting color. The “complementary color” relationship is a relationship between colors that become achromatic when mixed. That is, white light emission can be obtained by mixing light emission of substances emitting light of complementary colors.

For example, the light emitting unit disposed in the center is a blue light emitting layer including a blue light emitting dopant, and the light emitting units disposed symmetrically on both sides thereof are green and red (yellow) light emitting units including a green light emitting dopant and a red light emitting dopant. If there is, white light can be obtained.

FIG. 1B is a schematic diagram showing an example of the configuration of an organic EL element having a five-layer light-emitting unit of the present invention.

In the case of the organic EL element 100 having a five-layer light emitting unit, as shown in FIG. 1B, the light transmitting substrate 105 / the light transmitting first electrode 101 / the light emitting unit 103-1 / the light transmitting intermediate electrode 104-1. / Light emitting unit 103-2 / Translucent intermediate electrode 104-2 / Light emitting unit 103-3 / Translucent intermediate electrode 104-3 / Light emitting unit 103-4 (same as light emitting unit 103-2) / Translucent intermediate Basically, the electrode 104-4 / the light emitting unit 103-5 (the light emitting unit 103-1) / the light transmissive second electrode 102 / the light transmissive sealing substrate 106 are laminated in this order. The translucent intermediate electrodes may be the same or different.

The light emitting units 103-1, 103-2, 103-3, 103-4 and 103-5 are preferably light emitting units having blue, green and red, or a light emitting color obtained by mixing them, and in the center. It is preferable that the light emitting units of different emission colors are arranged at symmetrical positions with respect to the light emitting units to be arranged.

For example, the light emitting units 103-1, 103-2, 103-3, 103-4 and 103-5 have a configuration of blue light emitting layer / green light emitting layer / red light emitting layer / green light emitting layer / blue light emitting layer. However, it is preferable from the viewpoint that the chromaticity and luminance uniformity of the light emitted from both surfaces are improved and the adjustment when changing the emission color can be easily performed. Further, by using the light emitting unit having blue, green and red light emission colors, uniform full color light emission can be performed from both sides, which is extremely useful as a double-sided display.

In addition, when the light emission centers inside the light emission units at the symmetrical positions of the odd number of the light emission units of 3 or more are respectively equidistant from the light emission centers of the light emission units arranged in the center, it is observed from both sides. The brightness and chromaticity of the emitted light can be observed uniformly, which is preferable.

FIG. 2 is a schematic diagram showing the distance relationship between the light emission centers of the light emitting unit according to the present invention.

FIG. 2 is a schematic diagram of the organic EL element including the three light emitting units shown in FIG. 1A, and shows the emission center h ₁ of the light emitting unit 103-1 with respect to the emission center h ₂ of the central light emitting unit 103-2. the distance _{d 1,} the distance _{d 2} of the emission center _{h 3} of the light-emitting unit 103-3 to the light emitting centers _{h 2} of the central light-emitting unit _103-2, it is preferable that d 1 = _{d 2.}

Here, the “light emission center” refers to a position where the light emission energy has a peak when the light emission energy in the thickness direction of the light emission unit described later is measured. Specifically, it can be specified by the method described in JP2009-181829A.

The position of the light emission center of the light emitting unit having the structure to be described later varies depending on the type of the organic layer to be stacked, the layer thickness, etc., but is arranged at a symmetrical position with the light emission center of the light emitting unit arranged in the center as the starting point. By adjusting the distance from the light emission center of the light emitting unit to be equal to each other, the uniformity of the chromaticity and luminance of light emitted from both surfaces is improved, and this is preferable from the viewpoint of easy adjustment when changing the light emission color. .

Usually, in order to realize a white light emitting element and a full color light emitting element with high efficiency and long life, it is necessary to stack a plurality of light emitting units. Fluctuation is likely to occur.

In a normal pair of electrode configurations, for example, the electron mobility is about 1 × 10 ⁻⁵ cm ² / Vs and the hole mobility is about 1 × 10 ⁻⁷ cm ² / Vs due to the transportability of the carrier transport material. Therefore, it is considered that light is emitted at the interface close to the hole transport layer in the light emitting unit.

Therefore, when a plurality of light emitting units are used, the light emitting units located on the hole transport layer side easily emit light. The position of the light emission center is controlled by the layer configuration and the layer thickness, and as described above, the light emission center of the light emission unit arranged at the symmetrical position with the light emission center of the light emission unit arranged at the center as the starting point. Adjusting the distance to the same distance is a preferable aspect for obtaining emitted light having uniform luminance and chromaticity from both sides.

Hereinafter, details of each main layer for constituting the organic EL element 100 described above and a manufacturing method thereof will be further described.

[Translucent substrate]
“Translucency” as used in the present invention is described in JIS K 7105: 1981 using the spectrophotometer (U-3300, manufactured by Hitachi High-Technologies Corporation) for each of the substrate, the electrode, and the light emitting layer. When the light transmittance (%) at a light wavelength of 550 nm is measured by the method, it means having a light transmittance of 50% or more. The light transmittance of each element constituting the organic EL element is preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more.

Further, the organic EL element of the present invention is a double-sided light emitting type, and in order to meet the demand for free design, the light transmittance of the entire organic EL element at a light wavelength of 550 nm is preferably 50% or more, More preferably, it is 65% or more, and particularly preferably 75% or more.

The translucent substrate according to the present invention is preferably a flexible substrate.

The flexible substrate as used in the present invention refers to a substrate that is wound around a φ (diameter) 50 mm roll and does not crack before and after winding with a constant tension, and more preferably a substrate that can be wound around a φ30 mm roll.

Examples of the flexible substrate according to the present invention include a resin substrate, a thin film metal foil, and a thin plate flexible glass.

Examples of the resin substrate applicable to the present invention include polyesters such as polyethylene terephthalate (abbreviation: PET), polyethylene naphthalate (abbreviation: PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, and cellulose triacetate (abbreviation: TAC). Cellulose acetate butyrate, cellulose acetate propionate (abbreviation: CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate and their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, Polycarbonate (abbreviation: PC), norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfone (Abbreviation: PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic and polyarylates, Arton (trade name, manufactured by JSR) and Appel (product) Name, manufactured by Mitsui Chemicals, Inc.) and the like.

Among these resin substrates, films such as polyethylene terephthalate (abbreviation: PET), polybutylene terephthalate, polyethylene naphthalate (abbreviation: PEN), polycarbonate (abbreviation: PC) are flexible resin substrates in terms of cost and availability. Are preferably used.

The resin substrate may be an unstretched film or a stretched film.

The resin substrate applicable to the present invention can be manufactured by a conventionally known general film forming method. For example, an unstretched resin substrate that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it with an annular die or a T-die, and quenching. In addition, the resin substrate transport direction (vertical axis direction, MD) is applied to the unstretched resin substrate by a known method such as uniaxial stretching, tenter sequential biaxial stretching, tenter simultaneous biaxial stretching, tubular simultaneous biaxial stretching, or the like. Direction) or a direction (horizontal axis direction, TD direction) perpendicular to the transport direction of the resin substrate, the stretched resin substrate can be produced. The draw ratio in this case can be appropriately selected according to the resin as the raw material of the resin substrate, but is preferably in the range of 2 to 10 times in the vertical axis direction and the horizontal axis direction.

The thickness of the resin substrate is preferably a thin resin substrate in the range of 3 to 200 μm, more preferably in the range of 10 to 150 μm, and particularly preferably in the range of 20 to 120 μm. is there.

Further, the thin flexible glass applicable as the flexible substrate according to the present invention is a glass plate that is thin enough to be bent. The thickness of the thin flexible glass can be appropriately set within the range in which the thin flexible glass exhibits flexibility.

Examples of the thin flexible glass include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. The thickness of the thin flexible glass is, for example, in the range of 5 to 300 μm, and preferably in the range of 20 to 150 μm.

In the organic EL element of the present invention, a gas barrier layer may be provided on the above-described translucent substrate as necessary. The gas barrier layer has a water vapor permeability (25 ± 0.5 ° C., relative humidity 90 ± 2% environment) measured by a method according to JIS K 7129: 1992, 0.01 g / (m ² · 24 hours. ) The following gas barrier layer (also referred to as a gas barrier film or the like) is preferable, and the oxygen permeability measured by a method according to JIS K 7126: 1987 is 1 × 10 ⁻³ ml / (m ² · It is more preferable that the high gas barrier layer has a water vapor permeability of 1 × 10 ⁻⁵ g / (m ² · 24 hours) or less.

As a material for forming the gas barrier layer, any material that has a function of suppressing intrusion of water or oxygen that causes deterioration of the organic EL element may be used. For example, an inorganic substance such as silicon oxide, silicon dioxide, or silicon nitride may be used. Can be used. Furthermore, in order to improve the brittleness of the gas barrier layer, it is more preferable to have a laminated structure of these inorganic layers and organic layers made of organic materials. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

The method for forming the gas barrier layer is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method and the like can be used, but an atmospheric pressure plasma polymerization method described in JP-A-2004-68143 is preferable.

[Translucent first electrode: anode electrode (anode)]
As the translucent first electrode constituting the organic EL element, a metal such as Ag or Au or an alloy containing a metal as a main component, CuI or indium-tin composite oxide (ITO), SnO _2, ZnO or the like Although a metal oxide can be mentioned, it is preferably a metal or an alloy containing a metal as a main component, more preferably silver or an alloy containing silver as a main component.

When the translucent first electrode is composed mainly of silver, the purity of silver is preferably 99% or more. Further, palladium (Pd), copper (Cu), gold (Au), or the like may be added to ensure the stability of silver.

The translucent first electrode is a layer composed mainly of silver, but specifically, it may be formed of silver alone or an alloy containing silver (Ag). . Examples of such alloys include silver / magnesium (Ag / Mg), silver / copper (Ag / Cu), silver / palladium (Ag / Pd), silver / palladium / copper (Ag / Pd / Cu), silver -Indium (Ag.In) etc. are mentioned.

Among the constituent materials composing the translucent first electrode, the electrode composing the organic EL device of the present invention is composed of silver as a main component and translucent having a thickness in the range of 2 to 20 nm. The electrode is preferably a conductive electrode, but more preferably has a thickness in the range of 4 to 12 nm. A thickness of 20 nm or less is preferable because the light-absorbing and reflecting components of the translucent electrode are kept low and high light transmittance is maintained.

The layer composed mainly of silver in the present invention means that the silver content of the translucent first electrode is 60% by mass or more, preferably the silver content is 80% by mass or more. More preferably, the silver content is 90% by mass or more, and particularly preferably the silver content is 98% by mass or more.

The translucent first electrode may have a configuration in which a layer composed mainly of silver is divided into a plurality of layers as necessary.

In the present invention, when the first electrode is a translucent electrode composed mainly of silver, from the viewpoint of increasing the uniformity of the silver film of the translucent electrode to be formed, It is preferable to provide an underlayer. Although there is no restriction | limiting in particular as a base layer, It is preferable that it is a layer containing the organic compound which has a nitrogen atom or a sulfur atom, and the method of forming the translucent 1st electrode on the said base layer is a preferable aspect. is there.

Examples of the method for forming the light-transmitting first electrode include a method using a wet process such as a coating method, an inkjet method, a coating method, a dip method, a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, and a CVD method. A method using a dry process such as, for example, is mentioned, but it is preferable to form by a vapor deposition method.

As a vapor deposition method, a vacuum vapor deposition method is mainly used, and silver, which is a constituent material of a transparent anode (anode), or other alloy as necessary is applied to a resistance heating boat for vapor deposition in a vacuum vapor deposition apparatus. Fill. The resistance heating boat for vapor deposition is made of molybdenum or tungsten. When forming the transparent anode (anode), the vacuum degree in the vacuum deposition apparatus is reduced to, for example, a range of 1 × 10 ⁻² to 1 × 10 ⁻⁶ Pa, and then a transparent anode (anode) forming material such as silver The above-mentioned resistance heating boat for vapor deposition containing is heated and energized, and a silver thin film is vapor-deposited on a resin base material or an underlayer at a predetermined vapor deposition rate (nm / second) to obtain a thickness of 2 to 20 nm. A transparent anode (anode) in the range of is formed.

In addition, since the first transparent electrode is formed on the base layer, the first transparent electrode can be sufficiently conductive without a high-temperature annealing treatment (for example, a heating process at 150 ° C. or higher) after the formation. .

In the organic EL element of the present invention, when the translucent first electrode is an electrode composed mainly of silver, at least at a position adjacent to the translucent substrate side of the translucent first electrode. It is a preferable aspect to have an underlayer containing an organic compound having a nitrogen atom or a sulfur atom, and further, the nitrogen compound having an effective unshared electron pair in which the organic compound contained in the underlayer does not participate in aromaticity It is preferable that it is a compound which has this.

In the present invention, when the light-transmitting first electrode mainly composed of silver is provided, a transparent anode (anode) is formed by providing a base layer containing an organic compound having a nitrogen atom or a sulfur atom below the first electrode. During the formation, the silver atoms interact with the nitrogen atoms or sulfur atoms of the organic compound contained in the underlayer, and as a result, the diffusion distance of silver atoms on the underlayer surface decreases and the silver agglomerates. Formation of aggregates can be suppressed, and a light-transmitting electrode film having high uniformity can be formed.

In general, silver atoms are likely to be isolated like islands by nuclear growth type (Volume-Weber: VW type) film growth, but by single layer growth type (Frank-van der Merwe: FM type) film growth A film is formed. Therefore, a transparent first electrode with a uniform film thickness can be obtained while having a thin film thickness.

In the present invention, the organic compound having at least a nitrogen atom or a sulfur atom is not particularly limited. For example, International Publication No. 2013/105569, International Publication No. 2013/141097, International Publication No. 2013/161750 Mention may be made of the compounds described.

With the above configuration, the translucent first electrode can achieve both improved conductivity and improved light transmission.

[Light emitting unit]
The organic EL device of the present invention is characterized by having an odd number of light emitting units of at least 3 or more. Examples of the configuration of each light emitting unit include the following configurations.

The following is a typical example of the configuration of the light emitting unit. Here, the light emitting unit collectively refers to a functional layer existing between an anode (anode) and a cathode (cathode).

(I) (anode (anode) side) / hole injection transport layer / light emitting layer / electron injection transport layer / (cathode (cathode) side)
(Ii) (anode (anode) side) / hole injection transport layer / light emitting layer / hole blocking layer / electron injection transport layer / (cathode (cathode) side)
(Iii) (anode (anode) side) / hole injection transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron injection transport layer / (cathode (cathode) side)
(Iv) (anode (anode) side) / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / (cathode (cathode) side)
(V) (anode (anode) side) / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / (cathode (cathode) side)
(Vi) (anode (anode) side) / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / (cathode (cathode) side)
A non-light emitting intermediate layer may be provided between the light emitting layers. The intermediate layer may be a charge generation layer or a multi-photon unit configuration.

As for the outline of the light emitting unit applicable to the present invention, for example, JP2013-157634A, JP2013-168552A, JP2013-177361A, JP2013-187221A, JP2013-2013A. -191644, JP2013-191804, JP2013-225678, JP2013-235994, JP2013-243234, JP2013-243236, JP2013-242366 JP, 2013-243371, JP 2013-245179, JP 2014-003249, JP 2014-003299, JP 2014-013910, JP 2014-014933 , JP 2014-017494 A It can be mentioned configurations described in equal.

<Light emitting layer>
The light emitting layer constituting the light emitting unit preferably has a structure containing a light emitting material, and the light emitting material is preferably a phosphorescent compound or a fluorescent compound.

This light emitting layer is a layer that emits light by recombination of electrons injected from the electrode or the electron transport layer and holes injected from the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. Alternatively, it may be the interface between the light emitting layer and the adjacent layer.

Such a light emitting layer is not particularly limited in its configuration as long as the light emitting material contained satisfies the light emission requirements. Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength. In this case, it is preferable to have a non-light emitting intermediate layer between the light emitting layers.

The total thickness of the light emitting layers is preferably in the range of 1 to 100 nm, and more preferably in the range of 1 to 30 nm because a lower driving voltage can be obtained. In addition, the sum total of the thickness of a light emitting layer is the thickness also including the said intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

The light emitting layer as described above may be formed by using a light emitting material or a host compound described later, for example, a known method such as a vacuum deposition method, a spin coating method, a casting method, an LY method (Langmuir-Blodget, Lxngmuir Blodgett method), and an ink jet method. Can be formed.

In the light emitting layer, a plurality of light emitting materials may be mixed, and a phosphorescent light emitting material and a fluorescent light emitting material (also referred to as a fluorescent dopant or a fluorescent compound) may be mixed and used in the same light emitting layer. The structure of the light-emitting layer preferably includes a host compound (also referred to as a light-emitting host) and a light-emitting material (also referred to as a light-emitting dopant compound), and emits light from the light-emitting material.

(Host compound)
As the host compound contained in the light emitting layer, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable. Further, the phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.

As the host compound, a known host compound may be used alone, or a plurality of types of host compounds may be used. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. In addition, by using a plurality of kinds of light emitting materials described later, it is possible to mix different light emission, thereby obtaining an arbitrary light emission color.

The host compound used in the light emitting layer may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). )

Examples of host compounds applicable to the present invention include, for example, JP-A Nos. 2001-257076, 2001-357777, 2002-8860, 2002-43056, 2002-105445, 2002-352957, 2002-231453, 2002-234888, 2002-260861, 2002-305083, US Patent Application Publication No. 2005/0112407, US Patent Application Publication No. 2009/0030202, International Publication No. 2001/039234, International Publication No. 2008/056746, International Publication No. 2005/089025, International Publication No. 2007/063754, International Publication No. 2005/030900, International Publication 200th / No. 086,028, WO 2012/023947, can be mentioned JP 2007-254297, JP-European compounds described in Japanese Patent No. 2034538 Pat like.

(Luminescent material)
As the light-emitting material that can be used in the present invention, a phosphorescent compound (also referred to as a phosphorescent compound, a phosphorescent material, or a phosphorescent dopant) and a fluorescent compound (both a fluorescent compound or a fluorescent material) are used. Say).

The phosphorescent compound is a compound in which light emission is observed during the deactivation process from the excited triplet state to the ground state, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), Although the phosphorescence quantum yield is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C., the preferred phosphorescence quantum yield is 0.1 or more.

The phosphorescent quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of the Fourth Edition Experimental Chemistry Course 7. The phosphorescence quantum yield in the solution can be measured using various solvents, but when using a phosphorescent compound in the present invention, the phosphorescence quantum yield is 0.01 or more in any solvent. Should be achieved.

The phosphorescent compound can be appropriately selected from known compounds used for the light-emitting layer of a general organic EL device, but preferably contains a group 8 to 10 metal in the periodic table of elements. More preferred are iridium compounds, more preferred are iridium compounds, osmium compounds, platinum compounds (platinum complex compounds) or rare earth complexes, and most preferred are iridium compounds.

In the present invention, at least one light emitting layer may contain two or more phosphorescent compounds, and the concentration ratio of the phosphorescent compounds in the light emitting layer varies in the thickness direction of the light emitting layer. It may be an embodiment.

Specific examples of known phosphorescent compounds that can be used in the present invention include compounds described in the following documents.

Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), International Publication No. 2009/100991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Application Publication No. 2006/835469, US Patent Application Publication No. 2006 /. Examples thereof include compounds described in US Patent No. 0202194, US Patent Application Publication No. 2007/0087321, US Patent Application Publication No. 2005/0244673, and the like.

Also, Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chem. Lett. 34, 592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42, 1248 (2003), International Publication No. 2009/050290, International Publication No. 2009/000673, US Pat. No. 7,332,232, US Patent Application Publication No. 2009/0039776, US Pat. No. 6,687,266, US Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2008/0015355, US Pat. No. 7,396,598, US Patent Application Publication No. 2003/0138667, US Pat. No. 7090928 And the like.

Also, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74, 1361 (1999), International Publication No. 2006/056418, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2006/082742, US Patent Application Publication No. 2005/0260441. , U.S. Pat. No. 7,534,505, U.S. Patent Application Publication No. 2007/0190359, U.S. Pat. No. 7,338,722, U.S. Pat. No. 7,279,704, U.S. Patent Application Publication No. 2006/103874, etc. Mention may also be made of the compounds described.

Furthermore, International Publication No. 2005/076380, International Publication No. 2008/140115, International Publication No. 2011/134013, International Publication No. 2010/086089, International Publication No. 2012/020327, International Publication No. 2011/051404. Further, compounds described in International Publication No. 2011/073149, JP2009-114086, JP2003-81988, JP2002-363552, and the like can also be mentioned.

In the present invention, preferred phosphorescent compounds include organometallic complexes having Ir as a central metal. More preferably, a complex containing at least one coordination mode of metal-carbon bond, metal-nitrogen bond, metal-oxygen bond, and metal-sulfur bond is preferable.

The phosphorescent compound described above (also referred to as a phosphorescent metal complex) is described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, pp. 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, pages 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, pages 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), European Journal of Organic Chemistry, Vol. 4, pages 695-709 (2004), and methods disclosed in the references and the like described in these documents Can be synthesized.

Fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes. And dyes, polythiophene dyes, and rare earth complex phosphors.

<Organic functional layer group excluding luminescent layer>
Next, each layer other than the light emitting layer constituting the light emitting unit will be described in the order of the charge injection layer, the hole transport layer, the electron transport layer, and the blocking layer.

(Charge injection layer)
The charge injection layer is a layer provided between the electrode and the light emitting layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its industrialization front line (November 30, 1998, NT. The details are described in Volume 2, Chapter 2, “Electrode Materials” (pages 123 to 166) of “Part 2” of S Co., Ltd., and there are a hole injection layer and an electron injection layer.

In general, the charge injection layer is between the anode (anode) and the light emitting layer or hole transport layer if it is a hole injection layer, or the cathode (cathode) and light emitting layer or electron transport layer if it is an electron injection layer. However, the present invention is characterized in that the charge injection layer is disposed adjacent to the transparent electrode. When used in an intermediate electrode, it is sufficient that at least one of the adjacent electron injection layer and hole injection layer satisfies the requirements of the present invention.

The hole injection layer is a layer disposed adjacent to the anode (anode) which is a transparent electrode in order to lower the driving voltage and improve the luminance of light emission. “The organic EL element and its industrialization front line (November 1998) (Published by NTS, Inc., 30th) ”, the second volume, Chapter 2,“ Electrode Materials ”(pages 123 to 166).

The details of the hole injection layer are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. Examples of materials used for the hole injection layer include: , Porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stilbene derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives, Indolocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, polyvinylcarbazole, aromatic amines introduced into the main chain or side chain Child material or oligomer, polysilane, a conductive polymer or oligomer (e.g., PEDOT (polyethylene dioxythiophene): PSS (polystyrene sulfonic acid), aniline copolymers, polyaniline, polythiophene, etc.) and the like can be mentioned.

Examples of the triarylamine derivative include benzidine type represented by α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), and MTDATA (4,4 ′, 4 ″). Examples include a starburst type represented by -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine), a compound having fluorene or anthracene in the triarylamine-linked core.

In addition, hexaazatriphenylene derivatives such as those described in JP-T-2003-519432 and JP-A-2006-135145 can also be used as a hole transport material.

The electron injection layer is a layer provided between the cathode (cathode) and the light emitting layer for lowering the driving voltage and improving the light emission luminance. The cathode (cathode) is a light-transmitting material mainly composed of silver or silver. In the case of a conductive electrode, it is provided adjacent to the transparent electrode, and “Organic EL element and its forefront of industrialization” (issued on November 30, 1998 by NTT) The electrode material "(pages 123 to 166) is described in detail.

Details of the electron injection layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specific examples of materials preferably used for the electron injection layer are as follows. Metals represented by strontium and aluminum, alkali metal compounds represented by lithium fluoride, sodium fluoride, potassium fluoride, etc., alkali metal halide layers represented by magnesium fluoride, calcium fluoride, etc. Examples thereof include an alkaline earth metal compound layer typified by magnesium, a metal oxide typified by molybdenum oxide and aluminum oxide, and a metal complex typified by lithium 8-hydroxyquinolate (Liq). Moreover, when the transparent electrode in this invention is a cathode (cathode), organic materials, such as a metal complex, are used especially suitably. The electron injection layer is preferably a very thin film, and depending on the constituent material, the layer thickness is preferably in the range of 1 nm to 10 μm.

(Hole transport layer)
The hole transport layer is made of a hole transport material having a function of transporting holes. In a broad sense, the hole injection layer and the electron blocking layer also have the function of a hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

The hole transport material has any of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples include stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers, and thiophene oligomers.

As the hole transport material, those described above can be used, but porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds can be used, and in particular, aromatic tertiary amine compounds can be used. preferable.

Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl, N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 2,2-bis (4-di-p-tolylaminophenyl) propane, 1,1 -Bis (4-di-p-tolylaminophenyl) cyclohexane, N, N, N ', N'-tetra-p-tolyl-4,4'-diaminobiphenyl, 1,1-bis (4-di-p -Tolylaminophenyl) -4-phenylcyclohexane, bis (4-dimethylamino-2-methylphenyl) phenylmethane, bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N N'-di (4-methoxyphenyl) -4,4'-diaminobiphenyl, N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis (diphenylamino) Quadriphenyl, N, N, N-tri (p-tolyl) amine, 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene, 4-N, N -Diphenylamino- (2-diphenylvinyl) benzene, 3-methoxy-4'-N, N-diphenylaminostilbenzene, N-phenylcarbazole and the like.

For the hole transport layer, the hole transport material may be formed by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, and an LY method (Langmuir Brodget, Lxngmuir Brodgett method). Thus, it can be formed by thinning. The layer thickness of the hole transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

Also, the p property can be increased by doping impurities into the material of the hole transport layer. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175 and J.P. Appl. Phys. 95, 5773 (2004), and the like.

Thus, it is preferable to increase the p property of the hole transport layer because an element with lower power consumption can be manufactured.

(Electron transport layer)
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer structure or a stacked structure of a plurality of layers.

In the electron transport layer having a single-layer structure and the electron transport layer having a multilayer structure, an electron transport material (also serving as a hole blocking material) constituting a layer portion adjacent to the light emitting layer is used as an electron transporting material. What is necessary is just to have the function to transmit. As such a material, any one of conventionally known compounds can be selected and used. Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane, anthrone derivatives, and oxadiazole derivatives. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as a material for the electron transport layer. it can. Furthermore, a polymer material in which these materials are introduced into a polymer chain, or a polymer material having these materials as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (abbreviation: Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8- Quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (abbreviation: Znq), etc. and the central metal of these metal complexes A metal complex replaced with In, Mg, Cu, Ca, Sn, Ga, or Pb can also be used as a material for the electron transport layer.

The electron transport layer can be formed by thinning the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, and an LY method. The thickness of the electron transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The electron transport layer may have a single structure composed of one or more of the above materials.

(Blocking layer)
The blocking layer includes a hole blocking layer and an electron blocking layer, and is a layer provided as necessary in addition to the constituent layers of the organic functional layer unit 3 described above. For example, it is described in JP-A Nos. 11-204258 and 11-204359, and “Organic EL elements and the forefront of industrialization (published by NTT Corporation on November 30, 1998)” on page 237. Hole blocking (hole block) layer and the like.

The hole blocking layer has a function of an electron transport layer in a broad sense. The hole blocking layer is made of a hole blocking material that has a function of transporting electrons but has a very small ability to transport holes, and recombines electrons and holes by blocking holes while transporting electrons. Probability can be improved. Moreover, the structure of an electron carrying layer can be used as a hole-blocking layer as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer.

On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense. The electron blocking layer is made of a material that has the ability to transport holes and has a very small ability to transport electrons. By blocking holes while transporting holes, the probability of recombination of electrons and holes is improved. Can be made. Moreover, the structure of a positive hole transport layer can be used as an electron blocking layer as needed. The layer thickness of the hole blocking layer applied to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.

(Translucent intermediate electrode)
In the organic EL device of the present invention, a plurality of light emitting units are configured between an anode (anode) and a cathode (cathode), and independent connection for obtaining an electrical connection between the plurality of light emitting units. The structure is separated by a translucent intermediate electrode having a terminal.

The material that can be used as the translucent intermediate electrode is the same as that of the above-described translucent first electrode. Among them, it is preferable that the electrode is composed of silver or an alloy containing silver as a main component. Is a preferred embodiment having an underlayer containing an organic compound having at least a nitrogen atom or a sulfur atom as described above at a position adjacent to the translucent intermediate electrode.

[Translucent second electrode]
The translucent second electrode is an electrode film that functions to supply electrons to the organic functional layer group and the light emitting layer, and a metal, an alloy, an organic or inorganic conductive compound, or a mixture thereof is used. Specifically, gold, aluminum, silver, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, indium, lithium / aluminum mixture, rare earth metal, ITO, ZnO, TiO Oxide semiconductors such as ₂ and SnO ₂ .

The translucent second electrode can be produced by forming a thin film of these conductive materials by a method such as vapor deposition or sputtering. The sheet resistance as the second electrode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 5 nm to 5 μm, preferably 5 to 200 nm.

Note that the organic EL element of the present invention is a double-sided light emitting type in which emitted light is extracted also from the cathode (cathode) side. Therefore, an electrode having good light transmittance may be selected and configured.

Among them, like the translucent first electrode, an electrode composed of silver or an alloy containing silver as a main component is preferable, and in this case, the above-described position is adjacent to the translucent intermediate electrode. It is a preferable embodiment to have an underlayer containing an organic compound having at least a nitrogen atom or a sulfur atom.

[Translucent sealing substrate]
As a sealing means used for sealing the organic EL element of the present invention, a light-emitting unit and an electrode group are solid-sealed with an adhesive on a light-transmitting substrate (laminate sealing). ).

The translucent sealing substrate may be disposed so as to cover the display area of the organic EL element, and may be concave or flat as long as it is translucent, and the electrical insulation is not particularly limited.

Specifically, it is preferably a flexible substrate formed of the same material as the light-transmitting substrate. By forming the substrate from the same material, the light-transmitting property of the substrate and the refractive index inside the element become the same. Regardless of the design of the light emitting unit, it is preferable because uniform light emitting characteristics can be obtained on both sides.

Further, examples of the thin flexible glass applicable to the present invention include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. The thickness of the thin flexible glass is, for example, in the range of 5 to 300 μm, and preferably in the range of 20 to 150 μm.

As the translucent sealing substrate, a resin film can be preferably used from the viewpoint of reducing the thickness of the organic EL element. Further, the resin film has a water vapor transmission rate of 1 × 10 ⁻³ g / m ² .multidot.m at a temperature of 25 ± 0.5 ° C. and a relative humidity of 90 ± 2% RH measured by a method according to JIS K 7129-1992. The oxygen permeability measured by a method according to JIS K 7126-1987 is preferably 1 × 10 ⁻³ ml / m ² · 24 h · atm (1 atm is 1.01325 × 10 ⁵ a Pa) equal to or lower than a temperature of 25 ± 0.5 ° C., water vapor permeability at a relative humidity of 90 ± 2% RH is preferably not more than ^{^{1 × 10 -3 g / m 2}} · 24h.

In order to provide such a gas barrier property, it is preferable to provide the above-described gas barrier layer on the light-transmitting sealing substrate in the same manner as the light-transmitting substrate.

(Laminate sealing method)
A method for performing laminate sealing (solid sealing) with a light-transmitting sealing substrate is not particularly limited. For example, the organic EL element is subjected to an environment in which oxygen and moisture concentrations are constant (for example, an oxygen concentration of 10 ppm or less). Placed in a glove box having a moisture concentration of 10 ppm or less, etc.) and pressed under a reduced pressure (1 × 10 ⁻³ MPa or less) while applying pressure, and the adhesive layer formed on the translucent sealing substrate The organic EL element 100 is laminated and sealed, and then the adhesive layer is thermally cured by heating with a hot air circulation oven, an infrared heater, a heat gun, a high frequency induction heating device, a heat tool, or the like.

There are no particular restrictions on the adhesive, but specific examples include various thermosetting resins such as epoxy resins, cyanate ester resins, phenol resins, bismaleimide-triazine resins, polyimide resins, acrylic resins, and vinylbenzyl resins. preferable. Among these, an epoxy resin is preferable from the viewpoint of low-temperature curability and adhesiveness.

As an epoxy resin, those having an average of two or more epoxy groups per molecule may be used. Specifically, bisphenol A type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, and naphthol type epoxy are used. Resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy resin, aromatic glycidylamine type epoxy resin (specifically, tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, Diglycidyl toluidine, diglycidyl aniline, etc.), alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin , Epoxy resin having a butadiene structure, phenol aralkyl type epoxy resin, epoxy resin having a dicyclopentadiene structure, diglycidyl etherified product of bisphenol, diglycidyl etherified product of naphthalenediol, glycidyl etherified product of phenol, and diester of alcohol Examples thereof include glycidyl etherified products, and alkyl-substituted products, halides, and hydrogenated products of these epoxy resins. These may be used alone or in combination of two or more.

Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, biphenyl aralkyl type epoxy resin, phenol aralkyl type epoxy from the viewpoint of maintaining high heat resistance and low moisture permeability of the resin composition. A resin, an aromatic glycidylamine type epoxy resin, an epoxy resin having a dicyclopentadiene structure, and the like are preferable.

The epoxy resin may be liquid, solid, or both liquid and solid. Here, “liquid” and “solid” are states of the epoxy resin at 25 ° C. From the viewpoints of coatability, processability, adhesiveness, and the like, it is preferable that 10% by mass or more of the entire epoxy resin to be used is liquid.

The epoxy resin preferably has an epoxy equivalent in the range of 100 to 1000, more preferably in the range of 120 to 1000, from the viewpoint of reactivity. Here, the epoxy equivalent is the number of grams (g / eq) of a resin containing 1 gram equivalent of an epoxy group, and is measured according to the method defined in JIS K-7236.

The curing agent for the epoxy resin is not particularly limited as long as it has a function of curing the epoxy resin, but from the viewpoint of suppressing thermal deterioration of the element (particularly the organic EL element) during the curing treatment of the resin composition. The curing treatment of the composition is preferably performed at 140 ° C. or lower, more preferably 120 ° C. or lower, and the curing agent preferably has an epoxy resin curing action in such a temperature range.

Specific examples include primary amines, secondary amines, tertiary amine-based curing agents, polyaminoamide-based curing agents, dicyandiamide, and organic acid dihydrazides. Among these, amine adduct-based compounds ( Amicure PN-23, Amicure MY-24, Amicure PN-D, Amicure MY-D, Amicure PN-H, Amicure MY-H, Amicure PN-31, Amicure PN-40, Amicure PN-40J, etc. (all Ajinomoto Fine Techno)), organic acid dihydrazide (Amicure VDH-J, Amicure UDH, Amicure LDH, etc. (all manufactured by Ajinomoto Fine Techno Co.)) and the like are preferable. These may be used alone or in combination of two or more.

The epoxy resin has extremely good low-temperature curability, and the upper limit of the curing temperature is preferably 140 ° C. or less, more preferably 120 ° C. or less, and even more preferably 110 ° C. or less. On the other hand, from the viewpoint of securing the adhesiveness of the cured product, the lower limit of the curing temperature is preferably 50 ° C. or higher, and more preferably 55 ° C. or higher. Moreover, 120 minutes or less is preferable, as for the upper limit of hardening time, 90 minutes or less are more preferable, and 60 minutes or less are still more preferable. On the other hand, from the viewpoint of surely curing the cured product, the lower limit of the curing time is preferably 20 minutes or more, and more preferably 30 minutes or more. Thereby, the thermal deterioration of the organic EL element can be extremely reduced.

[Other components]
(Extraction electrode)
The extraction electrode is for electrically connecting the translucent first electrode, translucent intermediate electrode, translucent second electrode, and external power source, and the material thereof is not particularly limited and is publicly known. However, for example, a metal film such as a MAM electrode (Mo / Al · Nd alloy / Mo) having a three-layer structure can be used.

(Auxiliary electrode)
The auxiliary electrode is provided for the purpose of reducing the resistance of the translucent electrode, and is provided in contact with the translucent first electrode. The material for forming the auxiliary electrode is preferably a metal having low resistance such as gold, platinum, silver, copper, or aluminum. Since these metals have low light transmittance, a pattern is formed in a range not affected by extraction of the emitted light h from the light extraction surface. Examples of a method for forming such an auxiliary electrode include a vapor deposition method, a sputtering method, a printing method, an ink jet method, and an aerosol jet method. The line width of the auxiliary electrode is preferably 50 μm or less from the viewpoint of the aperture ratio for extracting light, and the thickness of the auxiliary electrode is preferably 1 μm or more from the viewpoint of conductivity.

(Protective film, protective plate)
The protective film or the protective plate is for mechanically protecting the organic EL element, and particularly when the sealing material is a sealing film, the mechanical protection for the organic EL element is not sufficient. It is preferable to provide such a protective film or protective plate.

As the above protective film or protective plate, a glass plate, a polymer plate, a resin film thinner than this, a metal plate, a metal film thinner than this, a polymer material film or a metal material film is applied. Among these, it is particularly advantageous for translucency, and it is preferable to use a resin film because it is lightweight and thin.

[Method for producing organic EL element]
As a method for producing the organic EL element of the present invention, as a minimum configuration, a translucent first electrode (anode), a light emitting unit-1, a translucent intermediate electrode-1, and a light emitting unit-2 are provided on a translucent substrate. The light-transmitting intermediate electrode-2, the light-emitting unit-3 (same as the light-emitting unit-1), the light-transmitting second electrode (cathode) and the light-transmitting sealing substrate are stacked to form a laminate. .

First, a translucent substrate is prepared, and a thin film made of a desired electrode material, for example, an anode (anode) material is formed on the translucent substrate to a thickness of 1 μm or less, preferably in the range of 10 to 200 nm. In this manner, an anode (anode) is formed by a method such as vapor deposition or sputtering. At the same time, a connection electrode portion connected to an external power source is formed at the end of the anode (anode).

Next, a hole injection layer and a hole transport layer constituting the light-emitting unit-1, a light-emitting layer, an electron transport layer constituting the organic functional layer group 2 and the like are sequentially laminated thereon.

The formation of each of these layers includes spin coating, casting, inkjet, vapor deposition, and printing, but vacuum vapor deposition is easy because a homogeneous layer is easily obtained and pinholes are difficult to generate. The method or spin coating method is particularly preferred. Further, different formation methods may be applied for each layer. When a vapor deposition method is employed for forming each of these layers, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C. and a degree of vacuum of 1 × 10 ⁻⁶ to 1 × 10 ⁻² Pa. It is desirable to appropriately select the respective conditions within the range of a deposition rate of 0.01 to 50 nm / second, a substrate temperature of −50 to 300 ° C., and a layer thickness of 0.1 to 5 μm.

After the light emitting unit-1 is formed as described above, the translucent intermediate electrode-1 is formed thereon by an appropriate forming method such as vapor deposition or sputtering. Next, the light-emitting unit-2, the translucent intermediate electrode-2, and the light-emitting unit-3 are laminated in the same manner, and the light-transmitting second electrode emits light while being insulated from the anode (anode) by the light-emitting unit group. The pattern is formed in a shape in which the terminal portion is drawn from the upper side of the delegate unit group to the periphery of the translucent substrate.

After the formation of the translucent second electrode, these are sealed with a translucent sealing substrate. At this time, the terminal portions of the anode (anode) and the cathode (cathode) are exposed, and sealing is performed on the light-transmitting substrate so as to cover at least the light emitting unit group.

In the manufacture of an organic EL element, for example, each electrode of the organic EL element is electrically connected to a light emitting element driving circuit unit or a touch detection circuit unit, and an electrical connection member that can be used at that time Although there is no restriction | limiting in particular if it is a member provided with electroconductivity, It is a preferable aspect that it is an anisotropic conductive film (ACF), an electroconductive paste, or a metal paste.

Examples of the anisotropic conductive film (ACF) include a layer having fine conductive particles having conductivity mixed with a thermosetting resin. The conductive particle-containing layer that can be used in the present invention is not particularly limited as long as it is a layer containing conductive particles as an anisotropic conductive member, and can be appropriately selected according to the purpose. There is no restriction | limiting in particular as electroconductive particle which can be used as an anisotropic conductive member, According to the objective, it can select suitably, For example, a metal particle, a metal covering resin particle, etc. are mentioned. Examples of commercially available ACFs include low-temperature curing ACFs that can also be applied to resin films, such as MF-331 (manufactured by Hitachi Chemical).

Examples of the metal particles include nickel, cobalt, silver, copper, gold, palladium, and the like. As the metal-coated resin particles, for example, the surface of the resin core is any one of nickel, copper, gold, and palladium. The metal paste may be a commercially available metal nanoparticle paste.

[Example of circuit of organic EL element of the present invention]
The organic EL device of the present invention is designed so that the polarities of the plurality of translucent intermediate electrodes are laminated from the translucent substrate side in the positive, negative repeating order, or the negative, positive repeating order. From the viewpoint of providing an organic electroluminescence device that is easy to control and can freely change the emission color, this is a preferred embodiment.

FIG. 3 is a schematic diagram showing an example of a circuit for driving an organic EL element having three light emitting units of the present invention. FIG. 3 is an example of a circuit in the case of the configuration of FIG. 1A.

The translucent second electrode 102, the translucent first electrode 101, and the translucent intermediate electrodes 104-1 and 104-2 can be independently applied with a voltage from the outside of the organic EL element 100. In the example shown in FIG. 3, the translucent first electrode 101, the translucent intermediate electrode 104-1, the translucent intermediate electrode 104-2, and the translucent second electrode 102 are formed of these electrodes. It is connected to a power supply circuit 200 that applies a voltage between arbitrary electrodes. Specifically, the translucent second electrode 102 can be connected to the cathode (cathode) terminal of the voltage source 210 via the first switch S1. The translucent intermediate electrode 104-2 can be connected to the cathode (cathode) terminal or the anode (anode) terminal of the voltage source 210 via the second switch S2. The translucent intermediate electrode 104-1 can be connected to the cathode (cathode) terminal or the anode (anode) terminal of the voltage source 210 via the third switch S3. The translucent first electrode 101 can be connected to the anode (anode) terminal of the voltage source 210 via the fourth switch S4.

The power supply circuit 200 controls the connection state of the first switch S1 to the fourth switch S4, thereby translucent first electrode 101, translucent intermediate electrode 104-1, translucent intermediate electrode 104-3, and translucent intermediate electrode 104-3. A voltage is applied between any of the optical second electrodes 102 to generate light in one or a plurality of light emitting layers of the organic EL element 100. That is, by selecting an electrode to which a voltage is applied by the power supply circuit 200, it is possible to output light of mixed colors in which light emission of a desired single color or a plurality of colors overlaps from the organic EL element 100.

Table 1 shows the relationship between the connection states of the first switch S1 to the fourth switch S4 of the power supply circuit 200 and the light emission states of the light emitting unit 103-1, the light emitting unit 103-2, and the light emitting unit 103-3 of the organic EL element 100. It is a table | surface which shows. In Table 1, “+” indicates that the first switch S1 to the fourth switch S4 are connected to the anode (anode) terminal of the voltage source 210, and “−” indicates that the first switch S1 to the fourth switch S4 are connected. The state connected to the cathode (cathode) terminal of the voltage source 210 is shown. “NC” indicates that the first switch S 1 to the fourth switch S 4 are open and not connected to the voltage source 210.

For example, in order to cause only the light emitting unit 103-3 to emit light, the first switch S1 is connected to the cathode terminal of the voltage source 210, and the second switch S2 is connected to the anode terminal of the voltage source 210. And the third switch S3 and the fourth switch S4 are opened. As a result, the translucent second electrode 102 becomes a cathode electrode and the translucent intermediate electrode 104-2 becomes an anode electrode, and light is emitted by recombination of holes and electrons in the light emitting unit 103-3.

In order to cause only the light emitting unit 103-2 to emit light, the second switch S2 is connected to the cathode terminal of the voltage source 210, the third switch S3 is connected to the anode terminal of the voltage source 210, and The first switch S1 and the fourth switch S4 are opened. As a result, the translucent intermediate electrode 104-2 becomes a cathode electrode and the translucent intermediate electrode 104-1 becomes an anode electrode, and light is emitted by recombination of holes and electrons in the light emitting unit 103-2.

In order to cause only the light emitting unit 103-1 to emit light, the third switch S 3 is connected to the cathode terminal of the voltage source 210, the fourth switch S 4 is connected to the anode terminal of the voltage source 210, and The first switch S1 and the second switch S2 are opened. As a result, the translucent intermediate electrode 104-1 becomes a cathode electrode and the translucent first electrode 101 becomes an anode electrode, and light is emitted by recombination of holes and electrons in the light emitting unit 103-1.

In order to cause the light emitting unit 103-3 and the light emitting unit 103-2 to emit light, the first switch S1 is connected to the cathode terminal of the voltage source 210, and the third switch S3 is connected to the anode terminal of the voltage source 210. And the second switch S2 and the fourth switch S4 are opened. As a result, the light-transmitting second electrode 102 becomes the cathode electrode and the light-transmitting intermediate electrode 104-1 becomes the anode electrode, and the light emitting unit 103-3 and the light emitting unit 103-2 emit light. Therefore, the mixed color light of the light emitting unit is output from the organic EL element 100.

In order to cause the light emitting unit 103-2 and the light emitting unit 103-1 to emit light, the second switch S2 is connected to the cathode terminal of the voltage source 210, and the fourth switch S4 is connected to the anode terminal of the voltage source 210. And the first switch S1 and the third switch S3 are opened. As a result, the light-transmitting intermediate electrode 104-2 becomes the cathode electrode and the light-transmitting first electrode 101 becomes the anode electrode, and the light emitting unit 103-2 and the light emitting unit 103-1 emit light. For this reason, light of mixed colors of the respective emitted lights is output from the organic EL element 100.

In order to cause the light emitting unit 103-3 and the light emitting unit 103-1 to emit light, the first switch S1 and the third switch S3 are connected to the cathode (cathode) terminal of the voltage source 210, and the second switch S2 and the fourth switch S4. Is connected to the anode terminal of the voltage source 210. As a result, the light-transmitting second electrode 102 becomes the cathode electrode and the light-transmitting intermediate electrode 104-2 becomes the anode electrode, and the light emitting unit 103-3 emits light. At the same time, the light-transmitting intermediate electrode 104-1 serves as a cathode electrode and the light-transmitting first electrode 101 serves as an anode electrode, and the light emitting unit 103-1 emits light. For this reason, light of mixed colors of the respective emitted lights is output from the organic EL element 100.

In order to make all of the light emitting unit 103-3, the light emitting unit 103-2, and the light emitting unit 103-1 emit light, the first switch S1 is connected to the cathode terminal of the voltage source 210, and the fourth switch S4 is connected to the voltage source. The second switch S2 and the third switch S3 are opened while being connected to the anode (anode) terminal 210. As a result, the light transmissive second electrode 102 becomes the cathode electrode and the light transmissive first electrode 101 becomes the anode electrode, and the light emitting unit 103-3, the light emitting unit 103-2, and the light emitting unit 103-1 emit light. For this reason, the organic EL element 100 outputs white light in which the respective emitted lights are mixed.

As described above, the organic EL element 100 shown in FIG. 3 includes any one of the light-transmitting second electrode 102, the light-transmitting first electrode 101, and the light-transmitting intermediate electrodes 104-1 and 104-2. By selecting and applying a voltage, light of any color can be output by generating light in any one or a plurality of layers of the light emitting unit 103-1, the light emitting unit 103-2, and the light emitting unit 103-3. The connection states of the first switch S1 to the fourth switch S4 are controlled by a control circuit (not shown) in order to output light of a desired color from the organic EL element 100.

≪Use of organic EL elements≫
The organic EL device of the present invention is a surface light emitter and is a double-sided light emitting type, and therefore can be used as various light emitting sources. For example, lighting devices such as home lighting and interior lighting, backlights for watches and liquid crystals, lighting for billboard advertisements, light sources for traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, The light source of an optical sensor can be used by taking advantage of the double-sided emission characteristics.

In particular, the organic EL element of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a type that directly recognizes a still image or a moving image. It may be used as a display device (display). In this case, with the recent increase in the size of lighting devices and displays, the light emitting surface may be enlarged by so-called tiling, in which light emitting panels provided with organic EL elements are joined together in a plane.

The drive method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. In addition, a color or full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

Hereinafter, the lighting device will be described.

[Lighting device-1]
The lighting device using the organic EL element of the present invention may be designed such that each organic EL element having the above-described configuration has a resonator structure. Examples of the purpose of use of the organic EL element configured as a resonator structure include, but are not limited to, a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processor, a light source of an optical sensor, and the like. . Moreover, you may use for the said use by making a laser oscillation.

Note that the material used for the organic EL element of the present invention can be applied to an organic EL element that emits white light (also referred to as a white organic EL element). For example, a plurality of light emitting materials can simultaneously emit a plurality of light emission colors to obtain white light emission by color mixing. As described above, the combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of red, green, and blue as described above, or use the relationship of complementary colors such as blue and yellow, blue green and orange, etc. It may be one containing the two emission maximum wavelengths.

In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and excitation of light from the light emitting materials. Any combination with a pigment material that emits light as light may be used, but in a white organic EL element, a combination of a plurality of light-emitting dopants may be used.

Such a white organic EL element is different from a configuration in which organic EL elements emitting each color are individually arranged in parallel to obtain white light emission, and the organic EL element itself emits white light. For this reason, a mask is not required for film formation of most layers constituting the element, and for example, an electrode film can be formed on one side by vapor deposition, casting, spin coating, ink jet, printing, etc., and productivity is improved. To do.

In addition, the light emitting material used for the light emitting layer of such a white organic EL element is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the light emitting material is adapted to a wavelength range corresponding to CF (color filter) characteristics. Any one of the metal complexes according to the present invention and known light-emitting materials may be selected and combined for whitening.

If the white organic EL element described above is used, it is possible to produce a lighting device that emits substantially white light.

[Lighting device-2]
Moreover, the organic EL element of this invention can be used also as an illuminating device which used multiple and made the light emission surface large area. In this case, the light emitting surface is enlarged by arranging a plurality of light emitting panels provided with organic EL elements on a transparent substrate (that is, tiling) on the support substrate. The support substrate may also serve as a sealing material, and each light emitting panel is tiled in a state where the organic EL element is sandwiched between the support substrate and the transparent substrate of the light emitting panel. An adhesive may be filled between the support substrate and the transparent substrate, thereby sealing the organic EL element. Note that the terminals of the translucent first electrode, the translucent intermediate electrode, and the translucent second electrode are exposed around the light emitting panel.

In the lighting device having such a configuration, the center of each light emitting panel is a light emitting region, and a non-light emitting region is generated between the light emitting panels. For this reason, a light extraction member for increasing the amount of light extracted from the non-light emitting area may be provided in the non-light emitting area of the light extraction surface. As the light extraction member, a light collecting sheet or a light diffusion sheet can be used.

When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE1931 color system at 1000 cd / m ² is X when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

Example 1
[Production of Organic EL Element 101]
<Translucent substrate>
A polyester film MELINEX ST504 (manufactured by Teijin DuPont Films Ltd.) having a width of 50 cm and a thickness of 125 μm was prepared as a translucent substrate. This polyester film is degassed for 3 hours by heating to 80 ° C. under a reduced pressure of 0.01 Torr.

On the polyester film, a polysilazane-containing coating solution was applied, and then a vacuum ultraviolet ray was applied to perform a modification treatment to provide a gas barrier layer, thereby producing a translucent flexible substrate.

(Preparation of polysilazane-containing coating solution)
Dibutyl ether solution containing 20% by mass of non-catalytic perhydropolysilazane (manufactured by AZ Electronic Materials, Aquamica (registered trademark) NN120-20) and amine catalyst (N, N, N ′, N′-tetramethyl-) Perhydropolysilazane 20 mass% dibutyl ether solution (AZ Electronic Materials Co., Ltd., Aquamica (registered trademark) NAX120-20) containing 5 mass% of 1,6-diaminohexane (TMDAH) 4: 1 In a solvent mixed so that the mass ratio of dibutyl ether and 2,2,4-trimethylpentane was 65:35, the coating solution was mixed so that the solid content of the coating solution was 5% by mass. Was diluted and prepared.

The coating solution obtained above was formed into a film with a thickness of 300 nm on the translucent substrate with a spin coater, left for 2 minutes, and then subjected to heat treatment for 1 minute on an 80 ° C. hot plate, A polysilazane coating film was formed.

After forming the polysilazane coating film, a vacuum ultraviolet ray irradiation treatment of 6000 mJ / cm ² was performed to form a gas barrier layer.

<Formation of translucent first electrode>
On the gas barrier layer, ITO (Indium Tin Oxide: ITO) having a thickness of 150 nm was formed by sputtering, and patterned by photolithography to form a transparent first electrode. . The pattern was such that the light emission area was 50 mm square.

<Formation of light emitting unit 1>
(Formation of hole transport layer)
First, a heating boat containing HT-1 as a hole transport injecting material is energized and heated, and a hole transport injecting layer serving as both a hole injecting layer and a hole transporting layer made of HT-1 is made transparent. The film was formed on the conductive first electrode. At this time, the pressure was reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa using a commercially available vacuum vapor deposition apparatus, and then vapor deposition was performed at a vapor deposition rate of 0.1 to 0.2 nm / second to obtain a layer thickness of 20 nm.

(Formation of the light emitting layer 1)
Next, each of the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent emission dopant A-3 (blue emission dopant: indicated as B in the table) was energized independently, and the host compound H- A light emitting layer containing 1 and phosphorescent light emitting dopant A-3 was formed on the hole transport injection layer. At this time, the energization of the heating boat was adjusted so that the vapor deposition rate was host compound H-1: phosphorescent dopant A-3 = 100: 6. The layer thickness was 30 nm.

(Hole blocking layer)
Next, the hole blocking layer made of BAlq is heated by energizing a heating boat containing BAlq ([Bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum]) as a hole blocking material. A film was formed on the light emitting layer. At this time, the deposition rate was 0.1 to 0.2 nm / second, and the layer thickness was 10 nm.

Thereafter, a heating boat containing ET-1 shown below as an electron transporting material and a heating boat containing potassium fluoride were energized independently to form an electron transporting layer containing ET-1 and potassium fluoride. A film was formed on the hole blocking layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was ET-1: potassium fluoride = 75: 25. The layer thickness was 30 nm.

Next, a heating boat containing potassium fluoride as an electron injection material was energized and heated to form an electron injection layer made of potassium fluoride on the electron transport layer. At this time, the deposition rate was 0.01 to 0.02 nm / second, and the layer thickness was 1 nm.

<Translucent intermediate electrode 1>
On the first light emitting unit, ITO (Indium Tin Oxide: ITO) having a thickness of 150 nm was formed by sputtering, and patterned by photolithography to form a light-transmitting intermediate electrode. The pattern was such that the light emission area was 50 mm square.

<Formation of light emitting unit 2>
The light emitting unit 2 was formed in the same manner as the light emitting unit 1 except that the light emitting layer 2 was formed as follows.

(Light emitting layer 2)
A heating boat containing the host compound H-1 and a heating boat containing the phosphorescent emission dopant A-1 (green emission dopant: indicated as G in the table) were energized independently, and the host material H-1 and A light emitting layer containing phosphorescent light emitting dopant A-3 was formed on the hole transport injection layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was host compound H-1: phosphorescent dopant A-1 = 100: 4. The layer thickness was 30 nm.

<Formation of translucent second electrode>
On the electron injection layer formed as described above, except for the portion that becomes the extraction electrode of the light transmissive first electrode, under a vacuum of 5 × 10 ⁻⁴ Pa, as a light transmissive second electrode forming material Using ITO, a mask pattern was formed by vapor deposition so as to have an extraction electrode so that the emission area was 50 mm square, and a light-transmitting second electrode having a thickness of 150 nm was laminated.

(Cutting)
As described above, each laminate including the light-transmitting second electrode was moved again to a nitrogen atmosphere, and cut to a prescribed size using an ultraviolet laser to produce an organic EL element.

(Electrode lead connection)
An anisotropic conductive film DP3232S9 manufactured by Sony Chemical & Information Device Co., Ltd. was used for the produced organic EL element, and a flexible printed circuit board (base film: polyimide 12.5 μm, rolled copper foil 18 μm, coverlay: polyimide 12 0.5 μm, surface-treated NiAu plating).

Crimping conditions: Crimping was performed at a temperature of 170 ° C. (ACF temperature 140 ° C. measured using a separate thermocouple), a pressure of 2 MPa, and 10 seconds.

<Sealing with translucent sealing substrate>
A thermosetting liquid adhesive (epoxy photo-curing adhesive: Luxtrac LC0629B manufactured by Toagosei Co., Ltd.) with a thickness of 30 μm was applied to the gas barrier layer side of the produced gas barrier translucent substrate, The adhesive surface of the sealing member and the organic EL element organic so that the end portions of the lead electrodes of the light-transmitting first electrode, light-transmitting intermediate electrode, and light-transmitting second electrode of the organic EL element are exposed. The functional layer surfaces were continuously overlapped and bonded by a dry laminating method to produce a sealed organic EL element 101 shown in Table 2.

The sealing process is performed under atmospheric pressure and in a nitrogen atmosphere with a moisture content of 1 ppm or less in accordance with JIS B 9920. The measured cleanliness is class 100, the dew point temperature is −80 ° C. or less, and the oxygen concentration is 0.8 ppm or less. At atmospheric pressure.

[Production of Organic EL Element 102]
In the production of the organic EL element 101, the following light emitting unit 3 is added, and the light transmitting substrate / light transmitting first electrode / light emitting unit 1 (B) / light transmitting intermediate electrode 1 / light emitting unit 2 (G) / light transmitting. The organic EL element 102 described in Table 2 was manufactured by laminating and sealing in the order of optical intermediate electrode 2 / light emitting unit 3 (R) / translucent second electrode / translucent sealing substrate.

<Formation of light emitting unit 3>
(Formation of hole transport layer)
A heating boat containing HT-1 as a hole transporting injection material is energized and heated, and a hole transporting injection layer made of HT-1 serving as both a hole injection layer and a hole transporting layer is made transparent. A film was formed on one electrode. At this time, the pressure was reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa using a commercially available vacuum vapor deposition apparatus, and then vapor deposition was performed at a vapor deposition rate of 0.1 to 0.2 nm / second to obtain a layer thickness of 20 nm.

(Formation of the light emitting layer 3)
Next, each of the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent light emitting dopant A-2 (red light emitting dopant: indicated as R in the table) was energized independently, and the host compound H- A light emitting layer containing 1 and phosphorescent light emitting dopant A-2 was formed on the hole transport injection layer. At this time, the energization of the heating boat was adjusted so that the vapor deposition rate was host compound H-1: phosphorescent dopant A-3 = 100: 6. The layer thickness was 30 nm.

The ratio a: b of the organic EL element 102 when the distance between the light emission unit 1 and the light emission center of the light emission unit 2 is a and the distance between the light emission unit 2 and the light emission center 3 is b is 1: 1 and equidistant from the light emission center of the light emitting unit disposed in the center.

[Production of Organic EL Element 103]
In the production of the organic EL element 102, the light emitting unit 1 is used instead of the light emitting unit 3, the light emitting unit 3 is used instead of the light emitting unit 2, and the light transmissive substrate / light transmissive first electrode / light emitting unit 1 ( B) / translucent intermediate electrode 1 / light emitting unit 3 (R) / translucent intermediate electrode 2 / light emitting unit 1 (B) / translucent second electrode / translucent sealing substrate in this order and sealing Thus, the organic EL element 103 shown in Table 2 was produced.

Ratio a when the distance between the light emitting unit 1 and the light emitting center of the light emitting unit 2 of the organic EL element 103 is a, and the distance between the light emitting unit 2 and the light emitting center of the upper light emitting unit 1 is b. : B was 1: 1 and was equidistant from the light emission center of the light emitting unit disposed in the center.

The emission center was obtained by measuring the emission distribution by the method described in paragraphs [0059] to [0069] of JP-A-2009-181829.

[Production of Organic EL Element 104]
In the production of the organic EL element 102, a translucent substrate / a translucent first electrode / a light emitting unit 2 (G) / a translucent intermediate electrode 1 / a light emitting unit 3 (R) / a translucent intermediate electrode 2 / a light emitting unit 2 (G) / translucent second electrode / translucent sealing substrate were laminated and sealed in this order to produce an organic EL element 104 shown in Table 2.

Ratio a when the distance between the light emitting unit 2 and the light emitting center of the light emitting unit 3 of the organic EL element 104 is a, and the distance between the light emitting unit 3 and the light emitting center of the upper light emitting unit 2 is b. : B was 1: 1 and was equidistant from the light emission center of the light emitting unit disposed in the center.

[Production of Organic EL Element 105]
In the production of the organic EL element 102, the following light emitting unit is added, and the light transmitting substrate / light transmitting first electrode / light emitting unit 1 (B) / light transmitting intermediate electrode 1 / light emitting unit 2 (G) / light transmitting. Intermediate electrode 2 / light emitting unit 3 (R) / light transmissive intermediate electrode 3 / light emitting unit 2 (G) / light transmissive intermediate electrode 4 / light emitting unit 1 (B) / light transmissive second electrode / light transmissive The organic EL element 105 shown in Table 2 was produced by stacking and sealing in the order of the sealing substrate.

The distances between the light emitting unit 1 and the light emitting unit 2 of the organic EL element 105 with respect to the light emitting unit 3 are a-1 and a-2, respectively, and the light emitting unit 2 on the upper layer side with respect to the light emitting unit 3 is used. The ratios a-1: b-1 and a-2: b-2 where the distance between the light emitting unit 1 and the light emission center of the light emitting unit 1 is b-1 and b-2 are 1: 1, respectively. All were equidistance with respect to the light emission center of the light emission unit to arrange | position.

[Production of Organic EL Element 106]
Using the translucent substrate with the gas barrier layer used in the production of the organic EL element 101, a translucent first electrode having a single layer structure was produced on the gas barrier layer as follows.

First, a translucent substrate with a gas barrier layer is set in a substrate holder, the compound ET-1 is placed in a resistance heating boat made of tantalum, and these substrate holder and heating boat are attached to the first vacuum chamber of the vacuum deposition apparatus. It was.

In this state, first, the first vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then heated by energizing a heating boat containing ET-1, and the layer thickness was deposited on the substrate at a deposition rate of 0.1 nm / second. An underlayer made of 25 nm ET-1 was provided.

Next, the translucent substrate formed up to the base layer was transferred to the second vacuum chamber while being vacuumed, and silver (Ag) was placed in a resistance heating boat made of tungsten, and attached to the vacuum chamber. Next, after the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, the resistance heating boat was energized and heated to form a single-layered translucent first electrode made of silver by resistance heating evaporation. The layer thickness of the formed transparent first electrode made of silver (Ag) was 10 nm.

In the production of the organic EL element 101, the translucent first electrode, the translucent intermediate electrode 1, and the translucent second electrode were formed in the same manner except that the electrodes were formed in the above-described configuration of the base layer and the silver layer, respectively. The organic EL element 106 shown in Table 2 was produced.

[Production of Organic EL Element 107]
In the production of the organic EL element 102, the light-transmitting first electrode, the light-transmitting intermediate electrode 1, the light-transmitting intermediate electrode 2, and the light-transmitting second electrode are formed with the above-described base layer and silver layer, respectively. The organic EL element 107 shown in Table 2 was produced in the same manner except that.

[Production of Organic EL Element 108]
In the production of the organic EL element 103, the transparent first electrode, the transparent intermediate electrode 1, the transparent intermediate electrode 2, and the transparent second electrode are formed with the above-described structure of the base layer and the silver layer, respectively. The organic EL element 108 shown in Table 2 was produced in the same manner except that.

[Production of Organic EL Element 109]
In the production of the organic EL element 104, the light-transmitting first electrode, the light-transmitting intermediate electrode 1, the light-transmitting intermediate electrode 2, and the light-transmitting second electrode are formed with the above-described base layer and silver layer, respectively. An organic EL element 109 shown in Table 2 was produced in the same manner except that.

[Production of Organic EL Element 110]
In the production of the organic EL element 108, the organic EL element 110 shown in Table 2 was produced in the same manner except that the light emitting unit 1, the light emitting unit 2, and the light emitting unit 3 were formed as follows.

<Formation of light emitting unit 1 (G / R)>
(Formation of hole transport layer)
A heating boat containing HT-1 as a hole transporting injection material is energized and heated, and a hole transporting injection layer made of HT-1 serving as both a hole injection layer and a hole transporting layer is made transparent. A film was formed on one electrode. At this time, the pressure was reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa using a commercially available vacuum vapor deposition apparatus, and then vapor deposition was performed at a vapor deposition rate of 0.1 to 0.2 nm / second to obtain a layer thickness of 20 nm.

(Formation of the light emitting layer 3)
Next, a heating boat containing the host compound H-1, a phosphorescence emission dopant A-1 (green emission dopant: indicated as G in the table) and a phosphorescence emission dopant A-2 (red emission dopant: R in the table) The heated boats were energized independently to form a yellow light emitting layer containing the host compound H-1 and phosphorescent light emitting dopants A-1 and A2 on the hole transport injection layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was host compound H-1: phosphorescent light emitting dopant A-1: phosphorescent light emitting dopant A-2 = 100: 4: 1. The layer thickness was 30 nm.

Thereafter, a heating boat containing ET-1 as an electron transport material and a heating boat containing potassium fluoride were energized independently, and the electron transport layer containing ET-1 and potassium fluoride was changed to a hole. A film was formed on the blocking layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was ET-1: potassium fluoride = 75: 25. The layer thickness was 30 nm.

<Formation of second light emitting unit>
The light emitting unit 1 (B) of the organic EL element 108 was used in the same manner.

<Formation of third light emitting unit>
The light emitting unit 1 (G / R) was used in the same manner.

[Production of Organic EL Element 111]
In the production of the organic EL element 105, the translucent first electrode, the translucent intermediate electrode 1, the translucent intermediate electrode 2, the translucent intermediate electrode 3, the translucent intermediate electrode 4, and the translucent second electrode are provided. The organic EL element 111 shown in Table 2 was produced in the same manner except that the electrodes were formed with the above-described foundation layer and silver layer, respectively.

[Production of Organic EL Element 112]
In the production of the organic EL element 108, the organic EL element 112 shown in Table 2 was produced in the same manner except that the translucent sealing substrate was changed to the translucent sealing substrate 2 described below.

(Translucent sealing substrate 2)
As the translucent sealing substrate 2, a biaxially stretched polyethylene naphthalate film (PEN film, thickness: 100 μm, width: 50 cm, manufactured by Teijin DuPont Films, trade name “Teonex Q65FA”) was used.

On the PEN film, the polysilazane-containing coating solution was applied, and then modified by irradiation with vacuum ultraviolet rays in the same manner to provide a gas barrier layer, thereby producing a flexible translucent sealing substrate.

[Preparation of organic EL element 113]
In the production of the organic EL element 108, the organic EL element 113 shown in Table 2 was produced in the same manner except that the translucent sealing substrate was changed to the translucent sealing substrate 3 described below.

(Translucent sealing substrate 3)
As the translucent sealing substrate 3, a biaxially stretched cycloolefin film (COP film, thickness: 100 μm, width: 50 cm, manufactured by Nippon Zeon Co., Ltd., trade name “Zeonor”) was used.

On the COP film, the polysilazane-containing coating solution was applied, and then modified by irradiation with vacuum ultraviolet rays in the same manner, and a gas barrier layer was provided to prepare a flexible translucent sealing substrate.

[Production of Organic EL Element 114]
In the production of the organic EL element 108, the same procedure was performed except that the light emitting unit 1a (B) having the following respective layer thicknesses was used instead of the light emitting unit 1 (B) stacked on the light emitting unit 3 (R). Thus, an organic EL element 114 shown in Table 2 was produced.

<Formation of light emitting unit 1a>
(Formation of hole transport layer)
A heating boat containing HT-1 as a hole transporting injection material is energized and heated, and a hole transporting injection layer made of HT-1 serving as both a hole injection layer and a hole transporting layer is made transparent. A film was formed on one electrode. At this time, the pressure was reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa using a commercially available vacuum vapor deposition apparatus, and then vapor deposition was performed at a vapor deposition rate of 0.1 to 0.2 nm / second to obtain a layer thickness of 30 nm.

(Formation of the light emitting layer 1a)
Next, each of the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent emission dopant A-3 (blue emission dopant: indicated as B in the table) was energized independently, and the host compound H- A blue light-emitting layer containing 1 and phosphorescent dopant A-3 was formed on the hole transport injection layer. At this time, the energization of the heating boat was adjusted so that the vapor deposition rate was host compound H-1: phosphorescent dopant A-3 = 100: 6. The layer thickness was 40 nm.

(Hole blocking layer)
Next, the hole blocking layer made of BAlq is heated by energizing a heating boat containing BAlq ([Bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum]) as a hole blocking material. A film was formed on the light emitting layer. At this time, the deposition rate was 0.1 to 0.2 nm / second, and the layer thickness was 15 nm.

Thereafter, a heating boat containing ET-1 shown below as an electron transporting material and a heating boat containing potassium fluoride were energized independently to form an electron transporting layer containing ET-1 and potassium fluoride. A film was formed on the hole blocking layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was ET-1: potassium fluoride = 75: 25. The layer thickness was 40 nm.

Next, a heating boat containing potassium fluoride as an electron injection material was energized and heated to form an electron injection layer made of potassium fluoride on the electron transport layer. At this time, the deposition rate was 0.01 to 0.02 nm / second, and the layer thickness was 2 nm.

Ratio a when the distance between the light emitting unit 1 and the light emitting center of the light emitting unit 2 of the organic EL element 114 is a, and the distance between the light emitting unit 2 and the light emitting center of the upper light emitting unit 1a is b. : B was a ≠ b because the layer thickness was changed, and was not equidistant from the light emission center of the light emitting unit disposed in the center.

[Production of Organic EL Element 115]
In the production of the organic EL element 111, instead of the light emitting unit 2 (G) and the light emitting unit 1 (B) stacked on the light emitting unit 3 (R), the light emitting unit 2a (G) in which the following respective layer thicknesses are changed. And the organic EL element 115 of Table 2 was produced similarly except having used the formed light emitting unit 1a (B).

<Formation of light emitting unit 2a (G)>
(Formation of hole transport layer)
A heating boat containing HT-1 as a hole transporting injection material is energized and heated, and a hole transporting injection layer made of HT-1 serving as both a hole injection layer and a hole transporting layer is made transparent. A film was formed on one electrode. At this time, the pressure was reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa using a commercially available vacuum vapor deposition apparatus, and then vapor deposition was performed at a vapor deposition rate of 0.1 to 0.2 nm / second to obtain a layer thickness of 30 nm.

(Formation of the light emitting layer 2a)
Next, each of the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent light emitting dopant A-1 (green light emitting dopant: indicated as G in the table) was energized independently, and the host compound H- A green light-emitting layer containing 1 and phosphorescent dopant A-1 was deposited on the hole transport injection layer. At this time, the energization of the heating boat was adjusted so that the vapor deposition rate was host compound H-1: phosphorescent dopant A-3 = 100: 6. The layer thickness was 40 nm.

The distance between the light emitting unit 1 and the light emitting center of the light emitting unit 2 with respect to the light emitting unit 3 of the organic EL element 115 is c-1 and c-2, respectively, and the light emitting unit 2a on the upper layer side with respect to the light emitting unit 3 is used. When the distance between the light emitting unit 1a and the light emitting center of the light emitting unit 1a is d-2 and d-1, c-1 ≠ d-1 and c-2 ≠ d-2, and the light emitting center of the light emitting unit disposed in the center Are not equidistant.

The following evaluation was performed on the produced organic EL elements 101 to 115.

≪Evaluation≫
[Evaluation of transparency]
For each of the organic EL devices prepared above, after being conditioned in an air-conditioned room at 23 ° C. and 55% RH for 24 hours, the non-light-emitting transparency was measured according to JIS K-7136 as a haze meter (NDH2000 type, Nippon Denshoku). Kogyo Co., Ltd.) was used to measure and evaluate the total light transmittance.

◎: Transmittance is 75% or more ○: Transmittance is 65% or more and less than 75% Δ: Transmittance is 55% or more and less than 65% ×: Transmittance is less than 55% [Evaluation of difference in luminance and chromaticity]
Measuring instrument: Konica Minolta 2D color luminance meter CA-2500
Data analysis software: Konica Minolta Co., Ltd. data management software CA-S25w
Measurement conditions: The distance from the substrate is the light (Lx) emitted in the normal direction from the translucent substrate side to the substrate by causing each organic EL element to emit light in an environment of 23 ° C. and 55% RH. The luminance and chromaticity were measured with the above measuring instrument at 5 cm. Similarly, the luminance and chromaticity of light emitted from the light-transmitting sealing substrate side in the normal direction with respect to the substrate (Ly) at a distance of 5 cm from the substrate were measured with the measuring instrument.

Next, the measured luminance and chromaticity values were used as data by the above data analysis software.

From the obtained Lx and Ly luminance and chromaticity data, the smaller value was divided by the larger value to obtain a ratio (%), and the difference was verified.

The structure and evaluation results of the organic EL element are shown in Table 2 below.

From Table 2, it can be seen that the organic EL device of the present invention is an organic EL device having high transparency, small deviation in luminance and chromaticity when emitting light on both sides, and capable of emitting light uniformly from both sides. In particular, it has been found that by arranging light emitting units having light emission centers that are equidistant from the light emission center in the central portion in a symmetrical manner, their deviation is small.

Regarding the transparency, it can be seen that the use of a silver electrode can be made thinner than the use of ITO as a translucent electrode, and thus the transparency is excellent.

The organic EL element of the present invention can freely change the emission color by selecting the light emitting unit. However, like the organic EL element 110, a yellow light emitting layer having a complementary color relationship with the blue light emitting layer is provided. As a result, it was found that white light emission was obtained, and the structure of the organic EL element suitable for illumination use and a transparent element were obtained.

Furthermore, like the organic EL elements 105, 111, and 115, by arranging B, G, and R light emitting units symmetrically, a full color light emitting element capable of emitting light on both sides with uniform luminance and chromaticity can be obtained.

The organic electroluminescence device of the present invention is a double-sided light emitting type, is transparent when not emitting light, emits light with uniform brightness and chromaticity from both sides when emitting light, and can freely change the emission color. Therefore, it can be used as various light emission sources. For example, lighting devices such as home lighting and interior lighting, backlights for watches and liquid crystals, lighting for billboard advertisements, light sources for traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, It is suitable for applications that make use of the characteristics of a double-sided light emission type, such as a light source of an optical sensor.

100 Organic EL element 101 Translucent first electrode 102 Translucent second electrode (counter electrode)
103-1, 103-2, 103-3, 103-4, 103-5 Light-emitting unit 104-1, 104-2, 104-3, 104-4 Translucent intermediate electrode 105 Translucent substrate 106 Translucent Sealing substrate h Light emission (emission center)
200 Power supply circuit 210 Voltage source

Claims

At least a translucent substrate, a translucent first electrode, an odd number of three or more light emitting units, a plurality of translucent intermediate electrodes arranged between the light emitting units, a translucent second electrode, and a translucent seal An organic electroluminescence device in which substrates are stacked in this order and sealed by the translucent sealing substrate, wherein the odd number of the three or more light emitting units are blue, green and red, or a mixture thereof An organic electro that uses at least two types of light emitting units selected from light emitting units having a light emitting color, and has light emitting units of different light emitting colors arranged at symmetrical positions with respect to the light emitting unit arranged in the center. Luminescence element.
2. The light emission centers inside the light emitting units at the symmetrical positions of the three or more odd number of light emitting units are equidistant from the light emission centers of the light emitting units arranged at the center, respectively. The organic electroluminescent element of description.
3. The organic electroluminescence device according to claim 1, wherein the translucent substrate and the translucent sealing substrate are both flexible substrates and are made of the same material. .
4. The polarity of the plurality of translucent intermediate electrodes is positive and negative repeating order from the translucent substrate side, or negative and positive repeating order. 5. The organic electroluminescent element according to claim 1.
The said translucent 1st electrode, the said translucent intermediate electrode, and the said translucent 2nd electrode are all the transparent electrodes which have silver as a main component, From Claim 1 to Claim 4 characterized by the above-mentioned. The organic electroluminescent element as described in any one.