JP5102666B2 - ORGANIC ELECTROLUMINESCENT ELEMENT AND LIGHTING DEVICE - Google Patents

Description

  The present invention relates to an organic electroluminescence element used for a light source of a flat panel display, a backlight for a liquid crystal display, an illumination device, and the like, and particularly relates to a light source particularly suitable for illumination use.

  The light emission color of the organic electroluminescence element is determined by the light-emitting substance contained in the light-emitting layer, and currently used light-emitting materials are monochromatic light-emitting materials such as blue, green, and red.

  However, for example, when an organic electroluminescence element is applied to a light source for illumination, it is preferable that the light emission of the organic electroluminescence element includes a plurality of emission colors. The organic electroluminescence element preferably emits white light. Here, the white light emission is light emission including almost one light having a wavelength in the visible light region, and is obtained by, for example, a color mixture of two colors having a complementary color relationship of light blue and orange.

  By the way, it is also preferable that the illumination light source has high color rendering properties. The color rendering properties of the light source are evaluated by, for example, an average color rendering index (Ra). In order to obtain a high average color rendering index (for example, Ra ≧ 80), it is preferable that the light emission from the light source includes light emission components of a plurality of wavelengths, and particularly, light emission components of three or more colors are included. Is preferred.

As an organic electroluminescence element containing such three color light emitting components, one disclosed in Patent Document 1 has been reported. This Patent Document 1 discloses an organic electroluminescence element in which a light emitting layer having a light emission maximum is laminated in each of a blue region (440 to 480 nm), a green region (510 to 540 nm), and a red region (600 to 640 nm). Has been.
JP 2006-287154 A

  However, the chromaticity of the emission color of the organic electroluminescent element disclosed in Patent Document 1 does not reach the chromaticity range of each light source color (bulb color, warm white, white, day white, daylight color) defined in JIS Z9112. In addition, when the element design is made such that the emission color is divided into the respective light source colors, there is a problem that the color rendering property of the emission color is lowered. Here, in particular, as a light source for illumination, it is desirable that a high average color rendering index be obtained by using the same light emitting material regardless of the light source color defined in JIS Z9112. .

  For this reason, the conventional organic electroluminescent element did not have sufficient characteristics as a light source for illumination.

  The present invention has been made in view of the above points, and has an organic electroluminescence element that is high in both whiteness and color rendering, and particularly suitable for a light source for illumination, and an illumination device equipped with the organic electroluminescence. The purpose is to provide.

  The organic electroluminescence device A according to the present invention has a structure in which a plurality of light emitting layers 3 are laminated between an anode 1 and a cathode 2. The plurality of light emitting layers 3 include a blue region light emitting layer 3a having a maximum light emission wavelength in a wavelength region of 450 to 470 nm, a yellow region light emitting layer 3b having a maximum light emission wavelength in a wavelength region of 550 to 570 nm, and 600 to 620 nm. And a red region light emitting layer 3c having a maximum emission wavelength in the wavelength region.

  For this reason, the whiteness of the luminescent color of the organic electroluminescence element A is improved, and the chromaticity of the luminescent color of each light source color (bulb color, warm white, white, daylight white, daylight color) specified by JIS Z9112 is improved. It is possible to reach the chromaticity range. Further, the color rendering properties of the emitted color are also improved, and even when the chromaticity of the emitted color reaches the chromaticity range of each light source color defined in JIS Z9112, for example, the average color rendering index is 80 or more. It is possible to emit light having such a high color rendering property.

  The average color rendering index of the entire luminescent color of the organic electroluminescence element A is preferably 80 or more. In this case, the color rendering properties of the organic electroluminescence element are particularly excellent.

  In particular, among the blue region light emitting layer 3a, yellow region light emitting layer 3b, and red region light emitting layer 3c, the red region light emitting layer 3c has the highest light emission intensity, the blue region light emitting layer 3a has the lowest light emission intensity, The emission color is preferably classified into a light bulb color or warm white color defined in JIS Z9112.

  Of the blue region light emitting layer 3a, yellow region light emitting layer 3b, and red region light emitting layer 3c, the blue region light emitting layer 3a has the highest light emission intensity, the red region light emitting layer 3c has the lowest light emission intensity, and the whole Is preferably divided into daylight white or daylight color as defined in JIS Z9112.

  Moreover, the illuminating device which concerns on this invention comprises the above organic electroluminescent elements A, It is characterized by the above-mentioned. Thereby, an illuminating device capable of emitting light having high whiteness and color rendering properties while using the organic electroluminescence element as a light source is obtained.

  According to the present invention, both the whiteness and color rendering of the emission color of the organic electroluminescence element are improved, and it can be used as a light source for a flat panel display, a backlight for a liquid crystal display, an illumination device, etc. An organic electroluminescence element suitable for a light source can be obtained. In addition, according to the present invention, an illuminating device capable of emitting light having high whiteness and color rendering properties while using an organic electroluminescence element as a light source can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described.

  An example of the structure of the organic electroluminescence element A is shown in FIG. In the example shown in the drawing, a plurality of light emitting layers 3 are laminated in the electrode stacking direction between the electrode to be the anode 1 and the electrode to be the cathode 2. Further, one electrode (anode 1) is laminated on the surface of the transparent substrate 5. The anode 1 is formed as a light transmissive electrode, and the cathode 2 is formed as a light reflective electrode.

  In the illustrated form, as the light emitting layer 3, a blue region light emitting layer 3a having a maximum light emission wavelength in a wavelength region of 450 to 470 nm, a yellow region light emitting layer 3b having a maximum light emission wavelength in a wavelength region of 550 to 570 nm, and 600 to 620 nm. The red region light emitting layer 3c having the maximum light emission wavelength is provided in the wavelength region. The number of stacked light emitting layers 3 is not particularly limited as long as the three types of light emitting layers 3a, 3b, and 3c are included. However, increasing the number of layers increases the difficulty of designing optical and electrical elements. , It is preferable to be within 5 layers. Similarly to a general organic electroluminescence element A, a hole injection layer, a hole transport layer 6, an electron transport layer 7, an electron injection layer, and the like may be provided between the light emitting layer 3 and the anode 1 or the cathode 2. .

As each light emitting layer 3, the thing formed with the organic material doped with the luminescent organic substance is mentioned. As the light emitting organic materials used for the blue region light emitting layer 3a, the yellow region light emitting layer 3b, and the red region light emitting layer 3c, the light emitting organic materials having the maximum light emission wavelength in the predetermined wavelength region are the light emitting layers 3 respectively. Each is appropriately selected. As the luminescent organic material used for the blue region luminescent layer 3a,
Specifically, as the light emitting organic material used for the blue region light emitting layer 3a, TBPe having the structure shown in the following [Chemical Formula 1], FIrpic having the structure shown in the following [Chemical Formula 2], 3] and the like.

  Further, as the light emitting organic material used for the yellow region light emitting layer 3b, rubrene, Bt2Ir (acac), (bis (2-phenylbenzothiazolate-N, C ′) iridium (acetylacetonate) ) And the like.

  Moreover, as a luminescent organic substance used for the red region light emitting layer 3c, Btp2Ir (acac) having a structure shown in the following [Chemical Formula 4], trade name DCJTB manufactured by Eastman Kodak Co., And Pq2Ir (acac) having the structure shown.

  When the light emitting organic material as described above is used, as the host material used for each light emitting layer 3, either an electron transporting material or a hole transporting material can be used. A mixture of an electron transporting material and a hole transporting material can also be used. In addition, a concentration gradient of the host material may be formed in the light emitting layer 3. For example, the ratio of the hole transporting material increases on the anode 1 side of the light emitting layer 3 and the electron transport on the cathode 2 side of the light emitting layer 3. The light emitting layer 3 may be formed so that the ratio of the conductive material increases.

  The electron transporting material and the hole transporting material used as the host material are not particularly limited. For example, from a material corresponding to a material constituting the hole transporting layer 6 and a material constituting the electron transporting layer 7 described later. Those appropriately selected are used.

In the organic electroluminescent element A, the light emitting layers 3 adjacent to each other may be in direct contact with each other, but it is preferable that the intermediate layer 4 is interposed between the light emitting layers 3. As the intermediate layer 4, for example, a layer forming an equipotential surface or a charge generation layer is formed. Examples of the material of the equipotential surface forming layer or charge generation layer include metal thin films such as Ag, Au, and Al; metal oxides such as vanadium oxide, molybdenum oxide, rhenium oxide, and tungsten oxide; ITO, IZO, AZO, GZO, ATO, SnO ₂ or other transparent conductive film; a laminate of so-called n-type semiconductor and p-type semiconductor; a laminate of a metal thin film or transparent conductive film and one or both of an n-type semiconductor and a p-type semiconductor; n-type Examples thereof include a mixture of a semiconductor and a p-type semiconductor; a mixture of one or both of an n-type semiconductor and a p-type semiconductor and a metal. The n-type semiconductor and the p-type semiconductor are not particularly limited and those selected as necessary are used. At this time, the n-type semiconductor or the p-type semiconductor may be either an inorganic material or an organic material. In addition, the n-type semiconductor and the p-type semiconductor are a mixture of an organic material and a metal; a combination of an organic material and a metal oxide; a combination of an organic material and an organic acceptor / donor material or an inorganic acceptor / donor material. It may be.

  In the organic electroluminescence element A configured as described above, since the plurality of light emitting layers 3 are laminated, high luminance light emission is possible.

  Moreover, since the organic electroluminescent element A according to the present invention includes the blue region light emitting layer 3a, the yellow region light emitting layer 3b, and the red region light emitting layer 3c as described above, the whiteness of the light emission color of the organic electroluminescent element A is high. This makes it possible to design an element in which the chromaticity of the emitted color reaches the chromaticity range of each light source color (bulb color, warm white, white, daylight white, daylight color) defined in JIS Z9112. At this time, it is possible to design an element such that the chromaticity of the emission color of the organic electroluminescent element A corresponds to one of the light source color categories.

  Moreover, when the organic electroluminescence element A has the above-described configuration, the color rendering property of the emission color of the organic electroluminescence element A is also improved. At this time, the element design is such that the average color rendering index of the light emission color of the organic electroluminescence element A is 80 or more, regardless of which of the light source color categories the light emission color of the organic electroluminescence element A corresponds to. Is possible.

  Adjustment of the chromaticity of the emission color so that the emission color of the organic electroluminescence element A corresponds to any one of a bulb color, warm white, white, daylight white, and daylight, and the emission color of the organic electroluminescence element A For adjusting the average color rendering index so that the average color rendering index is 80 or more, for example, the film thickness of each light emitting layer 3 is adjusted, and the doping concentration of the light emitting dopant (light emitting organic material) in each light emitting layer 3 is adjusted. It is achieved by adjusting, selecting an appropriate material as a material constituting each light emitting layer 3, performing an appropriate optical design (particularly, adjusting a dimension between the light emitting layer 3 and the cathode 2), etc. .

  As a specific example of the element design of the organic electroluminescence element A, the red region light emitting layer 3c has the highest light emission intensity among the blue region light emitting layer 3a, the yellow region light emitting layer 3b, and the red region light emitting layer 3c. There is an element design in which the light emission intensity of the area light emitting layer 3a is the lowest, and the entire light emission color is further classified into a light bulb color or warm white as defined in JIS Z9112. In this case, the light emission color of the organic electroluminescent element A becomes a light bulb color or warm white required as the color tone of illumination, and the color rendering property is excellent.

  As another specific example of the element design of the organic electroluminescence element A, the blue region light emitting layer 3a has the highest light emission intensity among the blue region light emitting layer 3a, the yellow region light emitting layer 3b and the red region light emitting layer 3c. In addition, there is an element design in which the light emission intensity of the red region light emitting layer 3c is the lowest and the entire light emission color is further divided into daylight white color or daylight color defined in JIS Z9112. In this case, the light emission color of the organic electroluminescent element A becomes the day white or daylight color required as the color tone of the illumination, and the color rendering property is excellent.

  In addition to the element design exemplified above, among the blue region light emitting layer 3a, yellow region light emitting layer 3b and red region light emitting layer 3c, for example, the light emission intensity of the yellow region light emitting layer 3b is the lowest, and further Of the configuration in which the entire emission color is classified into the light bulb color or warm white defined in JIS Z9112, the red emission layer among the blue emission layer 3a, yellow emission layer 3b and red emission layer 3c. In addition to the highest emission intensity of 3c, it is possible to design an appropriate element such as a configuration in which the entire emission color is classified into white, day white, or daylight color as defined in JIS Z9112.

  Here, the light emission intensity of each light emitting layer 4 is adjusted by adjusting the film thickness of each light emitting layer 3, adjusting the doping concentration of the light emitting dopant (light emitting organic substance) in each light emitting layer 3, and each light emission. This is done by selecting an appropriate material as the material constituting the layer 3.

  Of the members constituting the organic electroluminescence element A, members other than the light emitting layer 3, that is, members such as the substrate 5, the anode 1, and the cathode 2 that hold the stacked elements are conventionally used. The member can be employed as it is.

  For example, the substrate 5 has optical transparency when light is emitted through the substrate 5. In this case, examples of the substrate 5 include a colorless and transparent substrate, a transparent substrate having some coloring, and a ground glass-like substrate. Specific examples of the substrate 5 include, for example, a transparent glass plate such as soda lime glass and non-alkali glass, a plastic film produced by an arbitrary method from a resin such as polyester, polyolefin, polyamide, or epoxy, or a fluorine resin. And plastic plates. Furthermore, the light diffusion effect is obtained by containing particles, powder, bubbles, or the like having a refractive index different from that of the base material in the base material of the substrate 5 or by imparting an appropriate shape to the surface of the substrate 5. The board | substrate 5 to which was provided is also mentioned. Further, when light is emitted without passing through the substrate 5, the substrate 5 does not necessarily have a light transmitting property. In this case, any substrate can be used as long as the light emission characteristics, life characteristics, etc. of the element are not impaired. 5 can be used. In particular, the substrate 5 having high thermal conductivity can be used in order to reduce the temperature rise due to heat generation of the element during energization.

The anode 1 is an electrode that exhibits a function of injecting holes into the light emitting layer 3. The anode 1 is preferably formed from an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function. At this time, the work function of the anode 1 is particularly preferably 4 eV or more. Examples of the material of the anode 1 include metals such as gold; CuI, ITO (indium-tin oxide), SnO ₂ , ZnO, IZO (indium-zinc oxide), etc .; conductive properties such as PEDOT and polyaniline. Suitable conductive light-transmitting materials such as polymer; conductive polymer doped with any acceptor and the like; carbon nanotubes and the like.

  The anode 1 is produced, for example, by forming the electrode material as described above into a thin film on the surface of the substrate 5 by a method such as vacuum deposition, sputtering, or coating. In addition, in order for light emitted from the light emitting layer 3 to be transmitted to the outside through the anode 1, the light transmittance of the anode 1 is preferably 70% or more. Furthermore, the sheet resistance of the anode 1 is preferably several hundred Ω / □ or less, and particularly preferably the sheet resistance is 100 Ω / □ or less. Here, in order for the characteristics such as light transmittance and sheet resistance of the anode 1 to be controlled as described above, the film thickness of the anode 1 varies depending on the material constituting the anode 1, but is set to 500 nm or less. In particular, it is preferably set in the range of 10 to 200 nm.

The cathode 2 is an electrode that exhibits a function of injecting electrons into the light emitting layer 3. The cathode 2 is preferably formed from an electrode material made of a metal, an alloy, an electrically conductive compound, and a mixture thereof having a low work function. In particular, the work function of the cathode 2 is preferably 5 eV or less. Examples of the electrode material of the cathode 2 include alkali metals, alkali metal halides, alkali metal oxides, alkaline earth metals, and the like, and alloys of the above metals with other metals. Specific examples of the electrode material include sodium, sodium-potassium alloy, lithium, magnesium, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, and Al / LiF mixture. As the electrode material, aluminum, Al / Al ₂ O ₃ mixture or the like can also be used.

  Further, the cathode 2 may be formed by stacking one or more electrode materials on a base formed from an alkali metal oxide, an alkali metal halide, a metal oxide, or the like. Specific examples of the structure of the cathode 2 include, for example, an alkali metal / Al laminate, an alkali metal halide / alkaline earth metal / Al laminate, an alkali metal oxide / Al laminate, and the like. .

  Further, when the cathode 2 is a transparent electrode typified by ITO, IZO, etc., light can be extracted from the cathode 2 side.

  The organic layer in contact with the cathode 2 in the device may be doped with an alkali metal such as lithium, sodium, cesium, or calcium, or an alkaline earth metal.

  The cathode 2 is produced, for example, by forming the electrode material as described above into a thin film by a method such as a vacuum deposition method or a sputtering method. Moreover, when the light emission in the light emitting layer 3 is taken out from the anode 1 side, the light transmittance of the cathode 2 is preferably 10% or less. Moreover, when the light emission in the light emitting layer 3 is taken out from the cathode 2 side (including the case where the light emission is taken out from both the anode 1 and the cathode 2), the light transmittance of the cathode 2 is preferably 70% or more. In this case, the film thickness of the cathode 2 is appropriately set according to the material constituting the cathode 2 in order to control characteristics such as light transmittance of the cathode 2, but is usually 500 nm or less, preferably in the range of 100 to 200 nm. It is preferable that

  The element configuration of the organic electroluminescence element A of the present invention can be arbitrarily configured unless it is contrary to the gist of the present invention. For example, as described above, layers such as a hole injection layer, a hole transport layer 6, an electron transport layer 7, and an electron injection layer are appropriately provided as necessary.

  The material constituting the hole transporting layer 6 is selected from the group of compounds having hole transporting properties. However, the material has electron donating properties and is stable even when radically cationized by electron donation. preferable. Examples of this type of compound include 4,4′-bis [N- (naphthyl) -N-phenyl-amino] biphenyl (α-NPD), N, N′-bis (3-methylphenyl)-(1 , 1′-biphenyl) -4,4′-diamine (TPD), 2-TNATA, 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (MTDATA) 4,4′-N, N′-dicarbazole biphenyl (CBP), spiro-NPD, spiro-TPD, spiro-TAD, TNB and the like, and triarylamine compounds, amine compounds containing carbazole groups And amine compounds containing a fluorene derivative, but are not limited thereto, and any generally known hole transporting material may be used.

  The material constituting the electron transport layer 7 is selected from the group of compounds having an electron transport property, but has a hole donating property and is stable even when radical anionization is performed by hole donation. It is preferable that Examples of this type of compound include metal complexes known as electron transport materials such as Alq3, and compounds having a heterocycle such as phenanthroline derivatives, pyridine derivatives, tetrazine derivatives, oxadiazole derivatives, etc. Instead, any commonly known electron transport material is used.

  An appropriate configuration existing in the past can be adopted for an illumination device including such an organic electroluminescence A as a light source.

  Hereinafter, the present invention will be described in more detail by giving specific examples according to the present invention.

Example 1
A 0.7 mm-thick non-alkali glass substrate 5 on which an ITO film (anode 1) having a thickness of 150 nm, a width of 5 mm, and a sheet resistance of about 12Ω / □ was prepared. The substrate 5 provided with the anode 1 was subjected to ultrasonic cleaning for 10 minutes each with a detergent, ion-exchanged water, and acetone, then steam-washed with IPA (isopropyl alcohol), dried, and further subjected to UV / O ₃ treatment.

Next, the substrate 5 provided with the anode 1 is set in a vacuum deposition apparatus, and 4,4′-bis [N- (naphthyl) -N is formed on the anode 1 under a reduced pressure atmosphere of 1 × 10 ⁻⁴ Pa or less. -Phenyl-amino] biphenyl (α-NPD) was deposited to a thickness of 40 nm to form a hole transport layer 6.

  Next, a layer obtained by co-depositing 7% by mass of Btp2Ir on 4,4′-N, N′-dicarbazole biphenyl (CBP) is deposited on the hole transport layer 6 to a thickness of 10 nm, and the red region light emitting layer 3c (Maximum emission wavelength 620 nm) was formed.

  Next, bathocuproin (BCP) was vapor-deposited alone to a thickness of 20 nm on the red region light emitting layer 3c to form the electron transport layer 7.

  Next, an alloy film having a molar ratio of BCP and Cs of 1: 1 is deposited on the electron transport layer 7 to a thickness of 5 nm, and then a deposited film of IZO (indium zinc oxide) is deposited to a thickness of 10 nm. Intermediate layer 4 was formed.

  Next, α-NPD was deposited on the intermediate layer 4 to a thickness of 60 nm to form a hole transport layer 6.

  Next, a layer obtained by co-depositing 5 mass% of TBPe on CBP was deposited on the hole transport layer 6 to a thickness of 20 nm to form a blue region light emitting layer 3a (maximum light emission wavelength of 460 nm).

  Next, a layer in which 5% by mass of rubrene was co-evaporated on Alq3 was deposited on the blue region light emitting layer 3a with a film thickness of 10 nm to form a yellow region light emitting layer 3b (maximum light emission wavelength of 555 nm).

  Next, on this yellow area light emitting layer 3b, Alq3 was vapor-deposited alone by 40 nm, and then LiF was vapor-deposited to a thickness of 1 nm to form the electron transport layer 7.

  Next, on the electron transport layer 7, aluminum was vapor-deposited at a thickness of 80 nm at a vapor deposition rate of 0.4 nm / s to form the cathode 2.

  Through the above steps, an organic electroluminescent element A having a structure in which the red region light emitting layer 3c, the blue region light emitting layer 3a, and the yellow region light emitting layer 3b are laminated is obtained.

(Examples 2-9)
In Example 1, the thicknesses of the red region light emitting layer 3c, the blue region light emitting layer 3a, and the yellow region light emitting layer 3b were changed as shown in Table 1. Other conditions were the same as in Example 1, and an organic electroluminescent device A having a structure in which a red region light emitting layer 3c, a blue region light emitting layer 3a, and a yellow region light emitting layer 3b were laminated was obtained.

(Comparative Examples 1-5)
In the said Examples 1-5, it replaced with the yellow area | region light emitting layer 3b, and formed the light emitting layer 3 (green area light emitting layer 3) with the maximum light emission wavelength of 525 nm.

  In forming the green region light emitting layer 3, after the step of forming the blue region light emitting layer 3a in Examples 1 to 5 above, C545T (10- (2- Benzothiazolyl) -1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H, 11H- [1] benzo-pyrano [6,7,8-ij] quinolidin-11-one ) Was co-deposited at a film thickness shown in Table 1 to form a green light emitting layer 3.

  Other conditions were the same as in Example 1, and an organic electroluminescent device A having a structure in which the red region light emitting layer 3c, the blue region light emitting layer 3a, and the green region light emitting layer 3 were laminated was obtained.

(Evaluation)
By connecting a power source (KEITHLEY2400) to the organic electroluminescent element A obtained in each example and comparative example, and applying a constant current of 10 mA / cm ² to the organic electroluminescent element A, the organic electroluminescent element A was driven. At this time, the emission spectrum of the light emitted from the organic electroluminescence element A toward the front direction was measured with a multi-channel analyzer (“PMA-11” manufactured by Hamamatsu Photonics). Based on this measurement result, the luminescent color of the organic electroluminescent element A was evaluated by the chromaticity coordinates of the CIE color system. Moreover, based on this chromaticity coordinate, the light emission color of the organic electroluminescent element A was classified into the light source color prescribed | regulated to JISZ9112. Moreover, the average color rendering index (Ra) of the luminescent color of the organic electroluminescence element A was derived by a method defined in JIS Z8726.

  Moreover, about Example 1, 2, 4-9, about the light emission from the organic electroluminescent element A, deviation (DELTA) uv from a black-body locus | trajectory was derived | led-out based on prescription | regulation of JISZ8725.

  Moreover, about Example 1, 2, 4-9, in the emission spectrum of the organic electroluminescent element A, the maximum wavelength (460 nm) resulting from the blue region light emitting layer 3a and the maximum wavelength (620 nm) resulting from the red region light emitting layer 3c. ), And the ratio of each intensity of the maximum wavelength (555 nm) due to the yellow region light emitting layer 3b.

  The above results are shown in Tables 1 and 2.

  As described above, in the case of Comparative Examples 1 to 5, although the emission color of the organic electroluminescence element A was classified into the light source color defined in JIS Z9112, the value of the average color rendering index was not sufficient.

  On the other hand, in Examples 1-9, the light emission color of the organic electroluminescent element A was classified into the light source color prescribed | regulated by JISZ9112, and the value of the average color rendering index was high.

  In Examples 1 and 2, the blue region light emitting layer 3a has the highest light emission intensity among the light emitting layers 3, the red region light emitting layer 3c has the lowest light emission intensity, and the light emission color is divided into daylight white or daylight color. . In Examples 4 and 5, the red region light emitting layer 3c has the highest light emission intensity among the light emitting layers 3, the blue region light emitting layer 3a has the lowest light emission intensity, and the light emission color is classified into a light bulb color or warm white. The In these Examples 1, 2, 4, and 5, the deviation from the black body locus is small as compared with Examples 6 to 9 having the same emission color. Therefore, the luminescent colors in Examples 1, 2, 4, and 5 can be evaluated as being particularly preferable for illumination applications.

It is a schematic sectional drawing which shows an example of embodiment of this invention.

Explanation of symbols

A organic electroluminescence element 1 anode 2 cathode 3 light emitting layer 3a blue region light emitting layer 3b yellow region light emitting layer 3c red region light emitting layer

Claims (8)

An organic electroluminescence element in which a plurality of light emitting layers are laminated between an anode and a cathode, wherein the plurality of light emitting layers are:
A blue region light emitting layer having a maximum light emission wavelength in a wavelength region of 450 to 470 nm;
A yellow region light emitting layer having a maximum emission wavelength in a wavelength region of 550 to 570 nm;
A red region light emitting layer having a maximum light emission wavelength in a wavelength region of 600 to 620 nm;
Including
Among the blue region light emitting layer, yellow region light emitting layer and red region light emitting layer, the red region light emitting layer has the highest light emission intensity, the blue region light emitting layer has the lowest light emission intensity,
In addition, the entire emission color is classified into a light bulb color or warm white as defined in JIS Z9112,
And the organic electroluminescent element characterized by the average color rendering index of the whole luminescent color being 80 or more. An organic electroluminescence element in which a plurality of light emitting layers are laminated between an anode and a cathode, wherein the plurality of light emitting layers are:
A blue region light emitting layer having a maximum light emission wavelength in a wavelength region of 450 to 470 nm;
A yellow region light emitting layer having a maximum emission wavelength in a wavelength region of 550 to 570 nm;
A red region light emitting layer having a maximum light emission wavelength in a wavelength region of 600 to 620 nm;
Including
Among the blue region light emitting layer, yellow region light emitting layer and red region light emitting layer, the blue region light emitting layer has the highest light emission intensity, the red region light emitting layer has the lowest light emission intensity,
In addition, the entire emission color is divided into daylight white color or daylight color as defined in JIS Z9112.
And the organic electroluminescent element characterized by the average color rendering index of the whole luminescent color being 80 or more. An organic electroluminescence element in which a plurality of light emitting layers are laminated between an anode and a cathode, comprising an intermediate layer interposed between two light emitting layers of the plurality of light emitting layers,
The intermediate layer is formed from a layer forming an equipotential surface or a charge generation layer;
The plurality of light emitting layers are
A blue region light emitting layer having a maximum light emission wavelength in a wavelength region of 450 to 470 nm;
A yellow region light emitting layer having a maximum emission wavelength in a wavelength region of 550 to 570 nm;
A red region light emitting layer having a maximum light emission wavelength in a wavelength region of 600 to 620 nm;
Including
An organic electroluminescence device having an average color rendering index of 80 or more of the entire luminescent color. Among the blue region light emitting layer, yellow region light emitting layer and red region light emitting layer, the red region light emitting layer has the highest light emission intensity, the blue region light emitting layer has the lowest light emission intensity,
4. The organic electroluminescence device according to claim 3 , wherein the entire emission color is classified into a light bulb color or warm white color defined in JIS Z9112. Among the blue region light emitting layer, yellow region light emitting layer and red region light emitting layer, the blue region light emitting layer has the highest light emission intensity, the red region light emitting layer has the lowest light emission intensity,
4. The organic electroluminescence device according to claim 3 , wherein the entire emission color is divided into a daylight white color or a daylight color defined in JIS Z9112. An organic electroluminescence element in which a plurality of light emitting layers are laminated between an anode and a cathode, wherein the plurality of light emitting layers are:
A blue region light emitting layer having a maximum light emission wavelength in a wavelength region of 450 to 470 nm;
A yellow region light emitting layer having a maximum emission wavelength in a wavelength region of 550 to 570 nm;
A red region light emitting layer having a maximum light emission wavelength in a wavelength region of 600 to 620 nm;
Including
Among the blue region light emitting layer, yellow region light emitting layer and red region light emitting layer, the red region light emitting layer has the highest light emission intensity, the blue region light emitting layer has the lowest light emission intensity,
The organic electroluminescence device is characterized in that the entire emission color is classified into a light bulb color or warm white as defined in JIS Z9112. An organic electroluminescence element in which a plurality of light emitting layers are laminated between an anode and a cathode, wherein the plurality of light emitting layers are:
A blue region light emitting layer having a maximum light emission wavelength in a wavelength region of 450 to 470 nm;
A yellow region light emitting layer having a maximum emission wavelength in a wavelength region of 550 to 570 nm;
A red region light emitting layer having a maximum light emission wavelength in a wavelength region of 600 to 620 nm;
Including
Among the blue region light emitting layer, yellow region light emitting layer and red region light emitting layer, the blue region light emitting layer has the highest light emission intensity, the red region light emitting layer has the lowest light emission intensity,
In addition, the organic electroluminescence device is characterized in that the entire emission color is classified into a daylight white color or a daylight color defined in JIS Z9112. An illuminating device comprising the organic electroluminescence element according to any one of claims 1 to 7 .

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