JP3528470B2 - Micro-optical resonator type organic electroluminescent device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a micro optical resonator structure.
Utilizes a narrow half-width emission spectrum and sharp forward
This is related to a monochromatic light emitting device having light emission directivity.
Used for elements and communication light emitting devices. [0002] 2. Description of the Related Art In recent years, diversification of information equipment and space saving have been achieved.
And consume less space than CRTs.
There is a growing need for a flat display device. Like this
Liquid crystal, plasma display, etc.
However, in recent years, the display is sharp,
Expectations for organic electroluminescent devices that can be driven by a
ing. [0003] At present, organic electroluminescent devices
The performance is 1000 cd / m at a driving voltage of 10 V or less.
It has a luminance of 2 or more and emits three primary colors of blue, green and red.
Noh. However, the emission spectrum of the luminescent material
Wide color, poor color purity and wide angle from device
There is a problem that light is radiated over the light and the directivity is low. Recently, metal mirrors or multilayer mirrors have been used.
When a micro optical resonator is formed in the device using
The light corresponding to the cavity spacing is emphasized and emitted from the device.
Is reported to be. Specifically,
Research on monochromatic emission and high directivity has been promoted (Ap
pl.Phys.Lett., 63,594 (1993), (Appl.Phys.Lett., 63,203
2 (1993).). FIG. 16 shows a micro optical resonator having the above-mentioned structure.
When the observation angle with respect to the element is 0, 30, or 60 degrees,
Combined emission spectra a, b, c and no micro-optical resonator
The emission spectrum d in this case is shown. Where the observation angle
The degree is the observer's view of the normal to the light emitting surface of the device.
Angle. [0006] As shown in FIG.
Compared to the emission spectrum d without
Emission spectrums a, b, and c at the time of attachment
Emission of a spectrum having a small particle size is obtained. [0007] However, a micro-optical resonator
The emission spectra a, b and c with
The peak position changes depending on the angle of the change. I mean
As the viewing angle increases, the emission color changes to shorter wavelengths,
Light of various wavelengths is visible. FIG. 17 shows a case where a micro optical resonator is attached.
Of the light intensity seen from that direction relative to the viewing angle
Cloth is shown. In FIG. 17, wavelength 1, wavelength 2, wavelength
3 correspond to the emission spectra a, b, and c in FIG. 16, respectively.
The intensity of the light,
The intensity distribution of non-lighting light is represented by all wavelengths in the figure.
As can be seen from FIG.
Directivity is recognized for each, but the finger
There is a problem that there is almost no tropism. That is, wide
The light intensity distribution spreads over the observation angle. FIG. 16 shows a target emission peak a,
Another emission peak on the long wavelength side in addition to b and c (low order mode)
Are observed, and the mode is a multiple mode. Because of this,
There was also a problem that the degree was reduced. [0010] The cause of the multimode is a minute optical resonator.
It is thought that the thickness of the organic compound and the transparent conductive layer in the
It is. Generally, a transparent material such as indium tin oxide (ITO) is used.
Example when the total of the bright conductive layer and the organic compound layer is 300 nm or more
Has been reported, but lower-order modes have been removed from multiple modes.
In order to achieve a single mode, an organic compound and transparent conductive
It is necessary to further reduce the thickness of the layer. Regarding the angle dependence of the emission spectrum,
Utilizing a compound with a sharp peak emission spectrum
An emission spectrometer with small angle dependence and narrow half width
It has been reported that octols are strongly emitted to the front of the element.
(Appl. Phys. Lett., 65, 15 (1994)). But this material
The fluorescence intensity of the material is not high,
Good light emission has not been obtained. The present invention has been made in view of the above-mentioned conventional problems.
The purpose is to achieve high luminous efficiency but high luminous efficiency.
Organic light-emitting materials with a wide spectrum can be used,
The half-width of the beam is narrow and directivity forward without spectral
And a micro-optical resonator type organic electroluminescent device with excellent monochromaticity
To provide. [0013] [MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
According to the present invention, two types of layers having different refractive indexes are alternately laminated.
Multilayer mirror and a multilayer mirror formed on the multilayer mirror
Transparent conductive layer as anode, formed on the transparent conductive layer
One or more organic compound layers;
Metal mirror as a cathode formed on top and capable of reflecting light
And a micro-optical resonator type organic electroluminescent device having
The organic compound layer by the multilayer mirror and the metal mirror.
A micro-optical resonator for the light output from the
ShakerSet the optical length of 1.5 times the resonance target wavelength,
Maximum emission wavelength λm of light output from the organic compound layer [ n
m ] , The maximum emission wavelength of the emission is (λm-1
0) [ nm ] From (λm-50) [ nm ] Rangething
It is characterized by. According to the above configuration, the multilayer mirror and the metal mirror
Organic compound by a micro optical resonator composed of
Of the light output from the object layer, a specific wavelength
Can be Therefore, in the light emitted from the organic compound layer,
Light of a desired wavelength can be extracted from the light source. According to another embodiment of the present invention,
In the micro-optical resonator type organic electroluminescent device of the present invention,
The optical length L of the small optical resonator is determined by the immersion of light into the multilayer mirror.
Formulas that take into account (Equation 1) Here, neff is the effective refractive index of the multilayer mirror, and Δn is
The difference between the refractive indices of the two layers of the multilayer mirror, ni and di
The refractive index and layer thickness of the organic compound layer and the transparent conductive layer, and θ are organic compounds.
At each interface between the material layers or between the organic compound layer and the transparent conductive layer.
Given by the angle between the incoming light and the normal to the interface
And the optical length L is 1.5 times the target emission wavelength.
And features. In the above configuration, λ / 2 in the first term of the equation
(Neff / Δn) indicates that the resonating light is a multilayer mirror.
It represents the depth of penetration. As you can see from the first paragraph
And neff and Δn are the materials constituting the multilayer mirror.
Since the light wavelength λ is determined,
The penetration depth will also be determined. Also, in the second paragraph
The refractive index ni of each layer is also a constant determined by the material,
The thickness of each layer of the multilayer mirror is set to λ / 4.
You. Therefore, the optical length L is determined by the transparent conductive layer and the organic compound layer.
Can be controlled by changing the thickness di
You. The wavelength of the light resonating with the micro optical resonator is as described above.
Is determined by the optical length L of That is, the optical length L is
Light equivalent to an integral multiple of 1/2 wavelength resonates in a micro optical resonator
it can. Therefore, the total thickness of the transparent conductive layer and the organic compound layer
When the optical length L is reduced by reducing the thickness,
The wavelength of light emitted from the element by resonance with the device is also on the short wavelength side
Change. In this case, 1.5 times the half wavelength is optical
Light having the same length L has the longest wavelength as resonating light.
Therefore, the light emitted from the device has a shorter wavelength.
You. When the light emitted from the device has a short wavelength,
It is possible to obtain light with high directivity to light. Also, the optical length
When L is reduced, the light emission mode of the element is set to a single mode
be able to. According to still another embodiment of the present application,
In the micro-optical resonator type organic electroluminescent device of the present invention,
The uppermost layer of the multilayer mirror is composed of a transparent conductive layer,
Of the multilayer mirror and the transparent conductive layer
It is characterized by that. According to the above construction, the uppermost layer is a multilayer mirror.
And the transparent conductive layer, so the element thickness
Thus, the transparent conductive layer can be made thicker. According to still another embodiment of the present application,
In the micro-optical resonator type organic electroluminescent device of the present invention,
And the desired emission wavelength is the emission spectrum of the luminescent material used.
Rise portion on the shorter wavelength side than the peak wavelength λm
Is set. According to still another embodiment of the present application,
In the micro-optical resonator type organic electroluminescent device of the present invention,
The organic compound layer has a single-layer structure of only the light-emitting layer,
Layer and light-emitting layer or two-layer structure of light-emitting layer and electron transport layer, holes
Any one of the three-layer structure of the transport layer, the light emitting layer, and the electron transport layer
It is characterized by consisting of According to still another embodiment of the present application,
In the micro-optical resonator type organic electroluminescent device of the present invention,
The optical length of each layer of the multilayer mirror is equal to the target emission wavelength.
/ 4. According to each of the above structures, the light of the micro optical resonator
By controlling the President and optimizing the desired emission wavelength
Micro-optical resonator type with high monochromaticity and high directivity
An electroluminescent device can be obtained. [0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.
Will be described with reference to the drawings. FIGS. 1 to 4 show a minute optical resonance according to the present invention.
1 shows a cross-sectional view of an embodiment of the organic electroluminescent device.
In these embodiments, the transparent substrate 10 has a multilayer
A film mirror 12 is formed. The multilayer mirror 12
Two types of oxides, nitrides or semiconductors with different refractive indexes
Are alternately laminated. The cost of that combination
Examples of tables include TiO2 and SiO2, SiNx and SiO2.
2, dielectrics such as Ta2 O5 and SiO2, and GaAs and G
There is a semiconductor multilayer film such as aInAs. The multilayer mirror 12 reflects light at the interface between the layers.
Light, but the light reflected from each interface reinforces each other
The wavelength of the light to be used (the desired emission wavelength) λ
On the other hand, the thickness is set to λ / 4. The transparent conductive layer 14 is provided on the multilayer mirror 12.
Is formed. This transparent conductive layer 14 functions as an anode.
Works, but it uses materials with a high work function,
Holes as carriers are easily injected into the organic compound layer
ing. As the transparent conductive layer 14, for example, Pt, A
metals such as u, Ni, Cu, Ag, Ru, Cr and ITO
(Indium Tin Oxide), SnO2, I
a transparent conductive oxide such as n2O3, ZnO, or the like;
These composites can be mentioned. On the transparent conductive layer 14, at least one layer
An organic compound layer is formed. As an organic compound layer
Is the hole and electron carriers injected from the anode and cathode
To the light emitting layer 16 that emits light by recombination of
Hole transport layer 18 for transporting holes and electron transport for transporting electrons
There are three types of transport layers 20. These can be illuminated as needed
Single layer structure using only layer 16, light emitting layer 16 and hole transport
Use layer 18 or light emitting layer 16 and electron transport layer 20
Two-layer structure, light-emitting layer 16, hole transport layer 18, and electron transport layer 2
It is used as a three-layer structure using 0. The emission wavelength emitted from the light emitting layer 16 is
By changing the light emitting material used for the light layer 16,
You can choose. As the light emitting layer 16 described above, 8-hydro
Xyquinoline metal complex (JP-A-59-194393)
Metal chelated oxinoid compounds such as
Ene derivatives, perinone derivatives, bisstyrylbenzene induction
Conductors (JP-A-3-116186)
be able to. For polymer-based materials, poly (paraphenylene)
Lenvinylene) -based derivatives are typical examples. Luminous switch
As for the shape of the spectrum, the rise on the short wavelength side is sharp.
It is desirable. The material of the hole transport layer 18 is preferably
A compound having an aromatic tertiary amine is typical. This example
Are arylamines and triarylamines
There are compounds (USP No. 4175960, USP No. 453950). Special
In addition, a tertiary amine compound having high heat resistance is desirable.
There are multimers of triarylamines. The electron transporting layer 20 is typically 8
-Hydroxyquinoline metal complex (JP-A-59-1943)
93) and oxazole derivatives (Appl. Phys. Lett. 55, 1489)
(1989)). The light emitting layer 16, the hole transport layer 18, the electron
The material of the transport layer 20 is used for an organic light emitting device.
All conventionally known materials can be used.
You. In addition, the organic compound layer is composed of only the aforementioned organic compound alone.
Not improved, poly-
Laphenylene vinylene) derivative, dispersed in general-purpose polymer
A mixed layer that has been applied is also available. Of these organic compounds
The type and the configuration of the laminated structure are not particularly limited. A metal mirror is provided on these organic compound layers.
22 are formed. The metal mirror 22 serves as a cathode
Functions to reflect light emitted from the light emitting layer 16
It also has functions. The metal mirror 22 has a work function
Electrons as carriers are used in organic compound layers
It is easy to be injected into. In addition, high reflectivity of light
Is desirable, and specifically has a reflectance of 90% or more.
It is desirable. A specific example of the metal mirror 22 is A
1, Mg, Ca, Li, Na, Ag, Y and alloys thereof
There is. The thus obtained micro optical resonator type
The electroluminescent element improves the stability, especially moisture and acid in the atmosphere.
For protection against element, separate protective layer
The whole may be put in a cell. Also emitted from the element
Method of covering with heat conductive protective layer to release generated heat
Or a similar metal or other metal on the metal mirror
It is possible to cover with. With these, the stability of the element
improves. The micro optical resonator type organic according to the present invention described above
In an electroluminescent device, a multilayer mirror 12 and a metal mirror are used.
A minute optical resonator is formed by the pair of -22. This minute
Identification of light emitted from the light emitting layer 16 by the optical resonator
Those with wavelengths resonate and are strengthened. Therefore, the light emitting layer 16
The light of the desired wavelength from the light emitted from the
Has high luminous efficiency, but the emission spectrum
Even when an organic light emitting material having a wide
Light emission of a sharp peak with a narrow value width can be obtained. FIG. 5 shows a micro-optical resonator type organic electroluminescent device according to the present invention.
Cross section of micro-optical resonator in field emission device is shown.
It is. FIG. 5 shows that the organic compound layer has only the light emitting layer 16.
Although an example of a layer structure is shown, a two-layer structure and a three-layer structure
In this case, the principle described below is the same. As shown in FIG. 5, the micro optical resonator is
It is composed of a multilayer mirror 12 and a metal mirror 22.
The transparent conductive layer 14 and the light emitting layer 16 (organic compound
Layer). Therefore, in a micro optical resonator,
The thickness of the light emitting layer 16, the thickness of the transparent conductive layer 14, and the respective
When the light is resonating with the product of the index of refraction, the multilayer mirror 1
The optical length is the sum of the depth of penetration into 2 and the optical length. The optical length L of the micro optical resonator is given by the following equation.
Is calculated. [0040] (Equation 2) Here, λ is the wavelength of the resonating light, and neff is the multilayer film.
The effective refractive index of the mirror, Δn, is the difference between the two layers of the multilayer mirror.
The difference in refractive index, ni and di are transparent conductive layers in the micro optical resonator
And the refractive index and thickness of the organic compound layer, and θ are the same as those of the organic compound layer.
Incident on each interface between the organic or organic compound layer and the transparent conductive layer.
This is the angle between the light that is emitted and the normal that stands on the interface. In the above equation, the first term λ / 2 (neff
/ Δn) means that the resonating light permeates the multilayer mirror 12
It represents the depth to fit. As can be seen from the first term, ne
ff and Δn depend on the material constituting the multilayer mirror 12.
Since it is a constant, it is soaked when the wavelength λ of light is determined.
It will also determine the depth of insertion. In addition, each
The refractive index ni of the layer is also a constant determined by the material, and
The thickness of each layer of the multilayer mirror 12 is set to λ / 4 as described above.
Is defined. Accordingly, the optical length L is equal to the length of the transparent conductive layer 14.
And control by changing the thickness di of the light emitting layer 16.
be able to. The wavelength of the light resonating with the micro optical resonator is as described above.
Is determined by the optical length L of That is, the optical length L is
Light equivalent to an integral multiple of 1/2 wavelength resonates in a micro optical resonator
it can. FIG. 5 shows three times the half wavelength, that is, 1.5 waves.
Light whose length is equal to the optical length L is drawn, but light that resonates
Is the longest wavelength. As described above, the transparent conductive layer 14 and the organic
The total thickness of the compound layer was reduced and the optical length L was reduced.
Of the light emitted from the element resonating with the micro optical resonator
The wavelength also changes to the shorter wavelength side.Use higher order mode
IWhen the light emitted from the device has a short wavelength,Low order mode
Than long-wavelength light emission usingDirectivity in front of the element
High light can be obtained. Further, the optical length L is reduced.
Then, the light emission mode of the device can be set to a single mode.
You. That is, the optical length L of the micro optical resonator is controlled.
Then, the wavelength of light emitted from the device is shown in FIG.
As in the case where there is no micro-optical resonator,
The wavelength λm of the peak of the emission spectrum of the optical material itself
Shorter wavelength and the rise of emission spectrum
The wavelength (nm) range of A, which is a part. A wavelength (n
m) The range is, for example, from (λm-10) to (λm-
The range of 50) is good. On the shorter wavelength side than (λm-50)
Since the emission intensity of the light emitted from the light emitting layer 16 is reduced,
It cannot function as a light emitting element. Also, (λm-1
0) On the longer wavelength side, the observation angle changes, and
When the emitted light changes to the short wavelength side, a minute optical resonance
Emission spectrum without the instrument corresponds to that wavelength
Since light exists at high intensity, when observed from that angle
These lights are visible, and the light emitted from the device
Dependence on the viewing angle appears. Therefore, from the element
The emitted light has strong directivity in front of the element unless it is split.
Can not get. On the other hand, within the range of A described above,
The angle of view changes and the light emitted from the element shifts to the shorter wavelength side
Even if it changes, the emission spectrum without a micro optical resonator
Does not have light corresponding to that wavelength or has an intensity
Because it is extremely low, the light output from the element
Dependency can be eliminated, and directivity to the front of the device is high.
You can get bright light. The optical length L shown in FIG.
When set to, the target light emitted from the element is
It is not light that resonates at three times a half wavelength with respect to the optical length L.
The light resonates four times or more. This place
In this case, there is also light that resonates at three times the half wavelength, and this light is
Remains in the high intensity region in the above emission spectrum
As a result, a low-order mode is set (see FIG. 12).
The emitted light is in multiple mode. As described above, in order to obtain a single mode light,
President L is 1.5 times the wavelength of the target light (1/2 wavelength
3 times). One way to do this
The transparent conductive layer 14 in the second term of the above formula (1)
And the thickness di of the organic compound layer may be reduced. This place
In order to make the optical length L 1.5 times the emission wavelength,
The total thickness of the conductive layer 14 and the organic compound layer is at least 150
nm or less. Alternatively,
The multilayer mirror 12 in which the upper layer is replaced by the transparent conductive layer 14 is
There are ways to use it. In this method, as shown in FIG.
As described above, a low refractive index compound and a high refractive index
Index compound is alternately laminated, and the last low refractive index compound
A transparent conductive compound is formed thereon. In FIG.
The uppermost layer of the multilayer mirror 12 is transparent to the multilayer mirror 12.
The light guide layer 14 is also used. Such a multilayer film
Of a micro-optical resonator type organic electroluminescent device using
An example is shown in FIG. In FIG. 13, a multilayer mirror is shown.
12 itself acts as a transparent conductive layer 14
Therefore, it is not necessary to provide the transparent conductive layer 14 independently. Follow
Therefore, there is a margin for the thickness of the micro optical resonator.
The thickness of the transparent conductive layer 14 can be increased accordingly.
You. Thereby, the electric resistance of the transparent conductive layer 14 is reduced.
I can do it. FIG. 6 shows the light transmission of the multilayer mirror 12.
Rates are also shown. In the light transmittance shown in FIG.
The emission region, that is, the width of the stop band
So that it can cover the emission spectrum in the absence of
Is set to The reflectivity in that region is 50 to 99.9
% (In terms of transmittance, 50 to 0.1%) is preferable.
Can be appropriately selected according to the use of the element. one
In general, the higher the reflectance, the half value of the light spectrum obtained
The width becomes narrow and becomes a sharp peak. Hereinafter, a micro-optical resonator type organic electroluminescent device according to the present invention will be described.
A practical example of a field emission device and a comparative example are explained.
I will tell. Embodiment 1 The wavelength of light emitted from the device
With a small optical resonator type under the following conditions,
The electroluminescent device was manufactured. RF magnetron spa on a transparent glass substrate
SiO2 and TiO2 in the order of TiO2 layer
To form a multilayer mirror consisting of four layers alternately stacked
did. The center wavelength of the stop band at that time is 550 nm
Designed with. The transparency of this multilayer mirror in the stop band
The excess rate was 10%. An RF mask is placed on this multilayer mirror.
60n transparent conductive layer (ITO) by guntron sputtering
m was formed. After thoroughly cleaning these substrates with an organic solvent,
It was fixed in an empty vapor deposition device. First, as a hole transport layer,
20 nm of a phenyldiamine derivative,
Lumiquinolinol complex was deposited to a thickness of 30 nm. This
The total of the transparent conductive layer and the organic compound layer is 110 nm.
Was. The triphenyldiamine derivative and a
1 shows a structural formula of a lumiquinolinol complex. [0053] Embedded image Embedded imageThe optical length of the micro optical resonator in this device is
And organic compound layer thickness and refractive index and immersion in multilayer mirror
From the amount of penetration, the target wavelength is calculated by the above-described equation (1).
1.5 times of 500 nm, that is, 750 nm. Most
Later, a MgAg alloy (10: 1) is used as a cathode to a thickness of 180 nm.
Evaporated. As described above, the minute optical resonator corresponding to FIG.
Type organic electroluminescent device was produced. An 8V voltage is applied to this element.
When pressure was applied, clear blue-green light emission was obtained. So
FIG. 7 shows the emission spectrum of. The emission spectrum is 51
There is a peak only at 0 nm, no other peak is observed,
It can be seen that the light emission is one mode. Also, the observation angle θ
Even if it changes, the shift of the emission peak is small and the intensity is also sharp
It is getting smaller. Thus, the light emitted from the device
It can be seen that the observation angle dependency has been removed. Total emission light emission measured without spectroscopy
The pattern is shown in FIG. Despite not spectroscopy
However, strong directivity was obtained in front of the element (angle = 0 °).
Stronger light than an element without a micro optical resonator in front of the element
It was also found to have been released. Comparative Example 1 RF Magnestron sputtering method
Then, TiO2 and SiO2 will be SiO2 layer at the end.
Thus, a multilayer mirror in which four layers were alternately laminated was formed.
The last step was to use the SiO2 layer because
Because a child had been proposed. On top of that, I was formed by RF magnetron sputtering.
TO was formed to a thickness of about 200 nm. On this substrate,
Aluminum quinolinol complex with 50nm of nildiamine derivative
The body was evaporated to 60 nm. As a result, the transparent conductive layer and the organic
The total thickness of the compound layer was 310 nm. In this comparative example, the top of the multilayer mirror was
Since the part is SiO2 with low refractive index,
Since there is not much reflection and when applying equation (1), this layer
Is added to the thickness of the transparent conductive layer, hole transport layer, and light emitting layer.
Need to be Therefore, the uppermost SiO2, transparent conductive
Layer, hole transport layer, light emitting layer thickness and refractive index and multilayer mirror
The optical length of the micro-optical resonator depends on the amount of
Is about 2.5 times the wavelength of 500 nm. Finally shade
As a pole, a 180 nm portion of MgAg alloy (10: 1)
Thickness and refraction of iO2, transparent conductive layer, hole transport layer, and light emitting layer
Rate and multilayer mirror deposition. FIG. 9 shows the emission spectrum of this comparative example.
Light emission having a sharp peak at 500 nm can be confirmed. Ma
Another emission peak was also observed on the long wavelength side,
It became a mode. In this long-wavelength side emission spectrum
Changes the observation angle θ, the emission peak increases toward the short wavelength side.
Moved. Comparative Example 2 Multilayer mirror as in the first embodiment
A 60 nm thick ITO is formed on the substrate on which
Was. On top of this, a 40 nm triphenyldiamine derivative was added.
An aluminum quinolinol complex of 50 nm was sequentially formed. Optics
The length was about 1.5 times the target wavelength of 570 nm.
Finally, a 180 nm vacuum deposition of a MgAg electrode was performed. The emission spectrum of the device of this comparative example is shown in FIG.
Shown in A sharp emission peak is observed at 570 nm. So
No other emission peaks were observed, and single-mode emission was observed.
You can see that it is. However, in this comparative example,
The target wavelength 570 nm is smaller than the range A shown in FIG.
Is also long wavelength, so if the observation angle θ is changed, the emission peak
The laser moved largely to the short wavelength side. In the specific light that was split
Although strong directivity was observed, the radiation pattern of total radiation was
Almost no directivity was observed as shown in FIG.
Was. Embodiment 2 FIG. Example of changing the material of the light emitting layer
Micro-optical resonator-type organic electric field that emits light of a color different from 1
Light emitting device was produced. An RF magnetron spa on a transparent glass substrate
SiO2 and TiO2 in the order of TiO2 layer
To form a multilayer mirror consisting of four layers alternately stacked
did. The center wavelength of the stop band is designed to be 620 nm.
Was. The transmittance of this multilayer mirror in the stop band is 1
It was 0%. RF magnetrons on multilayer mirror
60 nm of ITO was formed by a putter method. These boards are
After being sufficiently washed with a solvent, it was fixed in a vacuum evaporation apparatus. Next, as a hole transport layer, triphenyldiphenyl
Amine derivative 50 nm, phthaloperinone as light emitting layer
The derivative was deposited to a thickness of 50 nm. Finally, the metal electrode Mg
An Ag alloy was deposited by 180 nm. The structural formula of the phthaloperinone derivative is shown below.
Show. [0066] Embedded image When a voltage of 10 V was applied to the device of this example,
A bright yellow-green emission was obtained. From the emission spectrum, 54
There is a peak only at 0 nm, and no other peak is observed
Was. The radiation pattern can achieve strong directivity in front of the element.
Was. Embodiment 3 FIG. The emission color is different from that of Example 2.
A micro optical resonator type organic electroluminescent device was fabricated. An RF magnetron spa on a transparent glass substrate
SiO2 and TiO2 in the order of TiO2 layer
To form a multilayer mirror consisting of four layers alternately stacked
did. The center wavelength of the stop band of this multilayer mirror is
Designed at 700 nm. Stop bar of this multilayer mirror
The transmittance in the sand was 10%. On the multilayer mirror
Forming ITO 60nm by RF magnetron sputtering method
Was. Next, triphenyldiphenyl is used as a hole transport layer.
Amine derivative at 60 nm, perylene derivative as light emitting layer
Was deposited to a thickness of 60 nm. Finally, the metal electrode MgAg
180 nm of gold was deposited. The structural formula of the perylene derivative is shown below. [0071] Embedded image When a voltage of 10 V was applied to the device of this example,
A bright orange luminescence was obtained. From the emission spectrum
There is a peak only at 600 nm, and no other peak is observed.
won. Radiation pattern achieves strong directivity in front of the element
did it. Embodiment 4 FIG. RF magnetro on glass substrate
The low-refractive index compound, SiO2, was
6.5 nm, TiO2 which is a high refractive index compound
nm, in this order, alternately three times each, then SiO2,
Later, ITO as a transparent conductive compound was 73.7 nm
To form a multilayer mirror as shown in FIG.
Was. This multilayer mirror can be used only for SiO2 and TiO2.
Performance comparable to that of the combination, with a reflectance of over 90%
Was completed. On top of this multilayer mirror, triphenylamide
A 50-nm tetramer is formed, and then an aluminum quinolinol complex is formed.
1% quinacridone by co-evaporation of body and quinacridone
A 60 nm doped light emitting layer was formed. Then, Mg
An Ag electrode (metal mirror) was formed to a thickness of 180 nm. The following describes the triphenylamine tetramer and key
1 shows the structural formula of nacridone. [0074] Embedded image Embedded image When a voltage of 6 V was applied to the device of this example, the device was sharp.
Green light was obtained, and the emission peak was as shown in FIG.
530 nm as shown. In FIG.
Indicates the wavelength on the horizontal axis and the emission intensity on the vertical axis.
I have. FIG. 15 shows the emission of light from the device of this example.
The radiation pattern is shown. As can be seen from FIG.
It was always possible to achieve forward directivity with high efficiency. in this case,
The light intensity on the front side is up to 5000 cd / m^Two Reached
Was. The light intensity can be increased because the transparent light
The thickness of the electrical layer can be increased and the electrical resistance can be reduced
As a result, the heat generated by the current can be kept low,
This is because many flows can flow. [0075] As described above, according to the present invention,
Excellent monochromaticity without using lenses and filters
Optical Oscillator Type Organic with High Efficiency and Forward Directivity
An electroluminescent device can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an example of a micro-optical resonator type organic electroluminescent device according to the present invention. FIG. 2 is a cross-sectional view of another example of a micro-optical resonator type organic electroluminescent device according to the present invention. FIG. 3 is a cross-sectional view of still another example of the micro-optical resonator type organic electroluminescent device according to the present invention. FIG. 4 is a cross-sectional view of still another example of the micro-optical resonator type organic electroluminescent device according to the present invention. FIG. 5 is a cross-sectional view of a micro-optical resonator in the micro-optical resonator type organic electroluminescent device according to the present invention. FIG. 6 is a diagram illustrating a relationship between an emission spectrum, a transmittance of a multilayer mirror, and an emission mode position in a case where a micro optical resonator is not provided. FIG. 7 is a diagram showing an emission spectrum of Example 1 and its angle dependence. FIG. 8 is a diagram illustrating a radiation pattern according to the first embodiment. FIG. 9 is a diagram showing an emission spectrum of Comparative Example 1 and its angle dependence. FIG. 10 is a diagram showing an emission spectrum of Comparative Example 2 and its angle dependence. FIG. 11 is a diagram showing a radiation pattern of Comparative Example 2. FIG. 12 is a cross-sectional view of another example of the micro-optical resonator in the micro-optical resonator type organic electroluminescent device according to the present invention. FIG. 13 is a cross-sectional view of still another example of the micro-optical resonator type organic electroluminescent device according to the present invention. FIG. 14 is a diagram showing an emission spectrum of Example 4. FIG. 15 is a diagram illustrating a radiation pattern according to the fourth embodiment. FIG. 16 is a diagram showing a general emission spectrum of a conventional organic electroluminescent device having a micro optical resonator and its angle dependence. FIG. 17 is a diagram showing a general radiation pattern of a conventional organic electroluminescent device having a micro optical resonator. [Description of Signs] 10 transparent substrate, 12 multilayer mirror, 14 transparent conductive layer, 16 light emitting layer, 18 hole transport layer, 20 electron transport layer, 22 metal mirror.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-142171 (JP, A) JP-A-6-275381 (JP, A) JP-A-9-283271 (JP, A) JP-A-7-142 282981 (JP, A) JP-A-9-92466 (JP, A) JP-A-8-8061 (JP, A) JP-A-3-163882 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05B 33/00-33/28

Claims (1)

(57) [Claim 1] A multilayer mirror in which two kinds of layers having different refractive indexes are alternately laminated, and a transparent conductive layer as an anode formed on the multilayer mirror. A multilayer mirror having: one or more organic compound layers formed on the transparent conductive layer; and a metal mirror formed on the organic compound layer as a cathode capable of reflecting light. And the metal mirror constitute a micro optical resonator of light output from the organic compound layer,
The optical length of the micro optical resonator is set to 1.5 times the resonance target wavelength.
And the maximum emission wavelength λm of the light output from the organic compound layer.
[ nm ] , the maximum emission wavelength of the emission is (λm-1
0) A micro-optical resonator type organic electroluminescent device characterized by being in the range of [ nm ] to (λm-50) [ nm ] .