JP2002184566A - Electroluminescent element and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroluminescent element which prevents adverse effect of outside light and aims at prevention of obscurity in visibility. SOLUTION: The electroluminescent element, with at least one face of an electroluminescent layer 4 as a display surface, is provided with a different phase film 2 between the electroluminescent layer 4 and a deflection film 1 in the direction of the normal line of the display surface D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescence device (hereinafter referred to as "EL device") and a method for producing the same, and more particularly, to a base material in which a retardation film and a deflection film are specified in a specific arrangement order. EL element using a flexible substrate having retardation characteristics and a method for manufacturing the same.

[0002]

2. Description of the Related Art Since an EL device is a device having a self-luminous property, a so-called LC combining a liquid crystal and a backlight is used.
Compared with the D module, it has advantages such as thinness, wide viewing angle, and fast response speed. Especially various organic E in recent years
The L element has been proposed and its practical use is rapidly advancing. In particular, practical application to a display panel is remarkable, and a display panel is configured by two-dimensionally arranging a plurality of organic EL elements on the same plane (for example, an XY matrix type), and display in which these elements are independently driven is performed. Panels are on the market. In the future, it is expected to be installed in mobile terminal devices such as mobile phones.

[0003] A display panel to be mounted on a portable terminal device is required to be thin, light, and low in cost. Also, a panel having a curved surface as a design element has been required. However, since the conventional display panel uses glass as a base material, it is difficult to obtain a curved surface and it is difficult to meet the above demand.

When providing a panel having a curved surface, it is desirable to use a highly flexible substrate such as a polymer film instead of a glass substrate. For example, JP-A-2-251
No. 429, JP-A-2-253593 and JP-A-7-078690, a polymer film is used as a base material, and a light-transmissive electrode is formed on the polymer film. Electrode and the other
There has been proposed a flexible organic EL element obtained by providing a single layer or a plurality of layers including a light emitting layer made of an organic compound between two electrodes.

The basic structure of an organic EL device is, for example, a structure in which an anode, a light-emitting layer, and a cathode are sequentially laminated on the base material, or a structure in which a cathode, a light-emitting layer, and an anode are sequentially laminated on the base material. . In some cases, a hole layer is provided between the anode and the light emitting layer, or an electron injection layer is provided between the cathode and the light emitting layer. The hole layer and the electron injection layer are also called a carrier transport layer. That is, it is a layer provided to facilitate movement of electrons or holes between the electrode and the light emitting layer. When the organic EL element having such a configuration is used as a display element, an observer observes light emitted between the electrodes and transmitted through the transparent base material. Further, of a pair of electrodes (anode and cathode) constituting such an organic EL element, an electrode located on a light extraction surface (light emitting surface) side as a light emitting element, that is, disposed between a substrate and a light emitting layer. The electrode is transparent. On the other hand, an electrode located on the side opposite to the light extraction surface side (hereinafter, referred to as
The counter electrode is made of a reflective film such as a metal thin film.

[0006]

Among the above-mentioned electrodes facing each other, the reflective film such as a metal thin film has a high reflectance of visible light, for example, outdoors under sunlight or indoors under fluorescent lamps. When the organic EL element emits light, external light such as sunlight or light from a fluorescent lamp passes through the transparent substrate and the light emitting layer, is reflected by the reflective film, and goes out of the organic EL element through the light emitting layer and the transparent substrate. Is emitted. That is, in addition to the self-emission light of the organic EL element, external light is also reflected by the reflection film and emitted out of the organic EL element. As a result, the display of the organic EL element becomes unclear for the observer. More specifically, low contrast is observed.

In particular, when the organic EL element has a curved surface,
External light reflected by the reflective film concentrates in a specific direction. As a result, the display of the organic EL element becomes unclear when observed from a specific direction.

The present invention has been made in view of the above problems, and has as its object to provide an EL element in which the influence of external light is prevented.

[0009]

The inventor of the present invention has found that such a problem caused by external light can be solved by providing a specific member between a light emitting layer and an observer observing an organic EL element. This problem is not limited to organic EL devices,
Focusing on the issue that also applies to the L element,
The present invention has been made.

That is, the EL device of the present invention is an EL device having at least one surface of an electroluminescence layer as a display surface, and comprises a retardation film and a deflection film, wherein the retardation film is It is provided between the electroluminescent layer and the deflection film in a direction normal to the display surface.

[0011] The EL device of the present invention has a further feature that "the transparent substrate is arranged so that the transparent substrate has
"Being provided between the electroluminescence layer and the retardation film", "The transparent substrate is a glass substrate", "The transparent substrate is a resin", "The retardation film" Is a λ / 4 film ”,“ the electroluminescent layer is a layer mainly composed of an organic compound ”, and“ the electroluminescent layer is a layer mainly composed of an inorganic compound ”. "A first electrode is provided on the side of the electroluminescence layer on which the retardation film is provided, and a second electrode is provided on a side opposite to the side on which the retardation film is provided, The electroluminescent layer is arranged between the first and second electrodes ", and the layer thickness of the first electrode in the normal direction is 5 "The film thickness in the normal direction of the first electrode should be a film thickness in the range of 500 ° to 5000 °," The electrode has a transmittance of light of 550 nm of at least 70% ”,“ the surface roughness of the first electrode is at least 20 ° and at most 500 ° ”,
“The surface roughness of the first electrode is 50 ° or more and 100 ° or less”, “the thickness of the second electrode in the normal direction is 500 ° or more and 5000 ° or less”, The layer thickness value in the normal direction of the electrode is 1000 ° or more and 3000 ° or less ”,“ the reflectance of the second electrode at 550 nm light is 80% or more ”,“ the linear expansion coefficient of the glass substrate ” Is 2 × 10
⁻⁶ / ° C. or more and 7 × 10 ⁻⁶ / ° C. or less ”,“ The glass substrate is at least one of alkali-free glass, quartz, borosilicate glass, and soda glass ”,“ The electroluminescence ” An alkali-free layer is provided on the surface of the glass substrate on which the layer is provided, and the electroluminescent layer is in contact with the alkali-free layer. "," The linear expansion coefficient of the retardation film is 50 × 10 ^{− 6} / ° C. or more and 100 × 10 ⁻⁶ / ° C. or less ”,“ the electroluminescent element is a display element of a display device ”, and“ the electroluminescent element is a display element of a plurality of first electrodes arranged in a stripe pattern ”. A second electrode including one electrode group and a plurality of the second electrodes arranged in a stripe shape;
An electrode group forms a matrix electrode group arranged so as to intersect in plan view, and a portion where the first electrode intersects with the second electrode in plan view is a display pixel portion of a display device. ",including.

Further, the EL device of the present invention is characterized in that at least a part of an electroluminescence layer is provided on at least a surface of a flexible substrate made of a retardation film.

The EL device of the present invention has a further feature that "the flexible substrate has the retardation film and the deflecting film, and the retardation film is in the normal direction of the surface. Being disposed between the deflection film and the electroluminescent layer "," the retardation film being a λ / 4 film ",
"The electroluminescent layer is a layer mainly containing an organic compound", "The electroluminescent layer is a layer mainly containing an inorganic compound", "The retardation film of the electroluminescent layer" A first electrode is provided on the side on which the phase difference film is provided, and a second electrode is provided on a side opposite to the side on which the retardation film is provided, and the electroluminescent layer is provided with the first second electrode. "The layer thickness value in the normal direction of the first electrode is a film thickness value in the range of 500 ° to 6500 °", and “the normal line of the first electrode”. The layer thickness in the direction should be in the range of 500 ° to 5000 ° ”.“ The first electrode has a transmittance of 550 nm light of 70% or more. "It" roughness of the surface of the first electrode is 20Å or more 500Å or less "," the first
The surface roughness of the electrode is 50 ° or more and 100 ° or less ”,“ The layer thickness value of the second electrode in the normal direction is 500 ° or more and 5000 ° or less ”,“ The method of the second electrode is The layer thickness in the line direction is 1000 °
Not less than 3000 ° ”and“ 5 of the second electrode ”.
The reflectance of 50 nm light is 80% or more "," The linear expansion coefficient of the retardation film is 50 × 10 ⁻⁶ / ° C. or more and 100 × 10 ⁻⁶ / ° C. or less ”; The luminescence element is a display element of a display device "," a first electrode group including a plurality of the first electrodes arranged in a stripe pattern, and a second electrode group including a plurality of the second electrodes arranged in a stripe pattern. " A two-electrode group forms a matrix electrode group arranged so as to intersect in plan view, and a portion where the first electrode intersects with the second electrode in plan view is a display pixel portion of a display device. That ".

Further, according to a method of manufacturing an EL device of the present invention, the method of manufacturing an electroluminescent device having a retardation film, a first electrode, an electroluminescent layer, and a second electrode is provided. Forming the first electrode, forming the electroluminescent layer on the surface of the retardation film, and forming the second electrode on the surface of the electroluminescent layer. It is characterized by.

The method for manufacturing an EL device according to the present invention further has the following features: "the retardation film is a resin";"the first electrode is an ITO electrode"; Performing the step of forming the first electrode by an RF magnetron sputtering method ”,“ the step of forming the first electrode is a step of forming the first electrode by a DC sputtering method ”, "The step of forming the first electrode is a step of forming the first electrode by an ion plating method".

According to the present invention, by providing the retardation film between the polarizing film and the electroluminescent layer, a part of the external light is filtered by the deflection film before a part of the external light enters the EL element. Is done. Light that has passed through the deflection film without being filtered is converted into circularly polarized light in a certain direction by the retardation film. Circular polarized light in a certain direction is reflected by a reflection film constituting an EL element and becomes circularly polarized light in a direction opposite to the certain direction. When the circularly polarized light of the opposite direction passes through the retardation film, it becomes light that cannot pass through the polarizing film. Therefore, even if external light enters the EL element and is reflected by the reflection film, it cannot exit the EL element.

The self-emitting light of the EL element passes through the retardation film, and only a part of the light is filtered by the polarizing film, and the remaining self-emitting light can be emitted to the outside of the EL element. Therefore, an EL element capable of preventing the influence of external light can be provided.

A flexible EL element can be provided by directly providing an electroluminescent layer on a flexible retardation film.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The feature of this embodiment is that a part of external light such as external light incident on an EL element is prevented from being lowered in contrast due to being reflected by an electrode having a high reflection ability and emitted from a light emitting surface. . Since a flexible base material is used, light can be emitted in a curved state, and the degree of freedom in product design increases. When no glass is used, the weight is low.

Hereinafter, embodiments of the present invention will be described.

(First Embodiment) The first embodiment of the present invention is characterized in that a retardation film is provided between a polarizing film and an electroluminescent layer.

FIG. 1 is a schematic sectional view showing the arrangement order of the components of the EL element according to the present embodiment.

1 is a polarizing film, 2 is a λ / 4 film which is a retardation film, 3 is a first electrode which is a transparent electrode, 4
Represents an electroluminescent layer as a light emitting layer, and 5
Denotes a second electrode which is a reflection film.

FIG. 1 is a schematic cross-sectional view. The electroluminescent layer 4 can be observed in a plane when the display surface D is viewed from the side where the observer observes. The normal direction of the display surface D is illustrated in FIG. 1, and the components denoted by reference numerals 1 to 5 are arranged in this normal direction in order.

The electroluminescence layer 4 emits light by a voltage applied between the first electrode 3 and the second electrode 5. The self-emitting light is emitted to the outside of the EL element in the order of the first electrode 3, the retardation film 2, and the polarizing film 1. An observer can observe the emitted self-emission light. This retardation film 2 is a flexible substrate.

The components denoted by reference numerals 1 to 5 shown in FIG. 1 are provided in contact with components adjacent to each other in the illustrated normal direction. Specifically, the electroluminescence layer 4 is provided on the display surface D in contact with the first electrode 3. The electroluminescence layer 4
Is provided in contact with the second electrode 5 on a surface facing the display surface D, that is, a surface opposite to the display surface D.

The first electrode 3 has a retardation film 2 on the side opposite to the side in contact with the electroluminescent layer 4.
Is in contact with

The electroluminescent layer 4 may be a so-called inorganic electroluminescent layer containing an inorganic compound as a main component, but in this embodiment, it is preferable to use a so-called organic electroluminescent layer containing an organic compound as a main component.

The electroluminescent layer 4 may be a single-layer thin film or a multilayer thin film.

As the first electrode (anode electrode) 3 having a light transmitting property, a material having a light transmitting property and a large work function (4 eV or more), such as a metal, an alloy or an oxide, is used as an inorganic material. Typically, CuI, ITO, SnO ₂ , Zn
O and the like. In addition, examples of the organic material include polyaniline.

The first electrode may be formed by various methods, and is formed by a physical method such as an RF magnetron sputtering method, a DC sputtering method, or an ion plating method. Furthermore, such a vapor deposition method can be used at a low temperature. For example, it is preferable that the retardation film, which is the object to be deposited, be made of a material such as resin that is easily deformed by heat because the first electrode does not need to be formed at a high temperature.

The second electrode (cathode electrode) is a metal or metal alloy having a small work function (4 eV or less), such as magnesium, an alloy of magnesium and silver, sodium, sodium and potassium. , An alloy of aluminum and lithium, indium and rare earth metals, and the like. These materials have excellent electron injecting properties as the second electrode. The work function of the anode may be selected to be relatively larger than the work function of the cathode, and the magnitude of the work function is not limited to 4 eV. Further, it is desirable that the sheet resistance value of both the first electrode and the second electrode is several hundred Ω / □ or less. In addition, the first electrode having light transmittance has a visible light wavelength (400 to 700).
(about nm) is better.

The thickness of the first electrode 3 is not less than 500.degree.
It is preferably within the range of 00 ° or less (1 ° = 10
^-10 m). The thicker the film, the lower the resistance. However, if the film is too thick, it is considered that cracks may occur in the electrodes due to the influence of mechanical stress or expansion and contraction due to heat. Therefore, the film thickness is preferably in this numerical range, and more preferably in the range of 500 ° to 5000 °.

The light transmittance of the first electrode is preferably 70% or more. The transmittance of the ITO film is measured according to JIS R
A value measured by placing the test piece perpendicularly to the measurement light at 1635 and transmitting the measurement light from the ITO side at an incident angle of 0 ° to the substrate side (substrate defined by JIS). For example, in the case of ITO, if it is 5000 ° or less, it can be said that the transmittance is 80% or more to obtain practically sufficient luminance.

The surface roughness of the first electrode is not less than 20 ° and not more than 50 °.
0 ° or less, preferably 50 ° or more and 10 ° or less.
More preferably, it is 0 ° or less. In addition, this surface is a surface on the side where the first electrode is in contact with the retardation film. If the surface is rough, it is difficult to contact the retardation film. The surface roughness is a surface roughness Rmax value at a length of 2.5 mm measured by a stylus type surface roughness meter.

The thickness of the second electrode is 500 ° or more and 50% or more.
It is preferably in the range of not more than 00 °, more preferably in the range of not less than 1000 ° and not more than 3000 °. The thicker the film, the lower the resistance. However, if the film is too thick, it is considered that cracks may occur in the electrodes due to the influence of mechanical stress or expansion and contraction due to heat. Therefore, it is preferable that the film thickness be within this numerical range.

The reflectance of the second electrode (the ratio of the intensity of the light wave reflected by the electrode surface to the intensity of the incident light wave) is 80 to 550 nm for the light of 550 nm in consideration of the efficiency of self-emission.
% Is preferable.

When the electroluminescent layer is an organic electroluminescent layer, the organic single-layer thin film which is the organic electroluminescent layer is a thin film substantially composed of one or more kinds of organic luminescent materials. Further, the organic single layer thin film may have a single layer structure in which a hole transport material or an electron injection material is included.

An organic multi-layer thin film may be used instead of the organic single-layer thin film. In this case, the organic multi-layer thin film is different from the light-emitting layer, that is, the layer structure of the organic light-emitting material can be visually distinguished from the layer structure.
It has a layer made of an organic light emitting material (that is, the electroluminescent layer 4) and a layer made of a hole transport material, or a layer made of an organic light emitting material and a layer made of an electron injection material.
For example, in the case of an organic single-layer thin film, the so-called concentration gradient structure in which the concentration of the hole transporting material or the electron injecting material in the organic single-layer thin film is high near the electrode and decreases as the distance from the electrode increases. Can be cited as one of the following. From the viewpoint of carrier transport ability, it can be said that this concentration gradient type structure has the same ability as the organic multilayer thin film, but the layer configuration can be visually distinguished from the organic multilayer thin film composed of a plurality of layers. . In addition, as a constituent material of the organic single-layer thin film and the organic multilayer thin film, a hole transport material, an organic light-emitting material, and an electron injection material conventionally used in an organic EL element may be used as they are.

Examples of the hole transport material include triazole derivatives, oxadiazole derivatives, imidazole derivatives, phenylenediamine derivatives, arylamine derivatives, pyrazoline derivatives, pyrazolone derivatives, aniline copolymers, polyarylalkane derivatives, stilbene derivatives,
Examples include hydrazone derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, silazane derivatives, and polysilane compounds.

Examples of the organic light emitting material include a benzothiazole compound, a metal chelated oxinoid compound, a stilbenzene compound, an aromatic dimethyl lysine compound, a distilpyrazine derivative benzimidazole compound, and a benzooisazole compound.

Examples of the electron injecting material include heterocyclic tetracarboxylic anhydrides such as nitro-substituted fluorenone derivatives, anthraquinodimethane derivatives, and thiopyrandioiside derivatives, fluorenylidene methane derivatives, oxadiazole derivatives, and 8-quinolinol. Derivatives, carbodiimides,
And anthrone derivatives.

In the present embodiment, the polarizing film 2 and the retardation film λ /
Circularly polarizing film 6 obtained by combining four films 1 is exemplified. FIG. 2 is a diagram schematically illustrating a state in which external light is reflected by the second electrode and a state in which self-luminous light emitted from the electroluminescence layer 4 is emitted to the outside of the electroluminescence element. In the upper part of the drawing, external light enters the electroluminescent element and is reflected by the second electrode for convenience of description. For the sake of convenience, the lower part of FIG. The appearance of light emission outside the electroluminescence element is summarized for convenience of explanation,
Actually, reflection of external light and emission of self-luminous light are performed at the same position in the display surface.

By providing the λ / 4 film 2 functioning as a deflecting rotator between the polarizing film 1 and the electroluminescent layer 3, filtering is performed by the deflecting film 1 before a part of the external light enters the EL element. Is done. The light that has passed through the deflection film 1 without being filtered is λ
The フ ィ ル ム film 2 makes circular polarization in a certain direction. Circularly polarized light in a certain direction is reflected by a reflection film (second electrode 5) constituting the EL element, and becomes circularly polarized light in a direction opposite to the certain direction. When the circularly polarized light in the opposite direction passes through the λ / 4 film 2, it becomes light that cannot pass through the polarizing film 1. Therefore, even if external light enters the EL element and is reflected by the second electrode 5, it cannot exit the EL element.

The self-luminous light of the EL element passes through the λ / 4 film 2 and only a part of the light is filtered by the polarizing film, and the remaining self-luminous light can be emitted outside the EL element.

Therefore, the EL which can prevent the influence of external light
An element can be provided.

As the λ / 4 film, for example, polycarbonate (PC) can be used. For the polarizing film, for example, polyvinyl alcohol (PVA) obtained by mixing triacetyl cellulose (TAC) with a dye or iodine can be used. Further, both films may be a substantially integrated type laminated film laminated to each other.

More specifically, the mechanism will be described below. External light passes through the polarizing film 1 and is converted into vertically linearly polarized light. When the vertically linearly polarized light passes through the λ / 4 film 2, it is converted to left-handed circularly polarized light. The light is reflected by the second electrode 5 and changes in phase to become right-handed circularly polarized light that is counterclockwise to the incident light. When the light passes through the λ / 4 film 2 again, it is horizontally linearly polarized light in the direction orthogonal to the direction of incidence (in FIG. 2, represented by a plurality of points on an arrow)
Is converted to It is prevented from being absorbed by the polarizing film 3 and emitted out of the EL element.

In the above description, the external light before reflection is left-handed circularly polarized light, and the reflected external light is right-handed circularly polarized light. May be clockwise circularly polarized light, and the reflected external light may be clockwise circularly polarized light.

The self-luminous light from the electroluminescent layer is not limited to circularly polarized light filtered by the λ / 4 film, but most of the self-luminous light is λ / 4.
Passes through film 2. The self-luminous light that has passed through the λ / 4 film 2 passes through the polarizing film 1 and goes out of the EL element, but is partially filtered by the polarizing film 1.

With such a mechanism, it is possible to prevent external light that has entered the EL element from being emitted again to the outside.
Since most of the self-emission of the EL element emits light to the outside, glare due to external light is prevented, and only self-emission can be clearly observed.

Therefore, the contrast of the EL device of this embodiment is high.

This embodiment has the following features. That is, as described above, the first electrode 3 is directly provided on the flexible retardation film 2.

Although FIG. 1 shows that the electroluminescent layer 4 is not provided in contact with the retardation film 2, for example, a part of the electroluminescent layer 4 is also provided together with the first electrode 3. May be provided in contact with

In the EL device of this embodiment, the second electrode side is covered with a vapor-deposited film made of a polymer film (not shown) or a sealing film made of a polymer film and an adhesive layer on the second electrode side. Alternatively, the entire EL element may be sealed.

By performing such coating or sealing, the deterioration of the organic single-layer thin film or the organic multilayer thin film containing the light-emitting material made of an organic compound is prevented, and the durability of the EL element against bending is improved.

(Second Embodiment) Next, an EL panel according to a second embodiment will be described. FIG. 3 is a schematic diagram of an EL panel according to the present embodiment. In this EL panel, the direction perpendicular to the paper surface (front and back) is set as the direction in which the observer observes. FIG. 4 is a schematic cross-sectional view taken along line AA ′ of the EL panel of FIG.

The EL panel shown in FIGS.
The electrode and the second electrode have a grid-type matrix electrode in a so-called XY direction. Other configurations are the same as those of the EL device described with reference to FIGS.

As shown in FIG. 3, when the circularly polarizing film 6 is observed from its observation surface, a plurality of band-shaped first electrodes 13a to 13a
It can be seen that 3e are spaced apart and arranged in parallel.
Further, it can be seen that the plurality of band-shaped second electrodes 12a to 12e are arranged in parallel with each other at a distance from each other.

The first and second electrodes are substantially orthogonal. The orthogonal area is a pixel area. That is, the first electrode and the second electrode of the organic EL panel are arranged in a lattice and are matrix electrodes.

As shown in FIG. 4, which is a cross-sectional view taken along line AA ′ of FIG. 3, the first electrodes 13 a to 13 e are provided directly on the λ / 4 film 2 in the direction normal to the display surface D of the electroluminescent layer 4. Have been. Further, the electroluminescence layer 4 is composed of the λ / 4 film 2 and the first electrodes 13a to 13a.
e and directly on both. In addition, the second electrode 12e covers a part of each of the first electrodes 13a to 13e via the electroluminescence layer 4.

The electroluminescence layer 4 may be provided on the entire surface of the λ / 4 film 2. Alternatively, as shown in FIG. 4, the electroluminescence layer 4 may be provided from the center to the end of the λ / 4 film in the AA ′ direction. In that case, a configuration may be provided just below the second electrode 12e. Further, the electroluminescent layer provided immediately below any one of the second electrodes 12a to 12e extends in the BB 'direction orthogonal to the AA' direction and is directly below the other second electrode. May be provided.

Of course, the EL device shown in FIGS. 1 and 2 can be used as a display device, and the EL panel shown in FIGS. 3 and 4 can also be used as a display device. Note that if one pixel described in FIG. 3 is considered to correspond to the electroluminescent element described in FIGS.
It can be said that the panel is a panel in which the electroluminescent elements described in FIGS. 1 and 2 are arranged in a plurality of lattices.

In such an XY matrix panel having a plurality of pixels, the first electrode, the second electrode, and the electroluminescent layer are provided directly on the circularly polarizing film 6, more specifically on the λ / 4 film. Is flexible, and external light entering the EL panel is reflected to
Since it can be prevented from going out of the L panel, the contrast is high.

The driving method of the pixels of this EL panel is as follows.
It is not particularly limited and is selected according to the application.
In any case, any one of the plurality of first electrodes and the second electrodes is independently connected to a driving power source, and each pixel can emit light.

The EL device shown in FIGS.
Is the first electrode of the EL panel described with reference to FIGS.
Or flexible in direct contact with the electroluminescent layer
The coefficient of thermal expansion of the conductive film (substrate) to the preferred numerical range
It is important to specify. For example, its flexible fill
Linear expansion coefficient of 50 × 10^-6/ ℃ or more 100 × 10 ^-6
/ ° C, the flexible film and the first electrode
Can be separated or flexible film and elect
It is not necessary to separate from the luminescence layer. This flexible
Film is a circularly polarized film, and more specifically
Indicates that the first electrode or the electroluminescent layer is directly
The film to be provided, that is, the retardation film in the present embodiment.
Λ / 4 film.

Note that, for example, a transparent plate may be provided on the EL element shown in FIGS. 1 and 2 or the EL panel described with reference to FIGS. 3 and 4. FIGS. 5 and 6 show this state. FIG.
Is a cross-sectional view schematically showing a state in which a transparent plate is provided on the EL element shown in FIG. 1, and FIG. 6 is a cross-sectional view schematically showing a state in which the EL panel transparent plate shown in FIG. 4 is provided.

The transparent plate is a glass plate or a resin plate provided between the electroluminescence layer 4 and the circularly polarizing film 6. In that case, the flexibility of the EL element itself or the EL panel itself is substantially lost, but the strength of the EL element or the EL panel having such a transparent plate is increased due to an external stress such as an impact. Thus, high contrast can be obtained because it is possible to prevent external light that has entered and reflected from the outside from going outside. When using this transparent plate, it is also important to pay attention to the thermal expansion coefficient of the transparent plate.

For example, when the transparent plate is a glass plate, the coefficient of linear expansion is preferably 2 × 10 ⁻⁶ / ° C. or more and 7 × 10 ⁻⁶ / ° C. or less. In this case, the glass plate and the first electrode do not separate from each other, or the glass plate does not separate from the electroluminescent layer.

It is preferable to use, for example, non-alkali glass as the glass substrate. When alkali-free glass is used, even if the first electrode or the electroluminescent layer is brought into contact with the alkali-free glass, the influence of the alkali component can be prevented. Alternatively, a transparent substrate may be used in which the glass surface in contact with the first electrode or the electroluminescent layer is non-alkali glass, and the non-contact portion is glass containing an alkali component. The transparent substrate having such a configuration may have a configuration in which a layer containing an alkali component and a layer not containing an alkali component are stacked, or the concentration of the alkali component in one transparent substrate has a gradient, A configuration may be adopted in which the concentration of the alkali component gradually decreases toward the surface in contact with one electrode or the electroluminescence layer, and the surface is in an alkali-free state.

The glass substrate may be, for example, quartz, borosilicate glass, or soda glass other than alkali-free glass.

[0072]

EXAMPLES In the following examples, examples using an organic compound as an electroluminescent layer will be described.

Example 1 An example of manufacturing an organic EL device will be described in detail with reference to the drawings. The configuration of the organic EL element of this embodiment is the same as that of FIG.

The circularly polarized film described with reference to FIG. 2 was used as a flexible substrate having a size of 30 mm × 30 mm square and a thickness of 0.3 mm. The light transmittance of this film at 400 to 700 nm was about 50%.

A first light-transmitting first film is formed on this film.
A 1500 ° ITO film serving as an electrode was formed by vapor deposition.

The transmittance of the ITO film at a wavelength of 400 to 700 nm was about 90%. In addition, this substrate is
Ultrasonic cleaning for 5 minutes in solution and 5 minutes in pure water respectively
Thereafter, the substrate was washed with a UV ozone washing machine for 10 minutes.

Then, this ITO vapor-deposited film is
1 × 10 ^-FourI in a vacuum of pa
On the TO side, N, N'-bis (3-methyl
Ruphenyl-N, N'diphenyl [1,1'-biphenyl
1) -4,4'-diamine (hereinafter referred to as TPD)
00Å was deposited. Next, quinacridone, a luminescent material,
0 ° was deposited. Next, tris (8-key) which is an electron injection material is used.
Nolinol) aluminum (hereinafter, Alq3) is 500
ÅEvaporated. Next, the second electrode, magnesium and silver
The mixed metal was deposited at 1200 °.

As described above, an ITO film as a light-transparent first electrode and an organic single-layer thin film containing a luminescent material composed of an organic compound or a TPD which is a hole transport material as an organic multilayer thin film are formed on a substrate having polarization characteristics. Quinacridone as a light emitting material, Alq3 as an electron injecting material, and a mixed metal of magnesium and silver as a second electrode.
An L element was obtained. When the reflectivity of the obtained mixed metal of magnesium and silver was measured, it was 7 at a wavelength of 400 to 700 nm.
It was about 0 to 80%.

(Comparative Example 1) Organic EL prepared in Example 1
The following organic EL devices were prepared to compare the device with the contrast.

As the substrate, a transparent polyethylene terephthalate (thickness: 0.3 mm) having a light transmittance of 400% at a wavelength of 400 to 700 nm of 80% was used. Materials, luminescent materials, electron injection materials,
The second electrode was the same as in Example 1 above. Note that this polyethylene terephthalate film does not have retardation characteristics or polarization filtering characteristics.

The contrast of the produced organic EL device was measured as follows.

For the contrast, “contrast = organic E
Luminance at the time of L light emission / Luminance at the time of no organic EL light emission ".

The organic E obtained above was placed 1 m under a fluorescent lamp.
The luminance when the element was made to emit light and the luminance when no light was emitted were compared with the L element. The luminance was measured with a colorimeter. Table 1 shows the results.

[0084]

[Table 1]

As can be seen from Table 1, the organic EL of Example 1
It can be seen that the device has much higher contrast than the organic EL device of Comparative Example 1. In addition, the organic EL device of Example 1 showed clear light emission in which there was a difference between the light emission color and luminance under external light and in a dark room. In addition, sufficient light emission was obtained even when the element was bent. .

Example 2 The electroluminescent layer of the organic EL panel of Example 2 also contains an organic compound as a main component.

The production of the organic EL panel of this embodiment will be described in detail with reference to the drawings.

The circularly polarizing film described with reference to FIG. 2 was used as a flexible substrate having a size of 70 mm × 70 mm square and 0.3 mm thickness. The light transmittance of this film at a wavelength of 400 to 700 nm is about 50%.

On this film, a length of 60 mm × width of 5 mm
Five strip-shaped first electrodes made of an ITO film having a thickness of 1500 mm and a thickness of 1500 mm were provided at intervals of 5 mm in the width direction. This substrate was washed as in Example 1. Next, the first embodiment was applied to the ITO film surface side.
In the same manner as described above, TPD is used as a hole transport material, quinacridone as a light emitting material is laminated thereon by 10 °, and then tris (8-quinolinol) aluminum (hereinafter, referred to as an electron injecting material) is used.
Alq3) was deposited at 500 °. On top of that, 60m long
A stainless steel mask having mx 5 mm width and 5 openings at 5 mm intervals in the width direction was set so as to be orthogonal to the strip-shaped first electrode (ITO film) on a plane. A desired mixed panel of magnesium and silver was deposited at 1200 ° to obtain a desired panel.

FIG. 3 shows a plan view of the obtained organic EL panel. Five first electrodes 13a to 13e made of an ITO film are provided in a strip shape on the surface of a flexible substrate 6 having polarization characteristics, and a hole transporting material TPD film,
Five second electrodes made of a mixed metal of magnesium and silver via a light-emitting material quinacdrine film and an electron injection material Alq3 (illustration of an organic single-layer thin film or an organic multilayer thin film containing a light-emitting material made of these organic compounds is omitted). 12a-12e
Are provided in a strip shape in a direction orthogonal to the first electrode on a plane.

The first electrodes 13a to 13e and the second electrode 12a
The intersection of a to 12e becomes each pixel, and each pixel emits light by the driving driver.

When the contrast of the pixel portion formed in the central portion (3 rows and 3 columns of the XY matrix) of this organic EL panel was evaluated, the contrast was as good as 90% as in Example 1. In addition, even if it was bent to a radius of curvature of about 200 mm, no deterioration in luminance and contrast was observed.

[0093]

As described above, the electroluminescent device of the present invention can prevent visual obscuration due to external light.

Further, the electroluminescent element of the present invention can be deformed into a curved shape by providing an electroluminescent layer on a flexible substrate having polarization characteristics.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one embodiment of an EL device of the present invention.

FIG. 2 is a schematic sectional view illustrating polarization characteristics.

FIG. 3 is a plan view schematically showing an embodiment of the EL panel of the present invention.

FIG. 4 is a schematic cross-sectional view taken along the line AA ′ of the EL panel in FIG. 3;

FIG. 5 is a schematic sectional view in which a transparent plate is provided on the EL element shown in FIG.

FIG. 6 is a schematic cross-sectional view in which a transparent plate is provided on the EL panel shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 polarizing film 2 retardation film (λ / 4 film) 3 first electrode 4 electroluminescent layer 5 second electrode 6 circular polarizing film 12a to 12e second electrode 13a to 13e first electrode 50, 60 transparent plate D electroluminescence Display surface of layer E Surface of λ / 4 film

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Ueno 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 3K007 AB00 AB02 AB04 AB17 BA06 BB00 CA01 CA05 CA06 CB01 CC01 DA00 DB03 EA04 EB00 FA01

Claims (45)

[Claims] 1. An electroluminescence device having at least one surface of an electroluminescence layer as a display surface, comprising: a retardation film; and a deflection film, wherein the retardation film is in a direction normal to the display surface. 3. The electroluminescent device according to claim 1, wherein the device is provided between the electroluminescent layer and the deflection film. 2. The electroluminescent device according to claim 1, wherein a transparent substrate is provided between the electroluminescent layer and the retardation film in a direction normal to the display surface. 3. The electroluminescent device according to claim 2, wherein the transparent substrate is a glass substrate. 4. The electroluminescent device according to claim 2, wherein the transparent substrate is a resin. 5. The electroluminescent device according to claim 1, wherein the retardation film is a λ / 4 film. 6. The electroluminescent device according to claim 1, wherein the electroluminescent layer is a layer containing an organic compound as a main component. 7. The electroluminescent device according to claim 1, wherein the electroluminescent layer is a layer containing an inorganic compound as a main component. 8. A first electrode is provided on a side of the electroluminescence layer on which the retardation film is provided, and a second electrode is provided on a side opposite to the side on which the retardation film is provided. The electroluminescent device according to claim 1, wherein the electroluminescent layer is disposed between the first and second electrodes. 9. The electroluminescent device according to claim 8, wherein a layer thickness value of the first electrode in the normal direction is a thickness value in a range from 500 ° to 6500 °. 10. The electroluminescent device according to claim 8, wherein a layer thickness value of the first electrode in the normal direction is a film thickness value in a range of 500 ° to 5000 °. 11. The electroluminescent device according to claim 8, wherein the first electrode has a transmittance of 550 nm light of 70% or more. 12. The surface roughness of the first electrode is 20 °.
The electroluminescent device according to claim 8, wherein the angle is not less than 500 °. 13. The surface roughness of the first electrode is 50 °.
The electroluminescent device according to claim 8, wherein the angle is not less than 100 °. 14. The electroluminescent device according to claim 8, wherein a layer thickness value of the second electrode in the normal direction is not less than 500 ° and not more than 5000 °. 15. The electroluminescent device according to claim 8, wherein a layer thickness value of the second electrode in the normal direction is 1000 ° or more and 3000 ° or less. 16. The electroluminescent device according to claim 8, wherein the reflectance of the second electrode at 550 nm light is 80% or more. 17. The linear expansion coefficient of the glass substrate is 2 ×
Electroluminescent device according to claim 3, characterized in that 10 ^-6 / ° C. or higher 7 × is 10 ^-6 / ° C. or less. 18. The electroluminescent device according to claim 3, wherein the glass substrate is at least one of alkali-free glass, quartz, borosilicate glass, and soda glass. 19. The method according to claim 3, wherein an alkali-free layer is provided on the surface of the glass substrate on which the electroluminescence layer is provided, and the electroluminescence layer is in contact with the alkali-free layer. Electroluminescent element. 20. The linear expansion coefficient of the retardation film is:
2. The electroluminescent device according to claim 1, wherein the temperature is 50 × 10 ⁻⁶ / ° C. or more and 100 × 10 ⁻⁶ / ° C. or less. 21. The electroluminescent device according to claim 1, wherein the electroluminescent device is a display device of a display device. 22. A first electrode group consisting of a plurality of first electrodes arranged in a stripe pattern and a second electrode group consisting of a plurality of second electrodes arranged in a stripe pattern intersect in plan view. To form an array of matrix electrodes,
The electroluminescent device according to claim 8, wherein a portion where the first electrode and the second electrode intersect in a plan view is a display pixel portion of a display device. 23. An electroluminescent device, wherein at least a part of an electroluminescent layer is provided on at least a surface of a flexible substrate made of a retardation film. 24. The flexible substrate has the retardation film and the deflecting film, and the retardation film is located between the deflecting film and the electroluminescent layer in a direction normal to the surface. The electroluminescent device according to claim 23, wherein the electroluminescent device is arranged. 25. The electroluminescent device according to claim 23, wherein the retardation film is a λ / 4 film. 26. The electroluminescent layer,
The electroluminescent device according to claim 23, wherein the electroluminescent device is a layer containing an organic compound as a main component. 27. The electroluminescent layer,
The electroluminescent device according to claim 23, wherein the electroluminescent device is a layer containing an inorganic compound as a main component. 28. A first electrode is provided on a side of the electroluminescence layer on which the retardation film is provided, and a second electrode is provided on a side opposite to the side on which the retardation film is provided. The electroluminescent device according to claim 23, wherein the electroluminescent layer is arranged between the first and second electrodes. 29. The electroluminescent device according to claim 28, wherein a layer thickness value of the first electrode in the normal direction is a thickness value in a range of 500 ° to 6500 °. 30. The electroluminescent device according to claim 28, wherein a layer thickness value of the first electrode in the normal direction is a film thickness value in a range from 500 ° to 5000 °. 31. The electroluminescent device according to claim 28, wherein the first electrode has a transmittance of 550 nm light of 70% or more. 32. The surface roughness of the first electrode is 20 °
The electroluminescent device according to claim 28, wherein the angle is not less than 500 °. 33. The surface roughness of the first electrode is 50 °.
29. The electroluminescent device according to claim 28, wherein the angle is not less than 100 [deg.]. 34. The electroluminescent device according to claim 28, wherein a layer thickness value of the second electrode in the normal direction is not less than 500 ° and not more than 5000 °. 35. The electroluminescent device according to claim 28, wherein a layer thickness value of the second electrode in the normal direction is not less than 1000 ° and not more than 3000 °. 36. The electroluminescent device according to claim 28, wherein the second electrode has a reflectance of 550 nm light of 80% or more. 37. A linear expansion coefficient of the retardation film is:
The electroluminescent device according to claim 23, wherein the temperature is 50 × 10 ⁻⁶ / ° C. or more and 100 × 10 ⁻⁶ / ° C. or less. 38. The electroluminescent device according to claim 23, wherein the electroluminescent device is a display device of a display device. 39. A first electrode group consisting of a plurality of first electrodes arranged in a stripe and a second electrode group consisting of a plurality of second electrodes arranged in a stripe intersect in plan view. To form an array of matrix electrodes,
29. The electroluminescent device according to claim 28, wherein a portion where the first electrode and the second electrode intersect in a plan view is a display pixel portion of a display device. 40. A method of manufacturing an electroluminescence device having a phase difference film, a first electrode, an electroluminescence layer, and a second electrode, wherein the step of forming the first electrode on a surface of the phase difference film A method of forming the electroluminescent layer on the surface of the retardation film; and a step of forming the second electrode on the surface of the electroluminescent layer. . 41. The method according to claim 40, wherein the retardation film is a resin. 42. The method according to claim 40, wherein the first electrode is an ITO electrode. 43. The step of forming the first electrode comprises an RF
41. The method according to claim 40, wherein the step of forming the first electrode is performed by a magnetron sputtering method. 44. The step of forming the first electrode, comprising:
The method for manufacturing an electroluminescent element according to claim 40, wherein the step is a step of forming the first electrode by a sputtering method. 45. The method according to claim 40, wherein the step of forming the first electrode is a step of forming the first electrode by an ion plating method.