JPH1167446A - Organic electroluminescent element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element capable of preventing the intrusion of moisture and oxygen for a long time securely by setting a sealing compound having a thickness-to-width ratio in a predetermined range by irradiating light converged only on a sealing part formed from the sealing compound and its vicinity, and hardening it. SOLUTION: A sealing compound 16 is coated around a luminous element 15 formed on a board 11 and then, a sealing member 17 is overlaid thereon and thereafter, the sealing compound 16 is hardened so as to bond the board 11 and the sealing member 17 together. In this case, the sealing compound 16 is so coated that the ratio of the thickness (t) to the width (w) of the sealing compound 16 after hardening becomes 1>=(t)/(w)>=0.0001. The sealing compound 16 is hardened as follows: the light from a light source 20 is so converged by way of an optical fiber 21 and a lens system 22 as to have a width approximately equal to that of the sealing compound 16 at the position of the sealing compound 16 made of a photo-curing resin and irradiated on it. The tip of the optical fiber 21 is movable in the direction parallel with the board 11 so that it can irradiate only the region coated with the sealing compound 16 thoroughly and correctly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device and a method of manufacturing the same, and more particularly, to preventing deterioration of the light emitting device due to intrusion of moisture or oxygen and maintaining the performance of the light emitting device stably for a long time. And a method for manufacturing the same.

[0002]

2. Description of the Related Art An organic electroluminescent device has excellent features such as self-emission, thinness, and a wide viewing angle.
It is receiving attention as a display element.

Conventionally, in order to manufacture an organic electroluminescent device, ITO (isodium tin oxide) is formed on a glass substrate.
After forming a transparent conductive film such as by sputtering and patterning to form a lower electrode, this substrate is placed in a vacuum evaporation tank and an organic light emitting layer and an upper electrode are formed by a method such as heating evaporation. Thereafter, a sealing member or the like is fixed to the substrate for the purpose of shielding the light emitting unit from the outside. As the sealing member, glass is generally used, but an organic material having a moisture-proof function or the like may be used (Japanese Patent Application Laid-Open Nos. 7-282975, 8-222368, and 9-7763). , Multiple oxygen
/ Moisture absorption / sealing member is used (Japanese Patent Application Laid-Open
9567, JP-A-7-211455). Also, an adsorbent is inserted between the sealing member and the substrate (Japanese Patent Application Laid-Open No. 9-35868) or filled with an inert gas (Japanese Patent Application Laid-Open Nos. 7-320865 and 8-302340). Have also been tried. As a fixing method of these sealing members, a sealing agent such as an epoxy-based adhesive, a thermosetting resin, a photo-curing resin, or the like is used, using an adhesive function of the sealing member itself.

[0004]

However, the conventional sealing method is not sufficient in preventing moisture and oxygen; the cost is increased due to the use of a large number of sealing members; Bad; In particular, when glass is used as a sealing member, if the glass is used for fixing with a thermosetting resin, the properties of the light emitting element itself are adversely affected by heating for curing, and if the glass is used for fixing with a photocurable resin. There is a problem that the characteristics of the light emitting element are changed by irradiation light for curing. Further, since the moisture permeability of the cured resin is not sufficiently small, there is a problem that the light emitting element is deteriorated due to moisture permeability in a long term.

The present invention solves the above-mentioned conventional problems, and provides an organic electroluminescent device capable of reliably preventing moisture and oxygen from entering for a long period of time without adversely affecting the light emitting device, and a method of manufacturing the same. The purpose is to:

[0006]

According to the organic electroluminescent device of the present invention, a light emitting element portion is disposed between a substrate and a plate-shaped sealing member, and the substrate is sealed with the substrate around the light emitting element portion. In the organic electroluminescent element in which the stop member is sealed with a sealant containing a photocurable resin, the ratio of the thickness t to the width w of the sealant is 1 ≧ t / w ≧ 0.0001, and the sealant is
It is characterized in that it is cured by irradiating the condensed light only on the seal portion and the vicinity thereof with the sealant.

The method for manufacturing an organic electroluminescent device of the present invention comprises:
An organic electroluminescence in which a light emitting element portion is disposed between a substrate and a plate-shaped sealing member, and the substrate and the sealing member are sealed with a sealant containing a photocurable resin in a peripheral portion of the light emitting element portion. In a method for manufacturing an element, an organic electroluminescent element having a step of adhering a sealant containing a photocurable resin to at least one of the substrate and the sealing member and then irradiating the sealant with light to cure the sealant. Wherein the ratio of the thickness t to the width w after curing is 1 ≧ t / w ≧
The method is characterized in that the sealant is adhered so as to have a thickness of 0.0001, and the condensed light is applied to only the adhered portion of the sealant and the vicinity thereof to cure the sealant.

[0008] The ratio of the thickness t to the width w of the sealant is 1 ≧ t /
By setting w ≧ 0.0001, intrusion of moisture or oxygen can be effectively prevented.

Further, in curing the sealant, by irradiating the condensed light only on the portion where the sealant is attached and in the vicinity thereof, it is possible to prevent the performance of the light emitting element portion from being deteriorated due to the light irradiation.

In order to collect the light, it is advantageous to use an optical fiber or to use an optical lens and a mirror in combination.

Further, it is preferable that a series of sealing operations by applying a sealing agent and irradiating light is performed in a dry atmosphere having a water content of 10,000 ppm or less.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an organic electroluminescent device of the present invention and a method for manufacturing the same will be described with reference to the drawings.

First, the light emitting element portion of the organic electroluminescent element of the present invention will be described. Incidentally, a description of general materials used in the following description is described in detail in JP-A-8-236271.

1 to 3 are cross-sectional views schematically showing examples of the structure of a light-emitting element portion of a general organic electric field element used in the present invention, wherein 11 is a substrate, 12 is an anode, 13 is an organic light-emitting layer,
13a represents a hole transport layer, 13b represents an electron transport layer, 13c represents a hole injection layer, 14 represents a cathode, and 15 represents a light emitting element portion.

The substrate 11 serves as a support for the organic electroluminescent element, and is made of a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, or the like.

The anode 12 provided on the substrate 11 plays a role of injecting holes into the organic light emitting layer 13. The anode 12 is usually made of a metal such as aluminum, gold, silver, nickel, palladium, and platinum; a metal oxide such as an oxide of indium and / or tin; a metal halide such as copper iodide; carbon black; It is composed of a conductive polymer such as poly (3-methylthiophene), polypyrrole, and polyaniline. The anode 12 is generally formed by a sputtering method, a vacuum evaporation method, or the like.

Organic light emitting layer 13 provided on anode 12
Is formed of a material that efficiently transports and recombines holes injected from the anode and electrons injected from the cathode between electrodes to which an electric field is applied, and emits light efficiently by the recombination. Usually, the organic light emitting layer 13 is provided with a hole transport layer 13a as shown in FIG.
And the electron transport layer 13b to obtain a function-separated type (Appl. Phys. Lett., 51, 913, 1987).
Year).

In the above function-separated element, the conditions required for the material of the hole transport layer 13a are that the hole injection efficiency from the anode 12 is high and that the injected holes are transported efficiently. What can be done.

The hole transport layer 13a is formed by laminating the above hole transport material on the anode 12 by a coating method or a vacuum evaporation method. The thickness of the hole transport layer 13a is
Usually, it is 10 to 300 nm, preferably 30 to 100 nm. In order to uniformly form such a thin film, generally, a vacuum deposition method is often used.

In order to improve the contact between the anode 12 and the hole transport layer 13a, a hole injection layer 13c may be provided between the anode 12 and the hole transport layer 13a as shown in FIG. The material used for the hole injection layer 13c can form a uniform thin film with good contact with the anode 12 and is thermally stable, that is, has a high melting point and a high glass transition temperature, a melting point of 300 ° C. or higher, and a glass transition temperature of 300 ° C. or higher. As the temperature
100 ° C or higher is required.

The hole injection layer 13c can be formed into a thin film in the same manner as the hole transport layer 13a. However, when the material for forming the hole injection layer 13c is an inorganic material, the hole injection layer 13c can be further formed by sputtering or electron beam evaporation. The plasma CVD method is used. The thickness of the hole injection layer 13c is usually 3 to 100 nm, preferably 10 to 100 nm.
5050 nm.

The electron transport layer 13 is provided on the hole transport layer 13a.
b is provided. The electron transport layer 13b is formed of a compound capable of efficiently transporting electrons from the cathode 14 between the electrodes to which an electric field is applied in the direction of the hole transport layer 13a.

As described above, the electron transporting compound used in the electron transporting layer 13b must be a compound having a high electron injection efficiency from the cathode 14 and capable of efficiently transporting the injected electrons. It is. For that purpose, the electron affinity is large, the electron mobility is large,
Further, the compound is required to be a compound which has excellent stability and hardly generates impurities serving as a trap during production or use.

The electron transporting layer 13b can be formed in the same manner as the hole transporting layer 13a, but usually, a vacuum evaporation method is used. The film thickness of the electron transport layer 13b is usually 10 to
It is 200 nm, preferably 30-100 nm.

The cathode 14 plays a role of injecting electrons into the organic light emitting layer 13. As the cathode forming material, the anode 1
Although it is possible to use the material used for No. 2, for efficient electron injection, a metal having a low work function is preferable, and tin, magnesium, indium, calcium,
A suitable metal such as aluminum or silver or an alloy thereof is used. The thickness of the cathode 14 is usually the same as that of the anode 2. To protect the cathode made of a low work function metal, it is effective to further stack a metal layer having a high work function and being stable to the atmosphere to increase the stability of the device.
For this purpose, metals such as aluminum, silver, nickel, chromium, gold, platinum and the like are used.

FIGS. 1 to 3 show an example of a light emitting element section according to the present invention, and the present invention is not limited to those shown in the drawings. For example, the reverse structure of FIG.
That is, the cathode 14, the organic light emitting layer 13, and the anode 1
It is also possible to laminate in the order of 2, and as described above, it is also possible to provide such a light emitting element portion between two substrates, at least one of which has high transparency. Similarly, FIG.
And it is also possible to laminate | stack in the structure opposite to the said each layer structure shown in FIG.

Next, a sealing method according to the present invention will be described with reference to FIGS.

FIG. 4 is a perspective view showing a state in which a sealant is applied to a substrate on which a light emitting element portion is formed, and FIG. 5 is a sectional view showing a state in which a sealing member is fixed to the substrate.

First, as shown in FIG. 4, a substrate 11 on which a light emitting element portion 15 comprising an anode, an organic light emitting layer and a cathode is formed.
A sealing agent 16 is applied around the light emitting element portion 15 of FIG. 5, and then, as shown in FIG.
The sealing agent 16 is cured to fix the substrate 11 and the sealing member 17 together.

The performance required of the sealant 16 is as follows:
The permeability of oxygen and moisture is low, the adhesion to the substrate 11 and the sealing member 17 is high, and application is easy.

In the present invention, as the sealant 16,
An epoxy or acrylic photocurable resin, preferably an epoxy photocurable resin is used. Note that, in the present invention, the photocurable resin is a resin that requires at least light irradiation for curing, and is not limited to one that cures only by light irradiation. It also includes those that perform the reaction to promote the reaction.

As the sealing member 17, a glass plate,
An acrylic substrate or film such as PMMA (polymethyl methacrylate), a polycarbonate substrate or film, a transparent or translucent resin substrate or film such as a polyolefin substrate or film, preferably a glass plate can be used. In case of 0.1 ~
It is about 2.0 mm. This sealing member may be a resin substrate or a film to which a gas barrier property against oxygen, water, or the like is added. In this case, the gas barrier property is realized by depositing silicon oxide (SiO _x ) or the like. it can. Note that the sealing member does not necessarily need to be transparent or translucent, and it is sufficient that at least one of the substrate of the organic electroluminescent element and the sealing member is transparent or translucent.

The sealing agent 16 is generally applied to the peripheral portion of the light emitting element portion 15 of the substrate 11 by sequentially applying a material extruded from a pressurized syringe or by applying a screen printing method through a mask. Is attached.

In the present invention, the cured sealant 16
The sealant is applied such that the ratio of the thickness t to the width w satisfies 1 ≧ t / w ≧ 0.0001, preferably 0.1 ≧ t / w ≧ 0.001. If the width w is too large, the sealing area occupying the entire substrate becomes large, which is not practical. If the width w is too small, the performance of preventing the permeation of oxygen and moisture cannot be sufficiently obtained. On the other hand, if the thickness t is too large, the cross-sectional area through which oxygen or moisture permeates becomes large, so that sufficient waterproof and oxygen-proof performance cannot be obtained. is there. It is preferable that the distance s between the light emitting element portion 15 and the application portion of the sealant 16 is about 0.5 to 20 times the width w of the sealant. If the interval s is too large, the surplus area occupying the entire substrate becomes large, which is not practical. If the interval s is too small, the sealant and the light emitting element portion become too close to each other, and the light emitting element portion is hardened during the curing treatment of the sealant. Easily affected. The sealing surfaces of the substrate and the sealing member may be flat as shown in FIG. 5, or may have regular or irregular irregularities.

FIG. 6 is a sectional view showing an example of a seal portion having regular irregularities. Regular rectangular irregularities 11A and 17A are provided on the sealing surfaces of the substrate 11 and the sealing member 17. These irregularities 11A and 17A mesh with each other to seal with the sealant 16 therebetween. In such a shape,
The substantial sealing area can be increased without increasing the sealing area occupying the entire substrate, which is effective in improving the sealing strength.

FIG. 7 is a plan view of a seal portion of a substrate showing an example of a seal portion having irregular irregularities, and FIG. 8 is a sectional view showing a seal portion using this substrate. Substrate 11
And a substantially spherical projection 11 on the sealing surface of the sealing member 17.
B and 17B are provided irregularly, respectively, and mesh with each other to seal with the sealant 16 interposed therebetween. Even with such a shape, a good sealing effect can be obtained as in the case of FIG.

When such irregularities are provided on the sealing surface, the ten-point average roughness R according to JIS B0601 is used.
It is preferable that z is about 0.1 to 20 μm. If the surface roughness is less than 0.1 μm, the effect of improving the sealing effect due to the formation of the unevenness is not sufficient. If the surface roughness exceeds 100 μm, the surface becomes too rough and the sealing performance may be reduced. Even when the seal surface is provided with irregularities, the thickness t and the width w of the sealant taking this surface roughness into account.
So that the ratio t / w to the above range is in the above range.

Next, a method of sealing by the method of the present invention using a photocurable resin as a sealant and a glass plate as a sealing member will be described.

FIG. 9 is a schematic sectional view showing a sealing method using an optical fiber, and FIG. 10 is a schematic sectional view showing a sealing method using an optical lens and a mirror. Figures 9 and 1
At 0, 20 denotes a light source, 21 denotes an optical fiber, 22 denotes a lens system, 23 denotes an optical path, 24 denotes a lens, and 25 denotes a mirror.

In the method shown in FIG. 9, the light emitted from the light source 20 passes through the optical fiber 21 for waveguide and the lens system 22 for light collection. Light emitted from the lens system 22 is applied to the sealant 16 made of a photocurable resin,
The light is condensed and irradiated to the same extent as the width of 6. Optical fiber 2
The front end portion 1 is movable in the horizontal direction with respect to the substrate 11, so that only the application region of the sealant 16 can be accurately irradiated with light. In addition, the irradiation light amount and the moving speed can be arbitrarily set, and control can be performed in accordance with the curing conditions of the photocurable resin of the sealant.

In the method shown in FIG. 10, the light emitted from the light source 20 is condensed by the lens 24 and reflected by the mirror 25 to reach the sealant 16. Here, the light emitted from the light source 20 is
The light is condensed by the lens 24 to the same extent as the width of the sealant 16. The mirror 25 is designed so that the reflection angle of light can be freely changed, and thereby, it is possible to accurately irradiate light only to the application region of the sealant. Further, the irradiation light amount and the moving speed of the mirror can be arbitrarily set, and can be controlled according to the curing conditions of the photocurable resin.

It is preferable that the light irradiated to the seal portion is focused at the irradiation position so that the diameter of the spot is 1 to 10 times the width w of the sealant.

Further, from the viewpoint of easily applying the photocurable resin as a sealant at an application amount that satisfies the above-mentioned t / w ratio, the viscosity of the sealant before curing is 1 to 10,000 Pa · s. Preferably, there is.

In the present invention, in order to prevent the light emitting element from being deteriorated by moisture or oxygen during the sealing operation, a series of sealing operations from application of the sealing agent to curing are performed with a water content of 10,000 p.m.
The sealing is preferably performed in a dry atmosphere of pm or less, particularly 1 ppm or less, and practically, the sealing operation is preferably performed in a dry box filled with an inert gas such as nitrogen or argon.

The organic electroluminescent device shown in FIGS. 1 to 10 and the sealing method thereof are examples of the present invention, and do not limit the present invention. Various other aspects can also be adopted as a device used for the shape and curing of the seal portion.

[0046]

Next, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

Example 1 First, an organic electroluminescent device having the structure shown in FIG. 3 was manufactured by the following method.

A Corning 1737 glass having a thickness of 1.1 mm was used as the glass substrate 11, and an I
A TO transparent conductive film was deposited to a thickness of 120 nm (manufactured by Geomatic Corporation; electron beam film-formed product; sheet resistance: 20Ω) to obtain a glass substrate with an ITO film. At this time, the surface of the glass substrate is flat including the sealing portion (Rz <10 nm; Rz: 10-point average roughness (JISB0
601)) was adopted.

The ITO transparent conductive film deposited on the glass substrate 11 is formed into a stripe having a line width of 2 mm by using a usual photolithography technique and hydrochloric acid etching.
And The patterned ITO substrate is cleaned in the order of ultrasonic cleaning with acetone, water cleaning with pure water, and ultrasonic cleaning with isopropyl alcohol, dried with nitrogen blow, and subjected to ultraviolet / ozone cleaning for 10 minutes. 1.1 × 10 ^-6 Torr using a cryopump
(About 1.5 × 10 ⁻⁴ Pa).

Next, the following copper phthalocyanine (H1) was placed in a molybdenum boat placed in a vacuum evaporation tank.
(The crystal form was β-form) was heated to perform vapor deposition. Vacuum degree 1.1
Vapor deposition was performed at × 10 ⁻⁶ Torr (about 1.5 × 10 ⁻⁴ Pa) for a deposition time of 1 minute to obtain a hole injection layer 13c having a thickness of 20 nm.

[0051]

Embedded image

Next, the following 4,4′-bis [N-butane] was placed in a ceramic crucible similarly arranged in a vacuum evaporation tank.
(1-Naphthyl) -N-phenylamino] biphenyl (H2)
Was heated with a tantalum wire heater around the crucible and laminated on the hole injection layer 13c. The temperature of the crucible at this time is
The temperature was controlled in the range of 230 to 240 ° C. Vacuum degree during evaporation 8 x 10
^-7 Torr (approximately 1.1 × 10 ^-4 Pa), deposition time 1 minute 50 seconds and film thickness 60
A hole transport layer 13a having a thickness of nm was obtained.

[0053]

Embedded image

Next, the electron transport layer 13b having a light emitting function
As a material of the compound, aluminum 8-hydroxyquinoline complex represented by the following structural formula Al (C ₉ H ₆ NO) ₃ (E1)
Was similarly deposited on the hole transport layer 13a. At this time, the temperature of the crucible was controlled in the range of 310 to 320 ° C. The degree of vacuum during vapor deposition is 9 × 10 ⁻⁷ Torr (about 1.2 × 10
^-4 Pa), the deposition time was 2 minutes and 40 seconds, and the thickness of the deposited electron transport layer 13b was 75 nm.

[0055]

Embedded image

The above-described hole injection layer 13c and hole transport layer 13
The substrate temperature when vacuum-depositing the electron transport layer 13a and the electron transport layer 13b was kept at room temperature.

Next, in a vacuum chamber, a shadow mask having a stripe-shaped hole having a width of 2 mm was placed on a substrate on which an organic layer was deposited so that the longitudinal direction of the hole was perpendicular to the line of the patterned anode 12. Placed before. Thereafter, as a cathode 14, an alloy electrode of magnesium and silver was deposited by a dual simultaneous evaporation method so as to have a thickness of 100 nm. Vapor deposition was performed using a molybdenum boat and the degree of vacuum was 1 × 10 ⁻⁵ Torr (about 1.3 × 10 ⁻³ Torr).
Pa) with a deposition time of 3 minutes and 10 seconds. The atomic ratio of magnesium to silver was 10: 1.2. Then, in a vacuum evaporation tank, aluminum was
The cathode 14 was completed by laminating on a magnesium-silver alloy film with a thickness of 100 nm. The degree of vacuum during aluminum deposition
2.3 × 10 ^-5 Torr (about 3.1 × 10 ^-3 Paa), deposition time is 1 minute
40 seconds. The substrate temperature at the time of vapor deposition of the two-layered cathode of magnesium / silver alloy and aluminum was kept at room temperature.

Next, the substrate having been formed up to the cathode was moved into a dry box (water content: 1 ppm) filled with nitrogen gas to perform a sealing operation. First, as shown in FIG. 4, an epoxy-based photocurable resin (viscosity: 45 Pa · s, curing condition: 4000 mJ / cm ² ) is provided around the light emitting element portion 15 of the element at a distance of 2 mm (s = 2 mm in FIG. 5). ) And a width of 1 mm (w = 1 mm in FIG. 5). Here, the electrode extraction portions of the anode and the cathode were arranged outside the seal. next,
As shown in FIG. 5, a glass plate having a thickness of 0.7 mm is placed as a sealing member, and then, as shown in FIG.
The light was condensed on a spot of 5 mm and irradiated onto the sealing material of the photocurable resin through the sealing member, and the sealing part was rotated at a speed of 2 cm per second. This irradiation completely cured the photocurable resin.

Then, the device was taken out of the dry box to obtain an organic electroluminescent device having a size of 2 mm × 2 mm. At this time, the thickness of the seal portion is 20 μm, and the thickness of the seal portion is
The ratio t / w between t and width W was 0.02.

When a positive electrode was connected to the anode 12 and a negative electrode was connected to the cathode 14 and a direct current of 15 mA / cm ² was applied to the device, the voltage was 8.5 V and the light emission luminance was 1250 cd / m ² . When the device was continuously driven under the same conditions, it took 2780 hours for the luminance to be reduced to half.

Example 2 An element was manufactured in the same manner as in Example 1 except that the sealing portions of the substrate 11 and the sealing member 17 were roughened in advance. The flatness of the sealing portions of the substrate 11 and the sealing member 17 was both 1.2 μm in Rz value.

The apparent width of the sealing portion of this element is 1 mm,
The apparent thickness was 20 μm, which was the same as in Example 1. However, from the influence of the fine irregularities of the seal portion, it is estimated that the substantial thickness / width ratio t / w of the seal portion is smaller than 0.02. The effective t / w ratio estimated from the value of the surface roughness Rz is
It was 0.005.

This device was charged with 15 mA / c in the same manner as in Example 1.
When a DC current of m ² was applied, the voltage was 8.4 V and the light emission luminance was 1230 cd / m ² , almost the same results as in Example 1. Next, when the device was continuously driven under the same conditions, the time during which the luminance was reduced to half was 3360 hours, which was longer than in Example 1.

Example 3 Up to the cathode 14, the same method as in Example 1 was used, and then sealing was performed in the following manner.

First, the substrate on which the formation of the cathode was completed was moved into a dry box (water content: 1 ppm) filled with nitrogen gas, and an epoxy-based photocurable resin similar to that of Example 1 was placed around the light emitting element portion. Was applied with a width of 0.2 mm at an interval of 2 mm. At the time of coating, in order to increase the thickness, the coating speed was lower than that in Example 1. Thereafter, the sealing member was placed in the same manner as in Example 1, and only the sealing agent portion of the photocurable resin was irradiated with light to completely cure the sealing agent.

Thereafter, the device was taken out of the dry box to obtain an organic electroluminescent device having a size of 2 mm × 2 mm. At this time, the ratio t / w between the thickness and the width of the seal portion was 0.2.

This device was charged with 15 mA / c in the same manner as in Example 1.
When a DC current of m ² was applied, the voltage was 8.4 V, the light emission luminance was 1220 cd / m ² , and almost the same good results as in Example 1 were obtained. Next, when the device was continuously driven under the same conditions, the time when the luminance was reduced to half was 2540 hours.

Comparative Example 1 An organic electroluminescent device was manufactured in the same manner as in Example 3 except that the ratio t / w of the thickness and the width of the seal portion was set to 2.0.

This device was charged with 15 mA / c in the same manner as in Example 1.
When a DC current of m ² was applied, the voltage was 8.6 V, and the emission luminance was 1190 cd / m ² , which was almost the same good result as in Example 1. However, when the element was continuously driven under the same conditions, the luminance was increased. The time to halve was significantly inferior to 1140 hours.

Comparative Examples 2 and 3 For comparison, up to the cathode 14, the same method as in Example 1 was used, and then sealing was performed by the following method.

First, the substrate on which the formation up to the cathode was completed was moved into a dry box filled with nitrogen gas, and the same epoxy-based photocurable resin as in Example 1 was applied around the light emitting element portion.
It was applied at a width of 0.2 mm with an interval of 2 mm. Next, Example 1
After the same sealing member was fixed, the entire surface of the element including the photocurable resin portion was irradiated with light from the sealing member side using a conveyor-type ultraviolet light irradiator to completely cure the sealant. The irradiation light amount at this time was the same as in Example 1.

Thereafter, the device was taken out of the dry box, and an organic electroluminescent device having a size of 2 mm × 2 mm was obtained.
At this time, the ratio t / w between the thickness and the width of the seal portion was 0.02 (Comparative Example 2) or 2.0 (Comparative Example 3).

This device was charged with 15 mA / c in the same manner as in Example 1.
When a DC current of m ² was applied, the voltage was increased to 12.3 V, and the emission luminance was as low as 580 or 565 cd / m ² . next,
When the device was continuously driven under the same conditions, the time when the luminance was reduced to half was as short as 1870 or 730 hours.

Table 1 shows the results of the emission characteristics of Examples 1 to 3 and Comparative Examples 1 to 3. Note that the above comparative example 1
In Comparative Example 3, in order to set t / w = 2.0, the application speed was slower than that in Example 1 when applying the photocurable resin, and the application thickness was increased to 400 μm.

[0075]

[Table 1]

[0076]

As described above in detail, according to the present invention, the ratio t / W of the thickness and the width of the sealant of the organic electroluminescent device is set to 1 to
By setting the value to 0.0001, it is possible to efficiently suppress the entry of moisture and oxygen, which is one of the causes of performance degradation of the element. Furthermore, by using a photocurable resin as the sealant and irradiating only the seal portion with light to cure the sealant, deterioration of the performance of the element due to ultraviolet light irradiation can be prevented.

Therefore, the organic electroluminescent device according to the present invention can be applied to a high-performance flat panel display (for example, for an OA computer, a portable terminal, a flat-screen television, etc.), and its technical value is large. is there.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a layer configuration of an organic electroluminescent device.

FIG. 2 is a schematic cross-sectional view showing another example of the layer configuration of the organic electroluminescent element.

FIG. 3 is a schematic cross-sectional view showing another example of the layer configuration of the organic electroluminescent element.

FIG. 4 is a schematic perspective view showing a method of applying a sealant around a light emitting element unit.

FIG. 5 is a schematic cross-sectional view showing a seal portion sandwiched between a substrate and a sealing member.

FIG. 6 is a schematic cross-sectional view showing another example of the seal portion.

FIG. 7 is a schematic plan view showing a sealing surface of a substrate.

FIG. 8 is a schematic cross-sectional view showing another example of the seal portion.

FIG. 9 is a schematic sectional view showing an example of a light irradiation method.

FIG. 10 is a schematic sectional view showing another example of the light irradiation method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Substrate 12 Anode 13 Organic light emitting layer 13a Hole transport layer 13b Electron transport layer 13c Hole injection layer 14 Cathode 15 Light emitting element part 16 Sealant 17 Sealing member 20 Light source 21 Optical fiber 22 Lens system 23 Optical path 24 Lens 25 Mirror

Claims (5)

[Claims] 1. A light emitting element portion is disposed between a substrate and a plate-shaped sealing member, and the substrate and the sealing member are sealed with a sealant containing a photocurable resin in a peripheral portion of the light emitting element portion. In the manufactured organic electroluminescent device, the ratio of the thickness t to the width w of the sealant is 1 ≧ t / w ≧ 0.0001
An organic electroluminescent device, wherein the sealing agent is cured by irradiating light condensed only on the sealing portion and the vicinity of the sealing portion with the sealing agent. 2. A light emitting element portion is disposed between a substrate and a plate-shaped sealing member, and the substrate and the sealing member are sealed with a sealant containing a photocurable resin in a peripheral portion of the light emitting element portion. In a method of manufacturing the organic electroluminescent device, a step of attaching a sealant containing a photocurable resin to at least one of the substrate and the sealing member, and then irradiating the sealant with light to cure the sealant. In the method for producing an organic electroluminescent device, the ratio of the thickness t to the width w after curing of the sealant is 1 ≧ t /
A method for manufacturing an organic electroluminescent device, comprising: attaching the sealing agent so as to satisfy w ≧ 0.0001, and irradiating the condensed light only to the portion where the sealing agent is attached and the vicinity thereof to cure the sealing agent. 3. The method according to claim 2, wherein light is irradiated using an optical fiber. 4. The method according to claim 2, wherein light is irradiated using an optical lens and a mirror. 5. The method according to claim 2, wherein the adhesion of the sealant and the irradiation of light are performed with a water content of 1000.
A method for producing an organic electroluminescent device, which is performed in a dry atmosphere of 0 ppm or less.