JP2001237066A - Organic electroluminescent device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent device and manufacturing method of the same, affixing a sealing plate restraining the expansion of dark spot with the passage of time, efficiently and surely. SOLUTION: An adhesive agent part is heated efficiently with laser radiation and the like by making an adhesive agent for sealing, adhering a base plate and a sealing plate, contain a photothermal conversion material. Accordingly, even in the case of using a heat-hardening type adhesive agent, a luminous layer part of the organic electroluminescent device can be sealed without thermal deterioration.

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 that can be used in fields such as display elements, flat panel displays, backlights, and interiors.

[0002]

2. Description of the Related Art An organic electroluminescent device emits light by recombination of holes injected from an anode and electrons injected from a cathode in an organic light emitting layer sandwiched between both electrodes. A typical structure is to stack a transparent first electrode (anode), hole transport layer, organic luminescent layer, and second electrode (cathode) on a glass substrate, and then seal it with a thin glass plate or other sealing plate. Light emission generated by the driving is extracted to the outside through the first electrode and the glass substrate. Such an organic electroluminescent device is capable of emitting thin, high-luminance light under low-voltage driving, and multicolor light emission by selecting an organic light-emitting material, and is applied to light-emitting devices and displays.

One of the problems in the organic electroluminescent device is that the area of a non-light-emitting portion called a dark spot increases with time. It is known that the cause of such characteristic deterioration is moisture.
That is, moisture enters the organic thin film due to a defect of the second electrode or the like, and partially inactivates the element.

In order to prevent such dark spots from expanding, it is necessary to keep the organic electroluminescent device under a low humidity atmosphere. For this reason, a method has been used in which the light emitting region is sealed with a sealing plate and an adhesive, the sealed internal space is kept in a vacuum, or a low humidity inert gas or oil is filled. In these methods, penetration of moisture from the outside to the inside of the sealing can be suppressed by selecting a preferable adhesive or the like. Further, as a means for attaching the sealing plate, a method of applying an adhesive to the outer peripheral portion of the light emitting region and fixing the sealing plate on the substrate is used.

[0005]

On the other hand, the heat resistance of a thin film layer including a light emitting layer made of an organic compound is not high, and can generally only withstand a temperature of about 100 to 120 ° C. Therefore, a resin or the like that cures at a high temperature for sealing cannot be used.
Liquid mixed type resins and the like have been used. However, in order to improve the storage stability of the organic electroluminescent device under high temperature and high humidity, it has become necessary to use a sealing adhesive having a high curing temperature.

[0006]

That is, the present invention provides a first electrode formed on a substrate, a thin film layer formed on the first electrode, the light emitting layer comprising at least an organic compound, and a thin film layer formed on the thin film layer. An organic electroluminescent device including a second electrode, and a sealing plate attached to a substrate with an adhesive, wherein the adhesive contains a photothermal conversion material. .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is directed to an organic light emitting device having an arbitrary structure regardless of the type of light emitting device such as a single light emitting device, a segment type, a simple matrix type, and an active matrix type, and the number of colors of light emission such as color and monochrome. Applied to electroluminescent devices.

The present invention relates to the mounting of a sealing plate with an adhesive. According to the present invention, the adhesive can be concentrated and efficiently heated by laser irradiation or the like. The sealing can be performed without damaging the light emitting layer.

The organic electroluminescent device of the present invention preferably has the form shown in FIGS. 1 to 4, but is not particularly limited. A first electrode 2 having a transparent film of indium tin oxide (ITO) formed on a surface of a substrate 1 such as glass is formed, a hole transport layer 5 made of an organic compound, a light emitting layer 6 and the like are formed, and a second electrode 8 is formed. Then, an organic electroluminescent device is manufactured. Thereafter, sealing is performed by bonding a sealing plate 21 made of a material such as glass to the substrate 1 via an adhesive 22 containing a photothermal conversion material. Further, the driving system 3 is connected to obtain an organic electroluminescent device. If necessary, a protective layer 9 for protecting each organic layer may be provided.

As the sealing plate, a plate or film formed of a material having low moisture permeability, such as glass, resin, or metal, can be used. These may be a single type or a composite type obtained by depositing a metal such as aluminum on a resin film such as polyethylene.

The shape of the sealing plate is not particularly limited. For example, a concave portion 24 is formed as shown in FIG. 3 or a leg 25 is formed as shown in FIG. The bonding position can also be defined. By doing so, it is also possible to secure a volume for filling the sealing internal space 23 with gas or oil or for providing a moisture absorbent. The same effect can be obtained by increasing the thickness of the adhesive. In addition, a getter film or the like having a moisture absorbing effect or a black film or a light absorbing film having an antireflection effect can be formed on the surface of the sealing plate in advance. As the hygroscopic agent, silica gel, zeolite, activated carbon, calcium oxide, germanium oxide, barium oxide, magnesium oxide, phosphorus pentoxide, calcium chloride, etc., as the getter film, aluminum, magnesium,
A metal vapor-deposited film of barium, titanium, or the like can be given as an example.

The bonding position between the substrate and the sealing plate is not particularly limited, and the bonding agent may be positioned so as to cover the entire device. However, from the viewpoint of light emission stability, the bonding agent is in contact with the light emitting region. It is preferable that they are not located. further,
From the viewpoint of handling, it is preferable that each of the first electrode and the second electrode is sealed so as to be exposed to the outside.

The adhesive for bonding the substrate and the sealing plate of the organic electroluminescent device of the present invention needs to contain a light-to-heat conversion material because it is selectively heated and cured by irradiating a laser beam. As the adhesive, a curable resin or a plastic resin is preferably used because a large effect can be obtained relatively easily without requiring a high-temperature process of 200 ° C. or higher. As the curable resin material, a known material such as an epoxy-based, silicone-based, acrylic-based, or urethane-based material can be used. At this time, a photothermal conversion material having an absorption region corresponding to the wavelength of the laser beam to be used may be appropriately selected and used.

The photothermal conversion material used in the present invention includes, for example, black pigments such as carbon black, aniline black and cyanine black, phthalocyanine and naphthalocyanine green pigments, carbon graphite, iron powder, diamine metal complex and dithiol metal complex. Complexes, phenol thiol metal complexes, mercaptophenol metal complexes, inorganic compounds containing water of crystallization, copper sulfate, chromium sulfide, silicate compounds, titanium oxide, vanadium oxide, manganese oxide, iron oxide, cobalt oxide, tungsten oxide, etc. It is preferable to add additives such as metal oxides, hydroxides and sulfates of these metals, and metal powders of bismuth, iron, magnesium, and aluminum. Among these, carbon black is more preferred from the viewpoint of light-to-heat conversion rate, economic efficiency and handleability.

In addition to the above substances, dyes that absorb infrared or near-infrared rays are also preferably used as photothermal conversion substances.

These dyes are 400 to 1200 nm.
Any dye having a maximum absorption wavelength in the range of nm can be used. Preferred dyes include those for electronics,
Recording dyes cyanine, phthalocyanine, phthalocyanine metal complex, naphthalocyanine, naphthalocyanine metal complex, dithiol metal complex, naphthoquinone, anthraquinone, indophenol, indoaniline, pyrylium, thiopyrylium , Squarylium, croconium, diphenylmethane,
Triphenylmethane, triphenylmethanephthalide, triallylmethane, phenothiazine, phenoxazine, fluoran, thiofluorane, xanthene, indolylphthalide, spiropyran, azaphthalide, chromenopyrazole, Leuco auramine, rhodamine lactam, quinazoline, diazaxanthene, bislactone, fluorenone, monoazo, ketone imine, diazo, polymethine, oxazine, nigrosine, bisazo, bisazostilbene, bis Azooxadiazole, bisazofluorenone, bisazohydroxyperinone, azochrome complex, trisazotriphenylamine, thioindigo, perylene, nitroso, 1: 2 type metal complex,
Intermolecular CT, quinoline, quinophthalone, fulgide acid dyes, basic dyes, dyes, oil-soluble dyes, triphenylmethane leuco dyes, cationic dyes, azo disperse dyes, benzothiopyran spiropyran, 3, 9-
Examples include dibromoanthanthrone, indanthrone, phenolphthalein, sulfophthalein, ethyl violet, methyl orange, fluorescein, methyl viologen, methylene blue, dimrosbetaine and the like.

Of these, dyes for electronics and recording, having a maximum absorption wavelength of 700 nm to 900 nm
m, cyanine dye, azulenium dye, squarylium dye, croconium dye, azo disperse dye, bisazostilbene dye, naphthoquinone dye, anthraquinone dye, perylene dye, phthalocyanine dye, na Phthalocyanine metal complex dyes,
Polymethine dyes, dithiol nickel complex dyes, indoaniline metal complex dyes, intermolecular CT dyes, benzothiopyran spiropyrans, nigrosine dyes and the like are preferably used.

Further, among these dyes, those having a large molar absorbance coefficient are preferably used. Specifically, ε = 1 × 10 4 or more is preferable, and 1 × 1 is more preferable.
05 or more. When ε is smaller than 1 × 10 4, the effect of improving the heat conversion efficiency is hardly exhibited.

These light-to-heat conversion substances alone have an effect of improving heat conversion efficiency, but the heat conversion efficiency can be further improved by using two or more kinds in combination. In addition, by using two or more kinds of photothermal conversion materials having different absorption wavelengths together, it is possible to cope with two or more kinds of lasers having different transmission wavelengths.

The content of these light-to-heat converting substances is preferably from 0.1 to 40% by weight, more preferably from 0.5 to 25% by weight, based on the whole adhesive composition. When the amount is less than 0.1% by weight, the effect of improving the heat conversion efficiency with respect to the laser beam is not obtained, and when the amount is more than 40% by weight, the sealing performance of the adhesive is likely to deteriorate.

The laser light source used in the heat curing step of the present invention has an emission wavelength range of 300 nm to 1500.
Those in the range of nm are used. At this time, the wavelength of the laser beam may be any wavelength in the ultraviolet, visible, and infrared regions, that is, argon ion, krypton ion, helium-neon, helium-cadmium, ruby, glass, YAG, Titanium sapphire, dye, nitrogen, metal vapor, excimer (for example, Xe, Cl,
Various lasers such as KrF and ArF), free electrons and semiconductors are used.

Among these, a semiconductor laser having an emission wavelength region near the near infrared region is preferably used for the purpose of curing the adhesive of the present invention.

The output of the laser beam may be any as long as the adhesive of the present invention can be cured. When the output of the laser beam itself is small, it can be cured by lengthening the processing time. The laser light emitted from the oscillator may be used as it is, or the light intensity may be increased by condensing the light using a lens.

The method for manufacturing an organic electroluminescent device according to the present invention comprises:
The outline is as follows, but is not limited thereto. A first electrode is formed by patterning an ITO substrate on which a transparent film of indium tin oxide (ITO) formed on a glass substrate surface by a sputtering method or the like is formed by a photolithography method, and then a thin film including a light emitting layer made of at least an organic compound A layer is formed, a second electrode is formed, and an organic electroluminescent device is manufactured. Thereafter, sealing is performed by attaching a sealing plate made of a material such as glass to the substrate. In the sealing step, an adhesive containing a light-to-heat conversion material is applied so as to surround the light-emitting region of the element, and a sealing plate is arranged facing the substrate with the adhesive layer interposed therebetween, and is bonded. Then, the adhesive is selectively heated and cured to bond the substrate and the sealing plate to obtain an intended organic electroluminescent device.

[0025]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 A 130 nm thick ITO film was formed on a 1.1 mm thick Corning 7059 glass surface by sputtering deposition.
After patterning the ITO glass substrate (manufactured by Geomatec) on which the transparent electrode film is formed by photolithography, "Semi-Coclean" EL56 (Furuuchi Chemical Co., Ltd.)
), Ultrasonic cleaning with pure water, and drying. Thereafter, the substrate was washed with UV ozone, attached to a vacuum evaporation machine, and evacuated until the degree of vacuum in the apparatus became 5 × 10 −5 Pa or less. First, copper phthalocyanine was 10 nm in thickness by the resistance heating method.
N, N'-diphenyl-N, N'-dinaphthyl-1,
1'-diphenyl-4,4'-diamine (α-NPD)
Was deposited on a 50 nm substrate to form a hole transport layer. Next, 0.3% by weight of 1,3,5,7,8-pentamethyl-4,4-difluoro-4-bora-3a, 4a-
8-hydroxyquinoline-aluminum complex doped with diaza-s-indacene (PM546) (Alq
3) was deposited to a thickness of 50 nm. Thereafter, the thin film layer was exposed to lithium vapor for doping (0.5 nm in equivalent film thickness).
For the second electrode, aluminum was deposited to a thickness of 150 nm to produce an organic electroluminescent element. Remove this element from the vapor deposition machine,
After being kept for 20 minutes under a reduced pressure atmosphere by a rotary pump, it was transferred to an argon atmosphere having an oxygen concentration of 10 ^-4 % and a dew point of -100 ° C. Sealing was performed under the dry atmosphere.
Sealing was performed using 7059 glass manufactured by Corning Co., Ltd. with a sealing resin having the following composition as an adhesive means.

(A), (b) and (c) were mixed and used as a sealing resin. (A) “Epicoat” 82 manufactured by Yuka Shell Epoxy Co., Ltd.
8 (bisphenol A type epoxy resin) 71 parts by weight (b) 29 parts by weight of isophoronediamine (c) 25 parts by weight of rosin-modified maleic acid resin dispersed with carbon black (including 10 parts by weight of carbon black).

The sealing resin layer was formed so as to surround the light emitting region of the device. The sealing plate was placed facing the substrate with the sealing resin layer interposed therebetween, and bonded together. Thereafter, the sealing resin layer was irradiated with laser light using a semiconductor laser (wavelength 830 nm, beam diameter 5 mm) to cure the resin. The organic electroluminescent device sealed in this way did not undergo thermal degradation and was left in an atmosphere of 80 ° C. and 80% RH after sealing.
No dark spots occurred even after 0 hours.

Example 2 An element was manufactured in the same process as in Example 1 by mixing (a) and (b) below as a sealing resin. (A) Two-part epoxy resin adhesive manufactured by Ciba Specialty Chemicals, Inc. XNR3101 100 parts by weight XNH3101 33 parts by weight (b) SPRIT NIGROSINE SJ (Dye Specialities, INC.)
15 parts by weight.

The sealing resin layer was formed so as to surround the light emitting region of the device. The sealing plate was placed facing the substrate with the sealing resin layer interposed therebetween, and bonded together. After that, the wavelength 1064n
The sealing resin layer was irradiated with a laser beam using a semiconductor-excited YAG laser having a diameter of 5 mm and a beam diameter of 5 mm (1 / e ² ) to cure the resin. The organic electroluminescent device thus sealed was not thermally deteriorated, and was left in an atmosphere of 80 ° C. and 80% RH after sealing, but no dark spot was generated even after 200 hours.

Example 3 An element was produced in the same manner as in Example 1 except that the following (a), (b) and (c) were mixed as a sealing resin. (A) “Epicoat” 82 manufactured by Yuka Shell Epoxy Co., Ltd.
8 (bisphenol A type epoxy resin) 71 parts by weight (b) 29 parts by weight of isophorone diamine (c) 10 parts by weight of "KAYASORB" IR-820B (infrared light absorbing dye, manufactured by Nippon Kayaku Co., Ltd.)

The sealing resin layer was formed so as to surround the light emitting region of the device. The sealing plate was placed facing the substrate with the sealing resin layer interposed therebetween, and bonded together. After that, the wavelength 1064n
The sealing resin layer was irradiated with a laser beam using a semiconductor-excited YAG laser having a diameter of 5 mm and a beam diameter of 5 mm (1 / e ² ) to cure the resin. The organic electroluminescent device thus sealed was not thermally deteriorated, and was left in an atmosphere of 80 ° C. and 80% RH after sealing, but no dark spot was generated even after 200 hours.

Comparative Example 1 An element was prepared and sealed in the same steps as in Example 1 except that (a) and (b) were mixed and used as a sealing resin. (A) “Epicoat” 82 manufactured by Yuka Shell Epoxy Co., Ltd.
8 (bisphenol A type epoxy resin) 71 parts by weight (b) 29 parts by weight of isophoronediamine.

When the laser irradiation was continued until the resin was cured, the temperature of the entire device became high, and the vapor deposition layer of the organic substance was thermally deteriorated and became cloudy. The organic electroluminescent device sealed in this way could not obtain sufficient luminance.

Comparative Example 2 An element was manufactured in the same process as in Example 1 by mixing (a) and (b) below as a sealing resin. (A) “Epicoat” 82 manufactured by Yuka Shell Epoxy Co., Ltd.
8 (bisphenol A type epoxy resin) 71 parts by weight (b) 29 parts by weight of isophoronediamine.

The sealing resin layer was formed so as to surround the light emitting region of the device. The sealing plate was placed facing the substrate with the sealing resin layer interposed therebetween, and bonded together. After curing under the heat curing condition of 80 ° C. for 3 hours and bonding the substrate and the sealing plate, 80 ° C., 80% R
When left in an atmosphere of H, the expansion of the dark spot was observed after 100 hours.

COMPARATIVE EXAMPLE 3 Under the thermosetting conditions of Comparative Example 2, curing was insufficient. Therefore, when the same sealing resin was used and cured by heating at 120 ° C., the resin was cured. Was clouded, and sufficient luminance could not be obtained.

Comparative Example 4 An element was produced and sealed in the same manner as in Example 1 except that frit glass was used as a sealing agent. When the laser irradiation was continued until the frit glass was melted, the temperature of the entire device became high, and the vapor-deposited layer of the organic substance was thermally deteriorated and became cloudy. The organic electroluminescent device sealed in this way could not obtain sufficient luminance.

[0039]

According to the present invention, by including a light-to-heat conversion material in a sealing adhesive for bonding a substrate and a sealing plate, the adhesive can be efficiently heated by laser irradiation or the like. Thus, even when a thermosetting adhesive is used, the sealing can be performed without thermally deteriorating the light emitting layer portion of the organic electroluminescent device.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an organic electroluminescent device manufactured by the present invention.

FIG. 2 is a sectional view showing another example of the organic electroluminescent device manufactured by the present invention.

FIG. 3 is a sectional view showing another example of the organic electroluminescent device manufactured by the present invention.

FIG. 4 is a sectional view showing another example of the organic electroluminescent device manufactured by the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 first electrode 3 drive source 5 hole transport layer 6 light emitting layer 8 second electrode 9 protective layer 21 sealing plate 22 sealing adhesive 23 sealed internal space 24 recess 25 leg

Claims (3)

[Claims] A first electrode formed on the substrate, a thin film layer formed on the first electrode, the light emitting layer including at least an organic compound, and a second electrode formed on the thin film layer; An organic electroluminescent device including a sealing plate bonded to a substrate with an agent, wherein the adhesive contains a photothermal conversion material. 2. The organic electroluminescent device according to claim 1, wherein the adhesive is a resin whose curing is accelerated by heat. 3. The organic electroluminescent device according to claim 1, further comprising a step of selectively heating and curing the adhesive by using a laser beam to bond the substrate and the sealing plate. Production method.