JPH10172768A - Light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably emit the light so that a dark spot is not recognized by visual observation by eliminating or reducing a pinhole of a light emitting element, by restricting the size of defects and the average area and its number of the defects in an anode or a cathode in a light emitting element. SOLUTION: In a light emitting element, an anode, an electron hole transport layer, a diazaindacene doping layer, an electron transport layer, a cathode or the like are laminated in this order. In this element, a part containing a factor in becoming a pinhole when an organic substance is evaporated or while the light is emitted, is called a defect. It is desirable that this defect does not exist, but practically, the size of a degree unrecognizable by visual observation is an allowable range. To put it concretely, the maximum allowable area of a defect part is restrained to 0.3mm<2> or less. The average area when defects exist in a plurality is set not more than 10000m<2> /a piece. When the size of the defects is small, since it happens that the defects are closed up at evaporation time, when they are made small as much as possible, it is more effective in restraining the pinhole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an element capable of converting electric energy into light, and is applicable to fields such as display elements, flat panel displays, backlights, lighting, interiors, signs, signboards, and electrophotographic machines. Planar light emitter.

[0002]

2. Description of the Related Art An organic laminated thin-film light-emitting device that emits light when electrons injected from a cathode and holes injected from an anode recombine in an organic phosphor sandwiched between both electrodes is thin and has a low driving voltage. It is characterized by high brightness light emission and multicolor light emission. This organic laminated thin film element emits light with high luminance, as described by Kodak C.I. W. Tang et al. (A
ppl. Phys. Lett. 51 (12) 21, p.
913, 1987).

[0003] A typical structure of an organic laminated thin film light emitting device presented by Kodak Company is a diamine compound having a hole transporting property on an ITO glass substrate, tris (8-quinolinolato) aluminum as a light emitting layer, and Mg as a cathode: Ag is sequentially provided, and a driving voltage of about 10 V
Green light emission of cd / m ² was possible. The feature of the present invention resides in that a diamine compound as a hole transport layer is provided between tris (8-quinolinolato) aluminum as an illuminant and ITO as an anode, thereby dramatically improving luminous brightness. . The present organic laminated thin-film light-emitting device has a different configuration, such as a device provided with an electron transport layer in addition to the above-described device components, but basically follows the configuration of Kodak Company.

As a host material for the light emitting layer, Japanese Patent Application Laid-Open
Metal oxine derivatives such as tris (8-quinolinolato) aluminum described in JP-A-264692, 1,4-diphenylbutadiene, 1,1,4,4-
Tetraphenylbutadiene (JP-A-59-194393)
), Styryl compounds (JP-A-2-247278, JP-B-7-98787), benzoxazole derivatives, benzothiazole derivatives, and transstilbenes. On the other hand, as a dopant as a guest material, coumarin derivatives known to be useful as laser dyes such as 7-dimethylamino-4-methylcoumarin and the like (J. Appl. Phys. 65 (9) 3
610 (1989), JP-A-63-264692, JP-A-6-240243), dicyanomethylenepyran dye, dicyanomethylenethiopyran dye, cyanine dye,
Xanthene dyes, pyrylium dyes, carbostyril dyes, perylene dyes (JP-A-63-264892), perylene, tetracene, pentacene (JP-A-2-
No. 261889), 4- (dicyanomethylene) -2
-Methyl-6- (p-dimethylaminostyryl) -4H
Pyran, 3- (2'-benzimidazoyl) -7-N,
N-diethylaminocoumarin (JP-A-3-26780), quinacridone compound, quinazoline compound (JP-A-5-70773, JP-A-3-255190), pyrrolopyridine, furopyridine (JP-A-5-22)
No. 2360), 1,2,5-thiazizolopyrene derivatives (JP-A-5-222361), perinone derivatives (JP-A-5-279662, Jpn. J. App.
l. Phys. , 27, L713 (1988)), a pyrrolopyrrole compound (JP-A-5-320633),
Squarylium compound (JP-A-6-93257)
Etc. are known.

[0005] However, the organic laminated thin film element manufactured by the conventional technique has a problem that a non-light-emitting portion called a dark spot grows during storage, so that display characteristics are significantly impaired. Various causes have been pointed out as a cause of the generation of dark spots, such as the influence of moisture and oxygen entering the inside of the device, crystallization of organic substances, and an interface peeling phenomenon in each layer. Above all, moisture in the atmosphere is an important point in suppressing dark spots because it tends to greatly affect active parts in the device. To minimize this effect, a number of negative electrode fabrication methods, a cathode protection layer (cap layer),
Then, a method of sealing the element has been devised. For example, a cap layer provided on the cathode (JP-A-4-233194), an indium cathode having an average particle diameter of less than 1 μm (JP-A-5-101892), and a metal which can be oxidized in the presence of ambient moisture. And other protective layers (Japanese Patent Application Laid-Open No. H5-159881). These sealing methods are basically based on the premise that a dark spot is generated when the element is placed in a normal atmosphere, and have been devised as means for suppressing this. It is said that the effect of moisture and oxygen in the atmosphere to generate dark spots is affected by pinholes formed in the device. In other words, moisture and oxygen enter from the pinhole portion to make the element not shine.
In other words, eliminating pinholes makes it possible to produce an element without dark spots. However, it has been difficult to eliminate pinholes using any conventional method.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate a pinhole of a light emitting element, or to eliminate a dark spot even if it is very small without practical use. Accordingly, an object of the present invention is to provide a light-emitting element that can emit light stably.

[0007]

According to the present invention, there is provided an element which emits light by electric energy, wherein a substance which controls light emission is present between an anode and a cathode. There is no defect having an area of 3 mm ² or more, and the average area of defects of the anode or the cathode is 100%.
The present invention relates to a light-emitting element having a size of not more than 00 μm ² / piece, whereby the occurrence of a dark spot can be significantly suppressed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the anode is made of a conductive metal oxide such as tin oxide, indium oxide, indium tin oxide (ITO), or gold, silver, chromium or osmium, if it is transparent to extract light. Such as metals, laminates of these metals with ITO, inorganic conductive substances such as copper iodide and copper sulfide, conductive polymers such as polythiophene, polypyrrole, and polyaniline, and laminates of these conductive polymers and ITO Although not particularly limited, it is particularly desirable to use ITO glass or Nesa glass from the viewpoint of transmittance of visible light. It is desirable to transmit at least 50% or more.
% Is more desirable. The resistance of the transparent electrode is not particularly limited as long as a current sufficient for light emission of the element can be supplied, but is preferably low from the viewpoint of power consumption of the element. For example, an ITO substrate having a resistance of 300 Ω / □ or less functions as an element electrode. However, it is particularly preferable to use a substrate having a resistance of 20 Ω / □ or less because a low-resistance substrate can be supplied at present. The thickness of ITO can be arbitrarily selected according to the resistance value.
Often used between ~ 3000 Angstroms. In addition, the substrate of ITO is made of soda lime glass, non-alkali glass, transparent resin, or the like, and the thickness is sufficient if it has a sufficient thickness to maintain mechanical strength. It is enough. As for the material of the glass, non-alkali glass is preferable because it is preferable that the amount of ions eluted from the glass is small, but soda lime glass can also be used. In this case, since soda lime glass provided with a barrier coat such as SiO 2 is commercially available, it is more preferable to use this. The method of forming the ITO film is not particularly limited, such as an electron beam method, a sputtering method, and a chemical reaction method. In addition, ITO
It is already known that the drive voltage of the element can be reduced by UV-ozone treatment, but this fact can be applied to the present invention.

Since the cathode must efficiently supply electrons to a substance which controls light emission or a substance adjacent to the substance which controls light emission (for example, an electron transporting layer), the adhesion between the electrode and the adjacent substance and the ionization potential. Adjustments are required. In addition, it is particularly desirable to use a material that is relatively stable in the air in order to maintain stable performance for long-term use. However, it is possible to use a protective film, etc. It is not something to be done. Specifically, indium, gold, silver, aluminum,
It is possible to use metals such as lead and magnesium, rare earth simple substances, alkali metals, or alloys thereof, but considering element characteristics, magnesium, lithium,
It is desirable to use a low work function metal such as potassium or sodium. However, since these metals are very active and unstable, alloys with silver or aluminum can be used. An electrode is manufactured by a resistance heating method, an electron beam method, a sputtering method, a coating method, or the like. A metal can be deposited alone or two or more components can be deposited simultaneously. Particularly, for forming an alloy, an alloy electrode can be easily formed by depositing a plurality of metals at the same time, or an alloy may be deposited. Further, as a more preferable example, a method in which a doping treatment is applied to an organic layer and then a negative electrode is produced. This has the advantage that co-evaporation is not required and that a stable single metal can be used for the electrode, but it need not be. The dopan doped in the organic layer is preferably an alkali metal such as lithium, sodium or potassium, an alkaline earth metal such as magnesium or calcium, or an organic donor molecule such as ammonia, tetrathiofulvalene or tetraselenofulvalene. The doping amount is very small and shows a sufficient effect, and is usually 1 nm or less as measured by a film thickness sensor. The doping process is
It is preferably performed in a vacuum, but can be performed in the air or in an inert atmosphere. After performing the doping process, the metal negative electrode is made into a predetermined shape, but metals such as indium, gold, silver, copper, iron, aluminum, chromium, tungsten, lead, and alloys containing these and carbon are mainly produced by vacuum evaporation. Can be used. Among them, aluminum, indium, and silver are particularly preferably used metals from the viewpoint of resistance value, ease of pattern formation, and the like.

The substance which controls light emission includes: 1) a hole transport layer / a light emitting layer, 2) a hole transport layer / a light emitting layer / an electron transport layer, 3) a light emitting layer / an electron transport layer, and 4) a combination of the above. Any of the forms in which the combined substances are mixed together may be used. That is, as the element configuration, it is only necessary to provide a single layer containing a light emitting material, a hole transporting material and / or an electron transporting material as in 4) in addition to the above-described multilayered structures 1) to 3).

In the hole transport layer, a carbazolyl derivative, a biscarbazolyl derivative, a multimer of triphenylamine,
N, N'-bis (3-methylphenyl) -N, N'-diphenyl-4,4'-diamino-1,1'-diphenyl (TPD), N, N'-bis (1-naphthyl) -N , N
'-Diphenyl-4,4'-diamino-1,1'-diphenyl (α-NPD), m-MTDATA, poly (N-
Known hole transport materials such as vinyl carbazole), polysilane, polygermane, and metal or metal-free phthalocyanine can be laminated or mixed. Among them, triphenylamine derivatives and biscarbazolyl derivatives are particularly preferable examples in view of the performance of the device.
One example is shown below, but it is not particularly limited to these.

[0012]

Embedded image The formation of the hole transport layer is mainly performed by a vacuum evaporation method, but the coating from a solution or the above-described monomer hole transport material is made of polyvinyl chloride, polycarbonate, polystyrene,
Poly (N-vinyl carbazole), polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, vinyl acetate, ABS resin ,
Solvent-soluble resin such as polyurethane resin, phenol resin, xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, silicone resin, etc. are dissolved or dispersed in a solvent and coated. It is also possible. It is desirable to reduce the thickness of the hole transport layer to the `` limit film thickness '' at which the leakage current of the element increases in consideration of the driving voltage,
In consideration of the durability of the element, it is preferable that the thickness be larger than the “limit film thickness”. The preferred thickness of the hole transport layer is not limited because it varies depending on the surface state of the ITO substrate, the constituent material of the hole transport layer, and the like, but is preferably about 20 to 1000 nm, and more preferably 50 to 300 nm.

The light-emitting layer may be made to emit light with a single light-emitting material, or may be used by mixing two or more kinds of light-emitting materials. Either method may be used. Among the methods for mixing light emitters, the doping method is a method in which a dopant serving as a guest is mixed with a phosphor substance serving as a host to emit light from the dopant. As the host material of the light emitting layer material, anthracene and pyrene, which have long been known as light emitters,
Metal complexes of quinolinol derivatives represented by aluminum 8-hydroxyquinoline, and bisstyrylanthracene derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, oxadiazole derivatives, distyrylbenzene derivatives, pyrrolopyridine derivatives, perinone derivatives, and cyclopentadiene derivatives , An oxadiazole derivative, a thiadiazolopyridine derivative, and a polymer system such as a polyphenylenevinylene derivative, a polyparaphenylene derivative, and a polythiophene derivative.

As the dopant, rubrene, quinacridone derivatives, phenoxazone 660, DCM1, condensed hydrocarbons such as perinone and perylene, coumarin derivatives,
Diazaindacene derivatives, styryl derivatives, bisstyryl derivatives and the like can be used. The method for forming the light-emitting layer is not particularly limited, such as resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination, and coating. However, resistance heating evaporation and electron beam evaporation are usually preferable in terms of characteristics. The thickness of the light-emitting layer cannot be limited because it depends on the resistance of the substance that controls light emission.
〜1000 nm.

As the electron transport material, it is necessary to efficiently transport electrons from the cathode between the electrodes to which an electric field is applied, and it is desirable to have a high electron injection efficiency and to efficiently transport the injected electrons. . For this purpose, it is required that the material has a high electron affinity, a high electron mobility, a high stability, and a small amount of impurities serving as traps during production and use. An oxine-based complex such as tris (8-quinolinolato) aluminum, which is known as a luminescent substance having an electron transporting ability as a substance satisfying such conditions, tris (benzquinolinolato)
Aluminum, oxadiazole derivative, triazine derivative, perylene derivative, perinone derivative, naphthalene,
There are coumarin, oxadiazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, pyridine derivatives, phenanthroline derivatives, and the like, but are not particularly limited. The electron transporting substance can be in any of a single form, a laminated form, and a mixed form, and can have an optimal form in combination with a light emitting layer and a cathode.

In the present invention, one of the most suitable embodiments is an element laminated in the order of anode / hole transport layer / diazaindacene doping layer / electron transport layer / cathode. However, the present invention is not limited to this.

The ITO substrate is manufactured by several methods such as electron beam evaporation, sputtering, and coating.
Defects in which ITO does not exist no matter which method is used
Due to foreign matters left on the surface of the glass substrate before film formation, scratches, protrusions, holes, and the like on the glass substrate itself, ITO is not partially formed or there is a thinned portion. Such a portion becomes a pinhole. Further, even after the ITO film is formed, a pinhole is formed when dust, foreign matter (organic or inorganic), and floating organic components (such as a hydrocarbon compound and an amine compound) adhere to the surface in the same manner. In the present invention, this is also defined as a defect. That is, in the present invention, a portion including a factor that becomes a pinhole when an organic substance is deposited or during the issuance of an organic substance is referred to as a defect. The disadvantages of the present invention are most preferably absent, but in practice it is extremely difficult to eliminate them all. Therefore, practically, a size that cannot be visually recognized can be said to be an allowable range. Specifically, the maximum allowable area of the defect is 0.3 mm ² (diameter of 600 μm for a perfect circle, 550 μm for a side of a square). Since the size of one pixel is reduced to a size of 300 μm, at least the maximum area is 0.03 mm ² (diameter of 200 μm for a perfect circle, 170 μm for a square)
m) should be kept below. When there are a plurality of defects (usually a plurality of defects), the smaller the average area is, the better it is, but at least 10,000 μm ²
/ (The diameter is 110 μm for a perfect circle and 100 μm on a side for a square). In order to further obtain a high-quality image, more preferably 200
Desirably, it is 0 μm ² / piece (diameter: 50 μm for a perfect circle, 45 μm for a square). When the size of the defect is small, the defect may be closed during the vapor deposition. Therefore, it can be said that the smaller the defect is, the more effective the pinhole suppression is. The disadvantage is not only the size, but also the existing density. No matter how small the defect, the higher the number, the better the quality of the display. The density of this defect depends on the quality of the display (both display and planar illuminant)
In consideration of the above, those having an area of 0.1 μm ² or more should be suppressed to at most 3000 pieces / cm ^{2, and} more preferably the number is 1000 pieces / cm ² or less.
If the above preferable conditions can be satisfied, not only the occurrence and growth of dark spots are remarkably suppressed, but also the leakage current in the device can be drastically reduced. Becomes possible.

There are several ways to determine the presence and size of a defect. Foreign substances adhering to the surface and abnormal portions of the glass substrate can be observed with a stereoscopic microscope or a differential interference microscope, and the suspended organic components can be analyzed by time-of-flight secondary ion mass spectrometry (TOF-
Observation is possible by SIMS) or X-ray photoelectron spectroscopy (ESCA). Defects of ITO, scratches, projections, holes, etc. on the glass substrate can be measured by two-dimensional measurement of surface roughness, atomic force microscope (AFM), cross-sectional observation using a focused ion beam, etc., but a relatively simple method Alternatively, a method in which a metal or the like is electrodeposited on the ITO surface and observed with an optical microscope or the like can be used.

The concept for obtaining an ITO electrode having few defects as shown in the present invention is as follows. Basically, a substrate for forming an ITO film is free from foreign matter, scratches, protrusions, holes, or the like. Need to be at the submicron level. For this purpose, it is necessary to sufficiently clean the film using a glass substrate having a high smoothness before the film formation under more strictly controlled conditions than usual. Especially when the glass is polished, careful cleaning is desirable since abrasives and foreign substances are likely to remain. When soda-lime glass is used, a silica barrier layer may be provided to suppress alkali elution. The methods include coating, CVD, R
There are F sputtering method, ion plating method, etc.
There is no particular limitation as long as a flat film free of undulations and foreign substances can be obtained. Empirically, coating methods are more difficult to achieve flatness than other methods. In addition, the method of forming ITO also affects the formation of defects. The method includes a vacuum deposition method, a sputtering method, an ion plating method, a coating method, and the like. However, there is no particular limitation as long as the portion does not have an ITO film or the film quality is easily peeled. The surface shape of ITO varies greatly depending on the film forming method and film forming conditions. In order to obtain an element having a small number of pinholes, it is necessary that there is no large protrusion. Therefore, an appropriate film formation method and a film formation method should be used. Empirically, sputtering or ion plating can produce a flatter film than vacuum deposition. However, when the oxygen partial pressure during sputtering is low, the particle size is relatively large. However, as the oxygen partial pressure increases, the particle size decreases, and when the discharge voltage is low, large domains are observed. Annealing also affects the change in film quality, and the treatment can be performed in a vacuum or in the air at a temperature of 100 to 500 ° C. On the other hand, the element characteristics greatly depend on the shape of the ITO surface, and appropriate roughness is required.
It is necessary to determine a film forming method and a film forming condition so as to satisfy these requirements as much as possible.

Even if an element is manufactured based on the method of the present invention, it is extremely difficult to eliminate all pinholes. In the case of a display in the form of a dot matrix, a non-light-emitting portion is formed from the end of a pixel. Since the phenomenon of spreading over time is inevitable, it is necessary to seal the device by some method after the device is manufactured. As a sealing method, a conventionally known method can be used as long as the outside air can be shut off. For example, after the device is manufactured, a protective film is preferably formed by a dry process such as vacuum deposition, plasma polymerization, or CVD. Materials include inorganic substances such as silicon oxide, titanium oxide, magnesium oxide, and magnesium fluoride, polyethylene, polypropylene, polyvinylidene fluoride (PVDF), and PTF.
Organic substances such as E, polyvinylidene chloride, and hydrocarbon are preferably used. This protective film may be used alone, or may be laminated with some of these substances or a metal such as aluminum, silver, gold, or indium. If the function of the protective film alone is not sufficient depending on the application, a sealing layer made of a material having a higher shielding property is provided thereon to perform sealing. Materials with high shielding properties include metals such as glass, stainless steel, aluminum, and iron, and polymer films or sheets such as polyester, nylon, vinyl chloride, polyethylene, and polypropylene, or materials with high shielding properties such as aluminum deposited on these. What was done is used. In the case of sealing with these materials, the sealing is usually performed by closing the opening with an adhesive, but a method such as thermocompression bonding is also possible. Adhesives include epoxy, urethane, cyanoacrylate, silicone, acrylic, etc., which have high adhesion to the substrate and the material of the encapsulation layer, low gas and water vapor permeability, and vary depending on device usage conditions. Of course, it is preferable to have heat resistance and weather resistance that are not so high, but to cure as quickly as possible and to have low outgassing during and after curing. As a curing method, heat curing and light curing are mainly preferred examples. The curing temperature is not particularly limited, but a material which can be cured at a low temperature as much as possible in consideration of thermal deterioration of the element is preferable. In the case of photocuring, there are cases where light in the ultraviolet region is used and light in the visible region is used. Either wavelength may be used, but if the organic material constituting the device is sensitive to ultraviolet light, it is desirable to use visible light, but if ultraviolet light is not irradiated to the organic material by an appropriate method,
Ultraviolet light can also be used. The viscosity of these adhesives is preferably from 10 to 100,000 cps from the viewpoint of easy handling, and when the adhesive is applied to the outer peripheral portion of the display, the viscosity is more preferably from 500 to 30,000 cps from the viewpoint of shape stability.

The light-emitting element according to the present invention can be applied to devices requiring light emission, such as a planar light-emitting element, a display of a segment system, and a display using a dot matrix. Examples include a numeric display, a segment display suitable for analog bar graph display, a symbol display, a fixed pattern display suitable for pattern display, a character display, a graphic display, a matrix display suitable for video display, and the like. As a driving method, each segment electrode to be displayed is individually
And static driving for simultaneous driving, multiplex driving (line-sequential driving) applied in the case of using a relatively large number of segment electrodes such as a multi-digit number display or matrix electrode configuration, and scanning and signal electrodes. A switch element and a capacitor element as needed are added and integrated for each pixel at a matrix intersection, and active matrix driving is performed to improve display characteristics such as contrast and response. A particularly preferable driving method is not limited since an appropriate driving method differs depending on the application. For example, in the case of a small display using matrix driving, a line sequential driving method having a simple structure can be cited as a preferable example. In this case, the highest luminance is particularly important, and the required luminance increases as the number of scanning lines increases. In the case of active driving, high luminance is not required as in the case of line-sequential driving, but it is also desirable that the maximum luminance of the element be 1000 cd / m ² or more from the viewpoint of life.

[0022]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 An alkali-free glass (7059, manufactured by Corning Incorporated) having a size of 10 × 10 cm and a thickness of 1.1 mm was polished and washed, and then an ITO film having a thickness of 135 nm was formed by a sputtering method. At this time, the resistance was about 13 Ω / □, and the light transmittance at 550 nm was 85%. The maximum defect area of this ITO substrate is 0.02mm
^{2. The} average area was 1960 μm ² / piece, and the number of defects was 672 pieces / cm ² . This ITO was etched into a predetermined shape and washed with acetone, Semico Clean 56, pure water, isopropyl alcohol, and methanol.
The ITO substrate was washed with UV-ozone (manufactured by Sen Engineering Co., Ltd.), and then attached to a vacuum evaporation machine and evacuated. When the degree of vacuum reaches 5 × 10 ⁻⁴ Pa, copper phthalocyanine is evaporated to a thickness of 20 nm, bis (m-methylphenylcarbazole) is evaporated to a thickness of 100 nm, and tris (8-quinolinolato) aluminum (III) complex is evaporated to a thickness of 100 nm. Was replaced. Next, the laminated film was exposed to lithium vapor for doping (amount of 1 nm as indicated by a film thickness meter), and then aluminum was deposited to a thickness of 200 nm to produce a 5 × 5 mm square element. Put this device in air (relative humidity 63
%) And a constant current drive of 20 mA / cm ² for 24 hours, the number of dark spots that can be visually discriminated was 17/25 mm ² , and the average diameter was 60 μm.

Example 2 One side of a soda lime glass substrate was polished and washed, and then CV
A 70 nm SiO2 film was formed on the polished surface by Method D. After that, the 180 nm ITO
A film was formed. At this time, the resistance value of the ITO film is about 15Ω /
It was □. The maximum defect area of this ITO substrate is 0.02
The area was 4 mm ² , the average area was 2240 μm ² / piece, and the number of defects was 932 pieces / cm ² . Otherwise, Example 1
When the device was prepared and evaluated by the same method as in Example 1, the number of dark spots that could be visually discriminated was 23/25 mm ² , and the average diameter was 80 μm.

Example 3 One side of a soda lime glass substrate was polished and cleaned, and then RF
After forming a 20 nm SiO ₂ film on the polished surface by the sputtering method, the in-line 128 nm is formed by the sputtering method.
Was formed. At this time, the resistance value of the ITO film was about 12.5 Ω / □. The maximum defect area of the present ITO substrate was 0.022 mm ² , the average area was 2010 μm ² / piece, and the number of defects was 723 pieces / cm ² . Otherwise, when an element was prepared and evaluated in the same manner as in Example 1, the number of dark spots that could be visually identified was 20/2.
5 mm ² and its average diameter was 72 μm. Comparative Example 1 One surface of a soda lime glass substrate was polished and washed, and then a SiO2 film was formed by a dipping method. Thereafter, a 150 nm ITO film was formed by an electron beam method. At this time, the resistance value of the ITO film was about 15 Ω / □. Book I
The area of the maximum defect of the TO substrate is 0.4 mm ² , the average area is 12400 μm ² / piece, and the number of defects is 3560 pieces / piece.
cm ² . Otherwise, when the device was manufactured and evaluated by the same method as in Example 1, the number of dark spots that can be visually discriminated was 245/25 mm ² , and the average diameter was 235 μm.

[0026]

According to the present invention, it is possible to provide an organic laminated thin film element in which the generation of non-light-emitting portions (dark spots) formed on the light-emitting surface is significantly reduced.

Claims (13)

[Claims] An element which emits light by means of electric energy, wherein a substance responsible for light emission is present between an anode and a cathode, wherein the anode or the cathode has no defect of an area of 0.3 mm ² or more. The average area of defects of the anode or cathode is 100
A light emitting element having a size of not more than 00 μm ² / piece. 2. An element which emits light by electric energy, in which a substance responsible for light emission exists between an anode and a cathode, wherein the anode has no defect having an area of 0.3 mm ² or more, and A light-emitting element, wherein the average area of the defects is 10,000 μm ² / piece or less. 3. The light emitting device according to claim 1, wherein there is no defect having an area of 0.03 mm ² or more, and the average area of the defect is 2000 μm ² / piece or less. 4. The light emitting device according to claim 1, wherein the number of defects is 3000 / cm ² or less. 5. The light-emitting device according to claim 4, wherein the number of defects is 1000 / cm ² or less. 6. The light emitting device according to claim 1, wherein the anode is a transparent electrode capable of transmitting 60% or more of visible light. 7. The light emitting device according to claim 1, wherein the anode is made of indium tin oxide. 8. The substance which controls light emission is at least hole-injected.
The light emitting device according to any one of claims 1 to 7, comprising a transport layer and a light emitting layer. 9. The light emitting device according to claim 8, wherein the hole injecting / transporting layer is made of a compound having a triphenyl skeleton. 10. The light emitting device according to claim 8, wherein the hole injection / transport layer is made of a compound having a carbazolyl skeleton. 11. An anode and a cathode each constitute a strip row electrode or the other strip column electrode, and have a matrix electrode capable of displaying an arbitrary pattern by selectively applying a voltage to an arbitrary intersection. The light emitting device according to claim 1. 12. The light emitting device according to claim 1, wherein a switch element is provided for each pixel at a matrix intersection of the scanning electrode and the signal electrode. 13. The light emitting device according to claim 1, wherein the light emitting device is a planar light emitting body.