JPH0794278A - Organic thin film light emitting element - Google Patents
Organic thin film light emitting elementInfo
- Publication number
- JPH0794278A JPH0794278A JP5233973A JP23397393A JPH0794278A JP H0794278 A JPH0794278 A JP H0794278A JP 5233973 A JP5233973 A JP 5233973A JP 23397393 A JP23397393 A JP 23397393A JP H0794278 A JPH0794278 A JP H0794278A
- Authority
- JP
- Japan
- Prior art keywords
- injection layer
- light emitting
- film thickness
- charge injection
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000010409 thin film Substances 0.000 title claims abstract description 33
- 238000002347 injection Methods 0.000 claims abstract description 59
- 239000007924 injection Substances 0.000 claims abstract description 59
- 239000010408 film Substances 0.000 claims abstract description 41
- 239000000126 substance Substances 0.000 claims abstract description 30
- 239000000758 substrate Substances 0.000 claims description 8
- 239000010410 layer Substances 0.000 description 73
- 238000000034 method Methods 0.000 description 15
- 238000010438 heat treatment Methods 0.000 description 11
- 238000005566 electron beam evaporation Methods 0.000 description 7
- 230000008020 evaporation Effects 0.000 description 7
- 238000001704 evaporation Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 238000007740 vapor deposition Methods 0.000 description 5
- 239000000956 alloy Substances 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 238000005266 casting Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 229910017911 MgIn Inorganic materials 0.000 description 3
- 238000004528 spin coating Methods 0.000 description 3
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000001451 molecular beam epitaxy Methods 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 1
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 229920001940 conductive polymer Polymers 0.000 description 1
- 238000005401 electroluminescence Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000012044 organic layer Substances 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 229920000128 polypyrrole Polymers 0.000 description 1
- 229920000123 polythiophene Polymers 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- TVIVIEFSHFOWTE-UHFFFAOYSA-K tri(quinolin-8-yloxy)alumane Chemical compound [Al+3].C1=CN=C2C([O-])=CC=CC2=C1.C1=CN=C2C([O-])=CC=CC2=C1.C1=CN=C2C([O-])=CC=CC2=C1 TVIVIEFSHFOWTE-UHFFFAOYSA-K 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K2102/00—Constructional details relating to the organic devices covered by this subclass
- H10K2102/301—Details of OLEDs
- H10K2102/351—Thickness
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/30—Devices specially adapted for multicolour light emission
- H10K59/35—Devices specially adapted for multicolour light emission comprising red-green-blue [RGB] subpixels
Landscapes
- Electroluminescent Light Sources (AREA)
- Luminescent Compositions (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は有機薄膜発光素子の積
層構造に係り、特に制御された膜厚を有する発光層と電
荷注入層に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated structure of an organic thin film light emitting device, and more particularly to a light emitting layer having a controlled film thickness and a charge injection layer.
【０００２】[0002]
【従来の技術】従来のブラウン管に代わるフラットディ
スプレイの需要の急増に伴い、各種表示素子の開発及び
実用化が精力的に進められている。エレクトロルミネセ
ンス素子（電場発光素子）もこうしたニ−ズに即するも
のであり、特に全固体の自発発光素子として、他のディ
スプレイにはない高解像度及び高視認性により注目を集
めている。現在、実用化されているものは、発光層にＺ
ｎＳ／Ｍｎ系を用いた無機材料からなる電場発光素子で
ある。しかるに、この種の無機電場発光素子は発光に必
要な駆動電圧が１００Ｖ以上と高いため駆動方法が複雑
となり製造コストが高いといった問題点がある。また、
青色発光の効率が低いため、フルカラ−化が困難であ
る。これに対して、有機材料を用いた薄膜薄膜電場発光
素子（以下有機薄膜発光素子という）は、発光に必要な
駆動電圧が大幅に低減でき、かつ各種発光材料の適用に
よりフルカラ−化の可能性を充分に持つことから、近年
研究が活発化している。2. Description of the Related Art With the rapid increase in demand for flat displays replacing conventional cathode ray tubes, various display elements have been vigorously developed and put into practical use. Electroluminescence devices (electroluminescent devices) are also suitable for such needs, and as an all-solid-state spontaneous light-emitting device, they are attracting attention because of their high resolution and high visibility not found in other displays. Currently, the one that has been put to practical use is Z in the light emitting layer.
It is an electroluminescent element made of an inorganic material using an nS / Mn system. However, this type of inorganic electroluminescent device has a problem that the driving method is complicated and the manufacturing cost is high because the driving voltage required for light emission is as high as 100 V or more. Also,
Since the efficiency of blue light emission is low, full colorization is difficult. On the other hand, a thin film thin film electroluminescent device using an organic material (hereinafter referred to as an organic thin film light emitting device) can drastically reduce the driving voltage required for light emission, and can be fully colored by applying various light emitting materials. Since it has enough, the research has been activated in recent years.
【０００３】特に、電極／正孔注入層／発光層／電極か
らなる積層型において、発光剤にトリス（８−ヒドロキ
シキノリン）アルミニウムを、正孔注入剤に１，１−ビ
ス（４−Ｎ，Ｎ−ジトリルアミノフェニル）シクロヘキ
サンを用いることにより、１０Ｖ以下の印加電圧で１０
００ｃｄ／ｍ2 以上の輝度が得られたという報告がなさ
れて以来開発に拍車がかけられた（Appl.Phys.Lett. 5
1,913,(1987))。In particular, in the laminated type composed of electrode / hole injecting layer / light emitting layer / electrode, tris (8-hydroxyquinoline) aluminum is used as the light emitting agent and 1,1-bis (4-N, By using N-ditolylaminophenyl) cyclohexane, an applied voltage of 10 V or less
Since it was reported that a brightness of more than 00 cd / m 2 was obtained, the development was spurred (Appl.Phys.Lett. 5
1 , 913, (1987)).
【０００４】現在フルカラー化を目指して三原色各色の
発光物質の開発が進められている。At present, the development of light-emitting substances for each of the three primary colors is underway with the aim of achieving full-color.
【０００５】[0005]
【発明が解決しようとする課題】以上のように有機薄膜
発光素子は次世代のフルカラーフラットディスプレー素
子としての可能性を強く示唆しているが実際の素子製作
には解決しなければならない多くの課題を抱えている。
その一つは同一基板上の赤青緑の各画素の駆動電圧特性
即ち電圧−輝度特性にばらつきがあることである。As described above, the organic thin film light emitting device strongly suggests the possibility as a next-generation full color flat display device, but there are many problems to be solved in actual device fabrication. Have a
One of them is that the driving voltage characteristics, that is, the voltage-luminance characteristics of the red, blue, and green pixels on the same substrate vary.
【０００６】各画素における電圧−電流密度特性ならび
に電流密度−輝度特性がそれぞれ異なるため同一の素子
構造では所望の輝度を得るための駆動電圧に差異を生じ
る。このために駆動電圧回路が複雑になるという問題が
ある。本発明は上述の点に鑑みてなされその目的は、各
画素の素子構造を変化させることにより、各画素に対し
て所望の輝度を実現しながら全画素を一定の駆動電圧で
駆動することが可能な有機薄膜発光素子を提供すること
にある。Since the voltage-current density characteristic and the current density-luminance characteristic of each pixel are different from each other, the driving voltage for obtaining the desired luminance differs in the same device structure. Therefore, there is a problem that the driving voltage circuit becomes complicated. The present invention has been made in view of the above points, and it is an object of the present invention to change the element structure of each pixel so that all pixels can be driven with a constant drive voltage while realizing a desired brightness for each pixel. Another object is to provide a simple organic thin film light emitting device.
【０００７】[0007]
【課題を解決するための手段】本発明者等は駆動電圧の
一定化を図るために鋭意研究を重ねた結果、発光層には
所望の発光輝度を最小の電流密度で達成することを可能
にする最適膜厚が存在すること、および電荷注入層の膜
厚により有機薄膜発光素子の輝度／電流密度特性に変化
がないことを見いだしこの知見に基づいて本発明をなす
に至った。Means for Solving the Problems As a result of intensive studies made by the present inventors for the purpose of stabilizing the driving voltage, it has become possible to achieve desired light emission brightness in the light emitting layer with a minimum current density. Based on this finding, it was found that the optimum film thickness exists and that the film thickness of the charge injection layer does not change the brightness / current density characteristics of the organic thin film light emitting device.
【０００８】上述の目的はこの発明によれば有機薄膜を
用いる電場発光素子であって、画素のアレーからなり、
各画素は（１）絶縁性支持体と、（２）正極と、（３）
発光層と、（４）電荷注入層と、（５）負極を包含し、
絶縁性支持体は素子の支持体であり、発光層は所定の波
長の発光を行う発光物質を含んで所望の発光層輝度を最
小の電流密度で実現する膜厚を有し、電荷注入層は正孔
注入層と電子注入層のうちの少なくとも一つからなり、
電荷注入層は膜厚により電荷注入層に印加される電圧を
調節し、正極と負極は画素の駆動電圧が印加されるもの
であるとすることにより達成される。The above-mentioned object is an electroluminescent device using an organic thin film according to the present invention, which comprises an array of pixels,
Each pixel has (1) an insulating support, (2) a positive electrode, and (3)
Including a light emitting layer, (4) charge injection layer, and (5) negative electrode,
The insulative support is a support for the device, the light-emitting layer contains a light-emitting substance that emits light of a predetermined wavelength, has a film thickness that achieves a desired light-emitting layer brightness with a minimum current density, and the charge injection layer is At least one of a hole injection layer and an electron injection layer,
The charge injection layer is achieved by adjusting the voltage applied to the charge injection layer according to the film thickness, and the positive electrode and the negative electrode are applied with the pixel drive voltage.
【０００９】[0009]
【作用】図４は有機薄膜発光素子につき発光物質をパラ
メータとしたときの輝度／電流密度の発光層膜厚依存性
を示す線図である。所望の輝度を最小の電流密度で達成
する最適発光層膜厚が存在することがわかる。図５は有
機薄膜発光素子につき発光物質をパラメータとしたとき
の輝度／電流密度の電荷注入層膜厚依存性を示す線図で
ある。電荷注入層の膜厚の如何に係わらず有機薄膜発光
素子の輝度／電流密度は変わらないことがわかる。FIG. 4 is a diagram showing the dependency of the luminance / current density on the thickness of the light emitting layer when the light emitting substance is used as a parameter for the organic thin film light emitting device. It can be seen that there is an optimum emissive layer thickness that achieves the desired brightness at the minimum current density. FIG. 5 is a diagram showing the dependency of the luminance / current density on the thickness of the charge injection layer when the light emitting substance is used as a parameter for the organic thin film light emitting device. It can be seen that the brightness / current density of the organic thin film light emitting device does not change regardless of the film thickness of the charge injection layer.
【００１０】図６は有機薄膜発光素子につき所定の電流
密度における電荷注入層電圧の電荷注入層膜厚依存性を
示す線図である。電荷注入層の膜厚に比例して電荷注入
層の電圧が変化することがわかる。以上のようにして有
機薄膜発光素子を所望の輝度において最小の電流密度で
発光させる発光層膜厚が存在しこの膜厚と電流密度で規
定される発光層電圧が一義的に決まる。電荷注入層の電
圧は上記電流密度において電荷注入層の膜厚により決ま
るから電荷注入層の膜厚を調整して素子の輝度／電流密
度特性に影響をあたえることなく画素の駆動電圧を一定
にすることが可能となる。FIG. 6 is a diagram showing the dependence of the charge injection layer voltage on the charge injection layer film thickness at a predetermined current density for the organic thin film light emitting device. It can be seen that the voltage of the charge injection layer changes in proportion to the thickness of the charge injection layer. As described above, there is a light emitting layer film thickness that allows the organic thin film light emitting device to emit light with a minimum current density at a desired luminance, and the light emitting layer voltage defined by this film thickness and current density is uniquely determined. Since the voltage of the charge injection layer is determined by the film thickness of the charge injection layer at the above current density, the film thickness of the charge injection layer is adjusted to make the pixel drive voltage constant without affecting the luminance / current density characteristics of the device. It becomes possible.
【００１１】[0011]
【実施例】図１はこの発明の実施例に係る有機薄膜発光
素子を示す断面図である。図２はこの発明の異なる実施
例に係る有機薄膜発光素子を示す断面図である。図３は
この発明のさらに異なる実施例に係る有機薄膜発光素子
を示す断面図である。1 is a sectional view showing an organic thin film light emitting device according to an embodiment of the present invention. FIG. 2 is a sectional view showing an organic thin film light emitting device according to another embodiment of the present invention. FIG. 3 is a sectional view showing an organic thin film light emitting device according to another embodiment of the present invention.
【００１２】１は絶縁性基板、２は正極、３は正孔注入
層、４は発光層、５電子注入層は、６は負極、７は電源
である。絶縁性基板１は素子の支持体でガラス，樹脂等
が用いられる。正極２は効率良く正孔を注入し、低抵抗
で可視光に対して透明で環境安定性が高いことが必要で
ある。正極としてはインジウムスズ酸化物（ＩＴＯ），
酸化スズ（ＳｎＯ2 ），酸化亜鉛等の透明導電膜やポリ
ピロール，ポリチオフェンなどの導電性高分子が用いら
れる。成膜方法は抵抗加熱蒸着、電子ビ−ム蒸着、スパ
ッタ法，キャスティング，電解重合．化学重合法が用い
られる。正極２の膜厚は透明性を持たせるために、１０
〜５００ｎｍの厚さにすることが望ましい。Reference numeral 1 is an insulating substrate, 2 is a positive electrode, 3 is a hole injection layer, 4 is a light emitting layer, 5 is an electron injection layer, 6 is a negative electrode, and 7 is a power source. The insulating substrate 1 is a support for the element and is made of glass, resin, or the like. The positive electrode 2 is required to efficiently inject holes, have low resistance, be transparent to visible light, and have high environmental stability. Indium tin oxide (ITO) as the positive electrode,
Transparent conductive films such as tin oxide (SnO 2 ) and zinc oxide, and conductive polymers such as polypyrrole and polythiophene are used. The film formation method is resistance heating vapor deposition, electron beam vapor deposition, sputtering method, casting, electrolytic polymerization. A chemical polymerization method is used. The thickness of the positive electrode 2 is 10 in order to have transparency.
It is desirable to have a thickness of ~ 500 nm.
【００１３】正孔注入層３は正孔を効率良く輸送し、且
つ注入することが必要で発光した光の発光極大波長領域
においてできるだけ透明であることが望ましい。成膜方
法としてスピンコ−ト、キャスティング、ＬＢ法、抵抗
加熱蒸着、電子ビ−ム蒸着等があるが抵抗加熱蒸着が一
般的である。膜厚は１０〜５００ｎｍの厚さであり好適
にはｌ０ないし１００ｎｍの最適値に設定される。正孔
注入物質としては化学式（Ｉ−１）ないし化学式（Ｉ−
７）に示す有機物質またはその誘導体が用いられる。The hole injection layer 3 is required to efficiently transport and inject holes, and it is desirable that the hole injection layer 3 is as transparent as possible in the maximum emission wavelength region of the emitted light. The film forming method includes spin coating, casting, LB method, resistance heating evaporation, electron beam evaporation and the like, but resistance heating evaporation is common. The film thickness is 10 to 500 nm, and is preferably set to an optimum value of 10 to 100 nm. As the hole injecting substance, the chemical formula (I-1) to the chemical formula (I-
The organic substance or its derivative shown in 7) is used.
【００１４】代表的な正孔注入物質が以下に示される。Representative hole injecting materials are shown below.
【００１５】[0015]
【化１】 [Chemical 1]
【００１６】発光層４は正孔注入層３または正極２から
注入された正孔と、負極６または電子注入層５より注入
された電子の再結合により効率良く発光を行う。成膜方
法はスピンコ−ト、キャスティング、ＬＢ法、抵抗加熱
蒸着、電子ビ−ム蒸着、分子線エピタキシ等があるが抵
抗加熱蒸着、分子線エピタキシが好ましい。膜厚は１０
ないし５００ｎｍであるが好適には１０ないし１００ｎ
ｍの最適値に設定される。発光物質としては化学式（II
−１）ないし化学式（II−５）に示すような有機物質ま
たはその誘導体が用いられる。The light emitting layer 4 efficiently emits light by recombination of holes injected from the hole injection layer 3 or the positive electrode 2 and electrons injected from the negative electrode 6 or the electron injection layer 5. The film forming method includes spin coating, casting, LB method, resistance heating evaporation, electron beam evaporation, molecular beam epitaxy and the like, but resistance heating evaporation and molecular beam epitaxy are preferable. Film thickness is 10
To 500 nm, but preferably 10 to 100 n
It is set to the optimum value of m. Chemical formula (II
-1) to organic compounds represented by the chemical formula (II-5) or derivatives thereof are used.
【００１７】[0017]
【化２】 [Chemical 2]
【００１８】負極６は電子を効率良く有機層に注入する
ことが必要である。成膜方法としては抵抗加熱蒸着，電
子ビーム蒸着，スパッタ法が用いられる。負極用材料と
しては、仕事関数の小さいＭｇ，Ａｇ，Ｉｎ，Ｃａ，Ａ
ｌ等およびこれらの合金，積層体等が用いられる。電子
注入層５は電子を効率良く輸送し、且つ注入することが
必要で発光した光の発光極大波長領域においてできるだ
け透明であることが望ましい。成膜方法としてスピンコ
−ト、キャスティング、ＬＢ法、抵抗加熱蒸着、電子ビ
−ム蒸着等があるが抵抗加熱蒸着が一般的である。膜厚
は５〜５００ｎｍの厚さであり好適にはｌ０ないし１０
０ｎｍの最適値に設定される。電子注入層質としては化
学式（III −１）ないし化学式（III −３）に示すよう
な有機物質またはその誘導体が用いられる。The negative electrode 6 needs to efficiently inject electrons into the organic layer. As a film forming method, resistance heating evaporation, electron beam evaporation, or sputtering method is used. As the material for the negative electrode, Mg, Ag, In, Ca, A having a small work function is used.
1 and the like and alloys and laminates thereof are used. The electron injection layer 5 needs to efficiently transport and inject electrons, and is preferably as transparent as possible in the emission maximum wavelength region of the emitted light. The film forming method includes spin coating, casting, LB method, resistance heating evaporation, electron beam evaporation and the like, but resistance heating evaporation is common. The film thickness is 5 to 500 nm, and preferably 10 to 10
It is set to the optimum value of 0 nm. As the electron injection layer quality, an organic substance or a derivative thereof as shown in the chemical formulas (III-1) to (III-3) is used.
【００１９】代表的な電子注入物質が以下に示される。Representative electron injecting materials are shown below.
【００２０】[0020]
【化３】 [Chemical 3]
【００２１】実施例１ 図１はこの発明の実施例に係る有機薄膜発光素子を示す
断面図である。この有機薄膜発光素子は赤，緑，青の各
画素を有する。厚さ１．１ｍｍのガラス基板１上に膜厚
約１００ｎｍ，線幅２ｍｍ，線間隔１ｍｍのITO からな
るストライプ状の正極２を電子ビーム蒸着法にて設け
た。Example 1 FIG. 1 is a sectional view showing an organic thin film light emitting device according to an example of the present invention. This organic thin film light emitting element has red, green and blue pixels. On a glass substrate 1 having a thickness of 1.1 mm, a striped positive electrode 2 made of ITO having a film thickness of about 100 nm, a line width of 2 mm and a line interval of 1 mm was provided by an electron beam evaporation method.
【００２２】正孔注入物質としては化学式（Ｉ−１）に
示される化合物を用いた。負極はMgIn合金を用いた。正
孔注入層と発光層と負極の成膜には抵抗加熱蒸着法を用
いた。発光物質，正孔注入層膜厚，発光層膜厚，輝度，
電流密度が表１に示される。駆動電圧は８Ｖを印加し
た。As the hole injecting substance, the compound represented by the chemical formula (I-1) was used. MgIn alloy was used for the negative electrode. A resistance heating vapor deposition method was used for forming the hole injection layer, the light emitting layer, and the negative electrode. Luminescent material, hole injection layer thickness, luminescent layer thickness, brightness,
The current density is shown in Table 1. A drive voltage of 8V was applied.
【００２３】[0023]
【表１】 [Table 1]
【００２４】実施例２ 図２はこの発明の異なる実施例に係る有機薄膜発光素子
を示す断面図である。この有機薄膜発光素子は緑，青の
各画素を有する。厚さ１．１ｍｍのガラス基板１上に膜
厚約１００ｎｍ，線幅２ｍｍ，線間隔１ｍｍのITO から
なるストライプ状の正極２を電子ビーム蒸着法にて設け
た。Embodiment 2 FIG. 2 is a sectional view showing an organic thin film light emitting device according to another embodiment of the present invention. This organic thin film light emitting device has green and blue pixels. On a glass substrate 1 having a thickness of 1.1 mm, a striped positive electrode 2 made of ITO having a film thickness of about 100 nm, a line width of 2 mm and a line interval of 1 mm was provided by an electron beam evaporation method.
【００２５】電子注入物質は化学式（III −１）に示さ
れる化合物を用いた。負極はMgIn合金を用いた。電子注
入層と発光層と負極の成膜には抵抗加熱蒸着法を用い
た。発光物質，正孔注入層膜厚，発光層膜厚，輝度，電
流密度が表２に示される。駆動電圧は８Ｖを印加した。As the electron injecting substance, the compound represented by the chemical formula (III-1) was used. MgIn alloy was used for the negative electrode. A resistance heating vapor deposition method was used for forming the electron injection layer, the light emitting layer, and the negative electrode. Table 2 shows the light emitting substance, the hole injection layer film thickness, the light emitting layer film thickness, the brightness, and the current density. A drive voltage of 8V was applied.
【００２６】[0026]
【表２】 [Table 2]
【００２７】実施例３ 図３はこの発明のさらに異なる実施例に係る有機薄膜発
光素子を示す断面図である。この有機薄膜発光素子は
赤，緑，青の各画素を有する。厚さ１．１ｍｍのガラス
基板１上に膜厚約１００ｎｍ，線幅２ｍｍ，線間隔１ｍ
ｍのITO からなるストライプ状の正極２を電子ビーム蒸
着法にて設けた。Example 3 FIG. 3 is a cross-sectional view showing an organic thin film light emitting device according to another example of the present invention. This organic thin film light emitting element has red, green and blue pixels. Film thickness of about 100 nm, line width 2 mm, line spacing 1 m on 1.1 mm thick glass substrate 1.
m strips of ITO 2 were provided by electron beam evaporation.
【００２８】正孔注入物質には化学式（Ｉ−１）に示す
化合物を用いた。電子注入物質は化学式（III −１）に
示される化合物を用いた。負極はMgIn合金を用いた。正
孔注入層と電子注入層と発光層と負極の成膜には抵抗加
熱蒸着法を用いた。発光物質，正孔注入層膜厚，電子注
入層膜厚，発光層膜厚，輝度，電流密度が表３に示され
る。駆動電圧は１０Ｖを印加した。As the hole injecting substance, the compound represented by the chemical formula (I-1) was used. As the electron injecting substance, the compound represented by the chemical formula (III-1) was used. MgIn alloy was used for the negative electrode. A resistance heating vapor deposition method was used for forming the hole injection layer, the electron injection layer, the light emitting layer, and the negative electrode. Table 3 shows the light emitting material, the hole injection layer film thickness, the electron injection layer film thickness, the light emitting layer film thickness, the brightness, and the current density. A driving voltage of 10V was applied.
【００２９】[0029]
【表３】 [Table 3]
【００３０】[0030]
【発明の効果】この発明によれば、有機薄膜を用いる電
場発光素子であって、画素のアレーからなり、各画素は
（１）絶縁性支持体と、（２）正極と、（３）発光層
と、（４）電荷注入層と、（５）負極を包含し、絶縁性
支持体は素子の支持体であり、発光層は所定の波長の発
光を行う発光物質を含んで所望の発光層輝度を最小の電
流密度で実現する膜厚を有し、電荷注入層は正孔注入層
と電子注入層のうちの少なくとも一つからなり、電荷注
入層は膜厚により電荷注入層に印加される電圧を調節
し、正極と負極は画素の駆動電圧が印加されるものであ
るとするので、発光層の最適膜厚において最小電流密度
で規定される発光層電圧が一義的に決まる。電荷注入層
の電圧は上記電流密度において電荷注入層の膜厚により
調節されるから電荷注入層の膜厚を調整することにより
素子の輝度／電流密度特性に影響をあたえることなく画
素の駆動電圧を一定にすることが可能となる。According to the present invention, there is provided an electroluminescent device using an organic thin film, which comprises an array of pixels, each pixel having (1) an insulating support, (2) a positive electrode, and (3) light emission. Layer, (4) charge injection layer, and (5) negative electrode, the insulative support is a support for the device, and the light emitting layer contains a light emitting substance that emits light of a predetermined wavelength. The charge injection layer has a film thickness that realizes brightness with a minimum current density, and the charge injection layer includes at least one of a hole injection layer and an electron injection layer, and the charge injection layer is applied to the charge injection layer according to the film thickness. Since the voltage is adjusted and the driving voltage of the pixel is applied to the positive electrode and the negative electrode, the light emitting layer voltage defined by the minimum current density is uniquely determined in the optimum film thickness of the light emitting layer. The voltage of the charge injection layer is adjusted by the film thickness of the charge injection layer at the above current density. Therefore, by adjusting the film thickness of the charge injection layer, the driving voltage of the pixel can be controlled without affecting the brightness / current density characteristics of the device. It becomes possible to make it constant.
【図１】この発明の実施例に係る有機薄膜発光素子を示
す断面図FIG. 1 is a sectional view showing an organic thin film light emitting device according to an embodiment of the present invention.
【図２】この発明の異なる実施例に係る有機薄膜発光素
子を示す断面図FIG. 2 is a sectional view showing an organic thin film light emitting device according to another embodiment of the present invention.
【図３】この発明のさらに異なる実施例に係る有機薄膜
発光素子を示す断面図FIG. 3 is a sectional view showing an organic thin film light emitting device according to still another embodiment of the present invention.
【図４】有機薄膜発光素子につき発光物質をパラメータ
としたときの輝度／電流密度の発光層膜厚依存性を示す
線図FIG. 4 is a diagram showing the dependency of luminance / current density on the thickness of a light emitting layer when a light emitting substance is used as a parameter for an organic thin film light emitting device.
【図５】有機薄膜発光素子につき発光物質をパラメータ
としたときの輝度／電流密度の電荷注入層膜厚依存性を
示す線図FIG. 5 is a graph showing the dependence of luminance / current density on the thickness of a charge injection layer when a light emitting substance is used as a parameter for an organic thin film light emitting device.
【図６】有機薄膜発光素子につき所定の電流密度におけ
る電圧の電荷注入層膜厚依存性を示す線図FIG. 6 is a graph showing the dependence of voltage on the charge injection layer thickness at a given current density for an organic thin film light emitting device.
１ 基板 ２ 正極 ３ 正孔注入層 ４ 発光層 ５ 電子注入層 ６ 負極 ７ 電源 1 substrate 2 positive electrode 3 hole injection layer 4 light emitting layer 5 electron injection layer 6 negative electrode 7 power supply
Claims (1)
画素のアレーからなり、各画素は （１）絶縁性基板と、 （２）正極と、 （３）発光層と、 （４）電荷注入層と、 （５）負極を包含し、 絶縁性基体は素子の支持体であり、 発光層は所定の波長の発光を行う発光物質を含んで所望
の発光輝度を最小の電流密度で実現する膜厚を有し、 電荷注入層は正孔注入層と電子注入層のうちの少なくと
も一つからなり、電荷注入層は膜厚により電荷注入層に
印加される電圧を調節し、 正極と負極は画素の駆動電圧が印加されるものであるこ
とを特徴とする有機薄膜発光素子。1. An electroluminescent device using an organic thin film, comprising:
Each pixel is composed of an array of pixels, and each pixel includes (1) an insulating substrate, (2) a positive electrode, (3) a light emitting layer, (4) a charge injection layer, and (5) a negative electrode. It is a support for the device, and the light emitting layer contains a light emitting substance that emits light of a predetermined wavelength and has a thickness that achieves a desired light emission brightness with a minimum current density. The charge injection layer is formed of at least one of the injection layers, and the charge injection layer controls a voltage applied to the charge injection layer according to a film thickness, and the positive and negative electrodes are applied with a pixel driving voltage. Organic thin film light emitting device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5233973A JPH0794278A (en) | 1993-09-21 | 1993-09-21 | Organic thin film light emitting element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5233973A JPH0794278A (en) | 1993-09-21 | 1993-09-21 | Organic thin film light emitting element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0794278A true JPH0794278A (en) | 1995-04-07 |
Family
ID=16963545
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5233973A Pending JPH0794278A (en) | 1993-09-21 | 1993-09-21 | Organic thin film light emitting element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0794278A (en) |
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