JPH01243394A - Thin-film el device - Google Patents
Thin-film el deviceInfo
- Publication number
- JPH01243394A JPH01243394A JP63069491A JP6949188A JPH01243394A JP H01243394 A JPH01243394 A JP H01243394A JP 63069491 A JP63069491 A JP 63069491A JP 6949188 A JP6949188 A JP 6949188A JP H01243394 A JPH01243394 A JP H01243394A
- Authority
- JP
- Japan
- Prior art keywords
- film
- thick
- emitting layer
- light emitting
- insulating 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 description 14
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims abstract description 4
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 claims abstract 5
- 229910052751 metal Inorganic materials 0.000 claims abstract 2
- 239000002184 metal Substances 0.000 claims abstract 2
- 239000000463 material Substances 0.000 claims description 8
- 239000010408 film Substances 0.000 claims description 6
- 229910052783 alkali metal Inorganic materials 0.000 claims description 3
- 150000001340 alkali metals Chemical class 0.000 claims description 3
- 239000000758 substrate Substances 0.000 claims description 3
- 229910001515 alkali metal fluoride Inorganic materials 0.000 claims description 2
- 239000003513 alkali Substances 0.000 claims 1
- 239000002585 base Substances 0.000 claims 1
- 238000005566 electron beam evaporation Methods 0.000 abstract description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 4
- 239000011521 glass Substances 0.000 abstract description 4
- 229910052760 oxygen Inorganic materials 0.000 abstract description 4
- 239000001301 oxygen Substances 0.000 abstract description 4
- 238000004544 sputter deposition Methods 0.000 abstract description 4
- 239000005132 Calcium sulfide based phosphorescent agent Substances 0.000 abstract description 2
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 238000009413 insulation Methods 0.000 abstract 4
- 238000000034 method Methods 0.000 abstract 2
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 abstract 2
- 238000001704 evaporation Methods 0.000 abstract 1
- 230000008020 evaporation Effects 0.000 abstract 1
- 230000006866 deterioration Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000001017 electron-beam sputter deposition Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 150000002222 fluorine compounds Chemical class 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Electroluminescent Light Sources (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は薄膜ＥＬ素子に係り、特に、発光特性の経時変
化の少ない、安定なＥＬ素子構造に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thin film EL device, and particularly to a stable EL device structure with little change in luminescent properties over time.
薄膜ＥＬ素子は自己発光型で表示品質の良い平面デイス
プレィとしてコンピュータ端末や計測装置の表示部に用
いられている。薄膜ＥＬ素子の構造を第２図の模式図に
よって説明する。ガラス基板１の上にＩ Ｔ Ｏ（Ｉｎ
ｄｉｕｍ−Ｔｉｎ−Ｏｘｉｄｅ）等の下部透明電極２が
形成されている。この上にＹ２Ｏ３゜５ｉＯｚ、ＡＱ２
０３．ＴａｚＯ５，５ｉａＮ４．あるいは、これらの組
み合わせからなる第一絶縁層７が電子ビーム蒸着、ある
いは、スパッタリングによって形成されている。この上
にはＩＩ−ＶＩ族化合物（ＺｎＳ、ＣａＳ、ＳｒＳ等）
を母体とし、これに活性物質（Ｍｎ、Ｔｂ、Ｅｕ、Ｃｅ
または。Thin film EL elements are self-luminous and are used as flat displays with good display quality in display units of computer terminals and measuring devices. The structure of the thin film EL element will be explained with reference to the schematic diagram of FIG. ITO (In
A lower transparent electrode 2 made of dium-Tin-Oxide or the like is formed. On top of this, Y2O3゜5iOz, AQ2
03. TazO5,5iaN4. Alternatively, the first insulating layer 7 made of a combination of these is formed by electron beam evaporation or sputtering. On top of this are II-VI group compounds (ZnS, CaS, SrS, etc.)
is used as a matrix, and active substances (Mn, Tb, Eu, Ce
or.
これらの硫化物、酸化物、燐化物、ハロゲン化物等）を
適量混合した発光Ｍ４が、電子ビーム蒸着、スパッタリ
ング、あるいは、ＣＶＤ （化学気相成長法）により形
成されている。さらに、この上には、第一絶縁層と同様
な第二絶縁層８が形成されており、その上に、ＡＩＤ、
Ａｕ、ＩＴＯ等の上部電極５が、ガラス基板１上の下部
電極２と直角方向にストライプ状に形成されている。こ
のような構造の薄膜ＥＬ素子は、たとえば、日経エレク
トロニクス１９８１．１１ 、９．Ｎ１１２７７ Ｐ
８６（１９８１）に記載されている。下部電極２と上
部電極５の間に交流電圧を印加すると、交差した部分（
画素）のみが発光するので１文字やグラフィックス表示
等のデイスプレィ機能が実現できる。The light-emitting M4, which is a mixture of appropriate amounts of these sulfides, oxides, phosphides, halides, etc., is formed by electron beam evaporation, sputtering, or CVD (chemical vapor deposition). Furthermore, a second insulating layer 8 similar to the first insulating layer is formed on this, and on top of this, AID,
An upper electrode 5 made of Au, ITO, or the like is formed in a stripe shape on the glass substrate 1 in a direction perpendicular to the lower electrode 2 . A thin film EL element having such a structure is described, for example, in Nikkei Electronics 1981.11, 9. N11277P
86 (1981). When an AC voltage is applied between the lower electrode 2 and the upper electrode 5, the crossing portion (
Since only the pixels (pixels) emit light, display functions such as displaying single characters or graphics can be realized.
薄膜ＥＬ素子の絶縁層には、多くの場合、酸化物系の材
料が使われている。しかし、Ｃａｂ：Ｅｕ発光層を用い
た赤色ＥＬ素子では、輝度−電圧曲線に極大が現われる
。あるいは、輝度の低下が大きいなど、安定性に問題が
あることが、シャープ技報第３７号１９８７年Ｐ１７に
論じられている。In many cases, oxide-based materials are used for the insulating layer of thin-film EL devices. However, in a red EL element using a Cab:Eu light emitting layer, a maximum appears in the brightness-voltage curve. Alternatively, it is discussed in Sharp Technical Report No. 37, 1987, page 17 that there is a problem with stability, such as a large decrease in brightness.
このようなＣａＳ：Ｅｕ発光層を用いたＥＬ素子での特
性劣化に対しては１発光層に接する絶縁層材料に５ｉａ
Ｎ＋を用いることで、特性が改善されることが、上記文
献に記述されている。また、Ｚ ｎ Ｓ ： Ｍ ｎ発
光層を用いた黄橙色ＥＬ素子でも発光層と酸化物絶縁層
の中間にＳ １ａＮａのバッファ層を入れることにより
、発光特性が安定することが昭和６２年秋季応用物理学
会予稿集Ｐ 、８５６に述べられている。同様に、アル
カリ土類金属の沸化物をバッファ層に用いた例も、特開
昭６０−２５７０９６号公報で開示されている。In order to prevent characteristic deterioration in an EL device using such a CaS:Eu light emitting layer, it is necessary to
The above document describes that the characteristics are improved by using N+. Furthermore, even in a yellow-orange EL element using a ZnS:Mn light-emitting layer, the light-emitting characteristics were stabilized by inserting a buffer layer of S1aNa between the light-emitting layer and the oxide insulating layer, as reported in the autumn application of 1988. It is stated in Proceedings of the Physical Society of Japan P, 856. Similarly, an example in which a fluoride of an alkaline earth metal is used for the buffer layer is also disclosed in JP-A-60-257096.
上記従来技術により、ＥＬ発光特性の経時変化は減少し
たが、動作初期における劣化は防ぐことができていない
。また、５ｉａＮａ膜は、膜中の圧力が大きいため膜は
がれ等の欠陥が生じやすい。Although the above-mentioned conventional technology has reduced the change over time in the EL light emission characteristics, it has not been possible to prevent deterioration in the initial stage of operation. Furthermore, since the pressure inside the 5iaNa film is high, defects such as film peeling are likely to occur.
本発明の目的は、より発光特性の安定した薄膜ＥＬ素子
を提供することにある。An object of the present invention is to provide a thin film EL element with more stable light emitting characteristics.
上記目的は１発光層に接する絶縁層材料として、アルカ
リ金属の沸化物を用いることにより達成される。The above object is achieved by using an alkali metal fluoride as the insulating layer material in contact with one light-emitting layer.
アルカリ金属の沸化物は、化学的に安定であり酸化され
にくい。そのため１発光層に接する絶縁層に上記材料を
用いることにより、大気中、あるいは、酸素を含む絶縁
層材料から発光層中への酸素の拡散を防ぐことができる
のでＥＬ発光特性を安定化することができる。Fluorides of alkali metals are chemically stable and difficult to oxidize. Therefore, by using the above-mentioned material for the insulating layer in contact with one light-emitting layer, it is possible to prevent oxygen from diffusing into the light-emitting layer from the atmosphere or from the oxygen-containing insulating layer material, thereby stabilizing the EL light-emitting characteristics. Can be done.
以下、本発明の一実施例を第１図により説明する。 An embodiment of the present invention will be described below with reference to FIG.
厚さ１ ｎａ ｔのコーニング＃ ７０５９ガラス１上
に下部透明電極として、ＩＴＯをスパッタリングによっ
て０．２５ μｍの厚さに形成し、ストライプ状にフォ
トエツチングする。この上にスパッタリングによりＴａ
ｚＯ５の第一絶縁層３を０．５μｍ形成した。さらに、
電子ビーム蒸着法により綿化リチウム（ＬｉＦ）膜６を
０．１μｍ形成した。この上に、発光層４としてＣａＳ
：Ｅｕを電子ビーム蒸着法により約１μｍ形成した後、
再び、ＬｉＦ膜６ＴａｚＯｓ第二絶縁層３を形成し、最
後に上部電極５としてＡＱを抵抗加熱蒸着により形成し
た。ITO is formed to a thickness of 0.25 μm by sputtering as a lower transparent electrode on Corning #7059 glass 1 having a thickness of 1 nat, and photoetched in a stripe shape. On top of this, Ta was added by sputtering.
A first insulating layer 3 of zO5 was formed to a thickness of 0.5 μm. moreover,
A 0.1 μm thick lithium cotton (LiF) film 6 was formed by electron beam evaporation. On top of this, CaS is used as the light emitting layer 4.
: After forming Eu to a thickness of about 1 μm by electron beam evaporation,
Again, a LiF film 6TazOs second insulating layer 3 was formed, and finally, an upper electrode 5 of AQ was formed by resistance heating vapor deposition.
発光層に接する絶縁層の材料を変えたＥＬ素子の輝度の
経時変化を第３図に示す。ＴａｚＯらを用いた素子では
、輝度の低下が著しい。５ｉａＮ４を用いた素子では、
輝度の低下は少なくなったが、初期特性の劣化は解決で
きない。しかし、ＬｉＦを用いた素子では初期劣化がほ
とんどない安定な特性が得られている。FIG. 3 shows changes over time in luminance of EL elements in which the material of the insulating layer in contact with the light emitting layer was changed. In the device using TazO et al., the brightness decreases significantly. In the element using 5iaN4,
Although the decrease in brightness has been reduced, the deterioration of the initial characteristics cannot be resolved. However, elements using LiF have stable characteristics with almost no initial deterioration.
発光層に接する絶縁層材料は、ＬｉＦのほかＮａＦ、Ｋ
Ｆなどのアルカリ金属の沸化物に、ＥＬ発光特性安定化
の効果が認められる。Insulating layer materials in contact with the light emitting layer include LiF, NaF, and K.
Fluorides of alkali metals such as F have been found to have the effect of stabilizing EL emission characteristics.
本発明によれば、発光層中への酸素の拡散を防ぐことが
できるので、ＥＬ発光特性の経時変化を安定化すること
ができる。According to the present invention, it is possible to prevent oxygen from diffusing into the light emitting layer, so that changes over time in EL light emission characteristics can be stabilized.
第１図は、本発明の一実施例のｒ＝ｉＦｖを用いた薄膜
ＥＬ素子の断面図、第２図は、一般的な交流駆動型薄膜
ＥＬ索子の断面図、第３図は、異なる絶縁層材料を用い
たＥＬ素子の輝度の経時変化を示す図である。
１・・・ガラス基板、２・・・下部電極、３・・・Ｔａ
ｚＯ５、４−Ｃａ５：Ｅｕ、５・・・上部電１，６−Ｌ
１Ｆ、７・・・第一絶縁層、８・・・第二絶縁層。FIG. 1 is a cross-sectional view of a thin film EL element using r=iFv according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a general AC-driven thin film EL element, and FIG. FIG. 3 is a diagram showing a change in luminance over time of an EL element using an insulating layer material. 1... Glass substrate, 2... Lower electrode, 3... Ta
zO5,4-Ca5:Eu,5... Upper electrode 1,6-L
1F, 7... first insulating layer, 8... second insulating layer.
Claims (3)
縁層及び上部電極を順次積層した薄膜ＥＬ素子において
、 前記第一絶縁層および／または前記第二絶縁層の一部あ
るいは全部をアルカリ金属の沸化物からなる膜で構成し
、前記アルカリ金属の沸化物からなる膜を前記発光層と
接するようにしたことを特徴とする薄膜ＥＬ素子。1. In a thin film EL device in which a lower electrode, a first insulating layer, a light-emitting layer, a second insulating layer, and an upper electrode are sequentially laminated on a substrate, part or all of the first insulating layer and/or the second insulating layer is alkali-based. 1. A thin film EL device comprising a film made of a fluoride of a metal, the film made of a fluoride of an alkali metal being in contact with the light emitting layer.
ことを特徴とする特許請求の範囲第１項記載の薄膜ＥＬ
素子。2. The thin film EL according to claim 1, wherein the alkali metal fluoride is lithium fluoride.
element.
Ｓであることを特徴とする特許請求の範囲第１項または
第２項記載の薄膜ＥＬ素子。3. The base material of the light emitting layer is CaS or Sr.
The thin film EL device according to claim 1 or 2, wherein the thin film EL device is S.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63069491A JPH01243394A (en) | 1988-03-25 | 1988-03-25 | Thin-film el device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63069491A JPH01243394A (en) | 1988-03-25 | 1988-03-25 | Thin-film el device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01243394A true JPH01243394A (en) | 1989-09-28 |
Family
ID=13404230
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63069491A Pending JPH01243394A (en) | 1988-03-25 | 1988-03-25 | Thin-film el device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01243394A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7952273B2 (en) | 2006-12-06 | 2011-05-31 | Electronics And Telecommunications Research Institute | Organic light emitting diode device |
-
1988
- 1988-03-25 JP JP63069491A patent/JPH01243394A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7952273B2 (en) | 2006-12-06 | 2011-05-31 | Electronics And Telecommunications Research Institute | Organic light emitting diode device |
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