JPH0318320B2 - - Google Patents
Info
- Publication number
- JPH0318320B2 JPH0318320B2 JP57114473A JP11447382A JPH0318320B2 JP H0318320 B2 JPH0318320 B2 JP H0318320B2 JP 57114473 A JP57114473 A JP 57114473A JP 11447382 A JP11447382 A JP 11447382A JP H0318320 B2 JPH0318320 B2 JP H0318320B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- light emitting
- emitting layer
- thin film
- 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.)
- Expired - Lifetime
Links
- 239000010409 thin film Substances 0.000 claims description 24
- 238000010586 diagram Methods 0.000 description 5
- 230000005684 electric field Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000010408 film Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000008188 pellet Substances 0.000 description 3
- -1 Si 3 N 4 Inorganic materials 0.000 description 2
- 229910010413 TiO 2 Inorganic materials 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 238000005566 electron beam evaporation Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000005283 ground state Effects 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- SBIBMFFZSBJNJF-UHFFFAOYSA-N selenium;zinc Chemical compound [Se]=[Zn] SBIBMFFZSBJNJF-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- NCGICGYLBXGBGN-UHFFFAOYSA-N 3-morpholin-4-yl-1-oxa-3-azonia-2-azanidacyclopent-3-en-5-imine;hydrochloride Chemical compound Cl.[N-]1OC(=N)C=[N+]1N1CCOCC1 NCGICGYLBXGBGN-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000004020 luminiscence type Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 238000005019 vapor deposition process Methods 0.000 description 1
Description
【発明の詳細な説明】
本発明は交流電界の印加に依つてEL（Electro
Luminescence）発光を呈する薄膜EL素子の構造
に関し、特に外部発光効率を改善することを企図
するものである。[Detailed Description of the Invention] The present invention utilizes EL (Electro
Regarding the structure of a thin film EL element that emits light (luminescence), it is intended to improve the external light emitting efficiency in particular.
従来、交流動作の薄膜EL素子として、絶縁耐
圧、発光効率及び動作の安定性等を高めるために
0.1〜2.0wt％のMn（あるいはCu、Al、Br等）を
ドープしたZnS、ZnSe等の半導体発光層をY2O3、
TiO2等の誘電体薄膜でサンドイツチした三層構
造ZnS：Mn（又はZnSe：Mn）EL素子が開発さ
れ、発光諸特性の向上が確かめられている。この
薄膜EL素子はＫHzの交流電界印加によつて高輝
度発光し、しかも長寿命であるという特徴を有し
ている。 Conventionally, AC-operated thin-film EL elements were used to improve dielectric strength, luminous efficiency, and operational stability.
A semiconductor light-emitting layer such as ZnS or ZnSe doped with 0.1 to 2.0 wt% Mn (or Cu, Al, Br, etc.) is made of Y 2 O 3 ,
A three-layer structure ZnS:Mn (or ZnSe:Mn) EL device sandwiched with a dielectric thin film such as TiO 2 has been developed, and improvements in various light-emitting properties have been confirmed. This thin-film EL element emits high-intensity light when an alternating current electric field of KHz is applied, and has a long lifespan.
またこの薄膜EL素子の発光に関しては印加電
圧を昇圧していく過程と高電圧側より降圧してい
く過程で、同じ印加電圧に対して発光輝度が異な
るといつたヒステリシス特性を有していることが
発見され、そしてこのヒステリシス特性を有する
薄膜EL素子に印加電圧を昇圧する過程に於いて、
光、電界、熱等が付与されると薄膜EL素子はそ
の強度に対応した発光輝度の状態に励起され、
光、電界、熱等を除去して元の状態に戻しても発
光輝度は高くなつた状態で維持される、いわゆる
メモリー現象が表示技術の新たな利用分野を開拓
するに至つた。 Furthermore, regarding the light emission of this thin film EL element, it has a hysteresis characteristic in which the light emission brightness differs for the same applied voltage in the process of increasing the applied voltage and in the process of decreasing the voltage from the high voltage side. was discovered, and in the process of increasing the voltage applied to a thin film EL element with this hysteresis characteristic,
When light, electric field, heat, etc. are applied, the thin film EL element is excited to a state of luminance corresponding to the intensity,
The so-called memory phenomenon, in which the luminance remains high even when light, electric field, heat, etc. are removed and the original state is restored, has led to the development of new fields of application for display technology.
薄膜発EL素子の１例としZnS：Mn薄膜EL素
子の基本構造を第１図に示す。 Figure 1 shows the basic structure of a ZnS:Mn thin film EL device, which is an example of a thin film EL device.
第１図に基いて薄膜EL素子の構造を具体的に
説明すると、ガラス基板１上にIn2O3、SnO2等の
透明電極２、さらにその上に積層してY2O3、
TiO2、Al2O3、Si3N4、SiO2等からなる第１の誘
電体層３がスパツタあるいは電子ビーム蒸着法等
により重畳形成されている。第１の誘電体層３上
にはZnS：Mn焼結ペレツトを電子ビーム蒸着す
ることにより得られるZnS発光層４が形成されて
いる。この時蒸着用のZnS：Mn焼結ペレツトに
は活性物質となるMnが目的に応じた濃度に設定
されたペレツトが使用される。 The structure of the thin film EL element will be explained in detail based on FIG. 1. A transparent electrode 2 made of In 2 O 3 , SnO 2 , etc. is placed on a glass substrate 1, and Y 2 O 3 , etc.
A first dielectric layer 3 made of TiO 2 , Al 2 O 3 , Si 3 N 4 , SiO 2 or the like is formed in an overlapping manner by sputtering or electron beam evaporation. A ZnS light emitting layer 4 is formed on the first dielectric layer 3 by electron beam evaporation of ZnS:Mn sintered pellets. At this time, the ZnS:Mn sintered pellets used for deposition are pellets in which the concentration of Mn, which is an active substance, is set to suit the purpose.
ZnS発光層４上には第１の誘電体層３と同様の
材料群より選定された材質からなる第２の誘電体
層５が積層され、更にその上にAl等からなる背
面電極６が蒸着形成されている。透明電極２と背
面電極６は交流電源７に接続され、薄膜EL素子
が駆動される。 A second dielectric layer 5 made of a material selected from the same material group as the first dielectric layer 3 is laminated on the ZnS light emitting layer 4, and a back electrode 6 made of Al or the like is further deposited on top of the second dielectric layer 5. It is formed. The transparent electrode 2 and the back electrode 6 are connected to an AC power source 7 to drive the thin film EL element.
電極２，６間にAC電圧を印加すると、ZnS発
光層４の両側の誘電体層３，５間に上記AC電圧
が誘起されることになり、従つてZnS発光層４内
に発生した電界によつて伝導帯に励起されかつ加
速されて充分なエネルギーを得た電子が、直接
Mnセンターを励起し、励起されたMn発光セン
ターが基底状態に戻る際に黄橙色の発光を行う。
即ち高電界で加速された電子がZnS発光層４中の
発光センターであるZnサイトに入つたMn原子の
電子を励起し、基底状態に落ちるとき、ほぼ5850
〓をピークに幅広い波長領域で、強い発光を呈す
る。活性物質としてMn以外に希土類の弗化物を
用いた場合にはこの希土類に特有の緑色その他の
発光色が得られる。 When an AC voltage is applied between the electrodes 2 and 6, the above AC voltage is induced between the dielectric layers 3 and 5 on both sides of the ZnS luminescent layer 4, and therefore the electric field generated within the ZnS luminescent layer 4 Therefore, electrons that are excited and accelerated into the conduction band and have obtained sufficient energy can directly
The Mn center is excited, and when the excited Mn luminescent center returns to the ground state, it emits yellow-orange light.
In other words, when the electrons accelerated by a high electric field excite the electrons of the Mn atoms that have entered the Zn site, which is the luminescent center in the ZnS luminescent layer 4, and fall to the ground state, approximately 5850
It emits strong light in a wide wavelength range with a peak of 0. When a rare earth fluoride other than Mn is used as an active substance, green and other luminescent colors characteristic of this rare earth element can be obtained.
しかしながら、上記構造の薄膜EL素子におい
て、発光層内部の出力光はそのすべてを外部に導
出することは不可能である。即ち、発光層での発
光は等方的であるが、このうちの大部分が外部に
取り出される途中の光学的界面における全反射に
より薄膜EL素子内部に閉じ込められる。透明電
極、誘電体層、発光層の屈折率をそれぞれnTE、
nINS、nEMで表し、nEM＞nTE、nINS＞１とすれば、
素子面に対し全反射臨界角θ以上の発光角度をも
つ光子はすべて全反射され、素子内に閉じ込めら
れる。この様子を第２図に示す。ここでθはスネ
ルの法則よりθ＝sin-1１／nEMで与えられる。即ち、
発光層内で立体角4πで放射された光のうち、立
体角4π（１−cosθ）の光のみ外部に取り出され
る、外部発光強度Bpは内部発光強度Biにより次
式で与えられる。 However, in the thin film EL device having the above structure, it is impossible to lead all of the output light inside the light emitting layer to the outside. That is, although the light emitted from the light emitting layer is isotropic, most of the light is trapped inside the thin film EL element by total reflection at the optical interface on the way to being extracted to the outside. The refractive index of the transparent electrode, dielectric layer, and light emitting layer is nTE , respectively.
Expressed by n INS and n EM , if n EM > n TE and n INS > 1, then
All photons with an emission angle greater than or equal to the total reflection critical angle θ with respect to the element surface are totally reflected and confined within the element. This situation is shown in FIG. Here, θ is given by θ=sin -1 1/n EM from Snell's law. That is, of the light emitted at a solid angle of 4π within the light-emitting layer, only the light at a solid angle of 4π (1-cosθ) is extracted to the outside.The external emission intensity B p is given by the internal emission intensity B i by the following equation. .
Bp＝4π（１−cosθ）／4π・Bi ……(1)
たとえばnEM＝2.3（ZnSに相当）とすれば、内部
発光の90％が外部に導出されなくなり、内部に閉
じ込められる。 B p =4π(1−cosθ)/4π·B i (1) For example, if n EM =2.3 (corresponding to ZnS), 90% of the internal light emission will not be led to the outside and will be confined inside.
本発明は上記問題点に鑑み、(1)式が成立しない
薄膜発光素子の構造を確立し、内部発光効率でな
く外部発光効率を高めた新規有用な薄膜EL素子
を提供することを目的とするものである。 In view of the above problems, it is an object of the present invention to establish a structure of a thin film light emitting device in which equation (1) does not hold, and to provide a new and useful thin film EL device that has enhanced external light emitting efficiency rather than internal light emitting efficiency. It is something.
以下、本発明を実施例に従つて図面を参照しな
がら詳説する。 Hereinafter, the present invention will be explained in detail according to embodiments with reference to the drawings.
第３図は本発明の１実施例を説明する薄膜EL
素子の要部構成説明図である。 FIG. 3 is a thin film EL illustrating one embodiment of the present invention.
FIG. 2 is an explanatory diagram of the main part configuration of the element.
同図に示す如く、透明電極２、誘電体層３，
５、発光層４の少なくとも１層において可視光の
散乱構造となるような粒界を形成し、(1)式が成立
しない構造とする。第３図は発光層４内に散乱粒
界８を形成した例である。発光層４内の発光セン
ターで発生した光は発光層４内の散乱粒界８で多
方向性となり、全反射されない方向へ進行した光
が外部へ導出される。 As shown in the figure, a transparent electrode 2, a dielectric layer 3,
5. In at least one layer of the light-emitting layer 4, grain boundaries are formed so as to form a visible light scattering structure, so that the structure does not satisfy equation (1). FIG. 3 shows an example in which scattering grain boundaries 8 are formed within the light emitting layer 4. The light generated at the light emitting center in the light emitting layer 4 becomes multidirectional at the scattering grain boundary 8 in the light emitting layer 4, and the light traveling in a direction that is not totally reflected is guided to the outside.
(1)式の成立しない素子構造においては、全反射
臨界角θ以上の放射角度をもつ光も素子内で乱反
射により全反射臨界角θより小さい放射角度をも
つた成分が生成されて外部へ取り出される。 In an element structure in which equation (1) does not hold, even light with a radiation angle greater than the critical angle of total reflection θ will be diffused within the element, producing a component with a radiation angle smaller than the critical angle of total reflection θ, which will be extracted to the outside. It will be done.
以上より(1)式の代わりに次式が成立する。 From the above, the following equation holds true instead of equation (1).
Bp＞4π（１−cosθ）／4π・Bi
本発明による素子は外部光の入射に対しても散
乱が生じるため、いわゆる白濁を示す。 B p >4π(1−cosθ)/4π·B i The element according to the present invention exhibits so-called cloudiness because scattering occurs even when external light is incident.
発光層４内の散乱粒界８は蒸着工程で蒸着材料
を部分的に分割形成することにより、その分割境
界面を散乱粒界８とする方法等により形成され
る。 The scattering grain boundaries 8 in the light-emitting layer 4 are formed by partially dividing the vapor deposition material in a vapor deposition process and using the dividing boundary surfaces as the scattering grain boundaries 8.
さらに詳しくは、誘電体層５上全面に発光層４
を形成し、周知のホトリングラフイ技術に発光層
４を部分的に除去し、誘電体層５を露出させる。
このピツチを可視光の波長以下にすると、白濁を
おこさせるような散乱を得ることができる。次に
発光層４が部分的に除去された誘電体層５上全面
に、上記発光層４と同じ材料で再度発光層膜を形
成する。この時、再度形成された発光層膜表面に
は、下方の誘電体層５露出面および残置された発
光層４とで形成される凹凸が転写される。続いて
ホトリソグラフイ技術により、上記発光層４上の
発光層膜を選択的に除去して、発光層４表面と誘
電体層５露出面上の発光層膜表面とを略々面一に
する。引き続いてこの発光層４及び発光層膜上に
誘電体層３等を形成して薄膜EL素子を形成する。 More specifically, the light emitting layer 4 is completely covered with the dielectric layer 5.
is formed, and the light emitting layer 4 is partially removed using a well-known photolithography technique to expose the dielectric layer 5.
If this pitch is set to less than the wavelength of visible light, scattering that causes clouding can be obtained. Next, a light emitting layer film is again formed using the same material as the light emitting layer 4 on the entire surface of the dielectric layer 5 from which the light emitting layer 4 has been partially removed. At this time, the unevenness formed by the exposed surface of the lower dielectric layer 5 and the remaining light emitting layer 4 is transferred to the surface of the light emitting layer formed again. Subsequently, the light emitting layer film on the light emitting layer 4 is selectively removed using photolithography technology, so that the surface of the light emitting layer 4 and the surface of the light emitting layer film on the exposed surface of the dielectric layer 5 are approximately flush with each other. . Subsequently, a dielectric layer 3 and the like are formed on the light emitting layer 4 and the light emitting layer film to form a thin film EL element.
第４図は印加電圧対発光輝度（Ｂ−Ｖ）特性を
示すグラフである。図中の曲線l1は上記実施例の
素子であり、l2は鏡面反射を主とする従来の素子
である。曲線l1で明らかな如く上記実施例の薄膜
EL素子は発光輝度の著しい増加が達成されてい
る。 FIG. 4 is a graph showing applied voltage vs. luminance brightness (B-V) characteristics. The curve l1 in the figure is the element of the above embodiment, and the curve l2 is a conventional element that mainly uses specular reflection. As evident from curve l1 , the thin film of the above example
EL devices have achieved significant increases in luminance.
以上詳説した如く、本発明によれば出力光の散
乱反射構造を素子内部に形成することにより、外
部発光効率を著しく増加することができる。 As described in detail above, according to the present invention, by forming a scattering/reflection structure for output light inside the element, external light emission efficiency can be significantly increased.
第１図は薄膜EL素子の基本的構造を示す構成
図である。第２図は出力光の進行過程を示す説明
図である。第３図は本発明の１実施例を説明する
薄膜EL素子の要部構成説明図である。第４図は
印加電圧対発光輝度特性を示す特性図である。
１……ガラス基板、２……透明電極、３，５…
…透電体層、４……発光層、６……背面電極、８
……散乱粒界。
FIG. 1 is a block diagram showing the basic structure of a thin film EL element. FIG. 2 is an explanatory diagram showing the progress process of output light. FIG. 3 is an explanatory diagram of the main part configuration of a thin film EL element explaining one embodiment of the present invention. FIG. 4 is a characteristic diagram showing applied voltage versus luminance luminance characteristics. 1... Glass substrate, 2... Transparent electrode, 3, 5...
...Electroconductor layer, 4...Light emitting layer, 6...Back electrode, 8
...Scattered grain boundaries.
Claims (1)
有する薄膜構造部を１対の電極２，６間に介設し
て成る薄膜EL素子に於いて、前記薄膜構造部は、
前記発光層４に形成された分割境界から成るEL
発光の多方向散乱放射用粒界８を具備して成るこ
とを特徴とする薄膜EL素子。1. In a thin film EL element in which a thin film structure having a light emitting layer 4 that emits EL light upon application of a voltage is interposed between a pair of electrodes 2 and 6, the thin film structure is
EL consisting of dividing boundaries formed in the light emitting layer 4
1. A thin film EL device comprising grain boundaries 8 for multidirectional scattering of emitted light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57114473A JPS595595A (en) | 1982-06-30 | 1982-06-30 | Thin film el element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57114473A JPS595595A (en) | 1982-06-30 | 1982-06-30 | Thin film el element |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2334695A Division JPH03225791A (en) | 1990-11-29 | 1990-11-29 | Thin film electroluminescence (el) element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS595595A JPS595595A (en) | 1984-01-12 |
| JPH0318320B2 true JPH0318320B2 (en) | 1991-03-12 |
Family
ID=14638609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57114473A Granted JPS595595A (en) | 1982-06-30 | 1982-06-30 | Thin film el element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS595595A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW527848B (en) * | 2000-10-25 | 2003-04-11 | Matsushita Electric Ind Co Ltd | Light-emitting element and display device and lighting device utilizing thereof |
| CN100457443C (en) | 2004-05-26 | 2009-02-04 | 日产化学工业株式会社 | Planar luminous body |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49130193A (en) * | 1973-04-11 | 1974-12-13 | ||
| JPS5214395A (en) * | 1975-07-22 | 1977-02-03 | Phosphor Prod Co Ltd | Electroluminescent device |
| JPS5743391A (en) * | 1980-08-26 | 1982-03-11 | Fujitsu Ltd | Method of producing el display element |
-
1982
- 1982-06-30 JP JP57114473A patent/JPS595595A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49130193A (en) * | 1973-04-11 | 1974-12-13 | ||
| JPS5214395A (en) * | 1975-07-22 | 1977-02-03 | Phosphor Prod Co Ltd | Electroluminescent device |
| JPS5743391A (en) * | 1980-08-26 | 1982-03-11 | Fujitsu Ltd | Method of producing el display element |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS595595A (en) | 1984-01-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH0766856B2 (en) | Thin film EL device | |
| JPS6240836B2 (en) | ||
| RU2528321C2 (en) | Transparent organic light-emitting device with high intensity | |
| CA1260592A (en) | Electroluminescent device | |
| JPH06151061A (en) | Electroluminescent element | |
| JPH0318320B2 (en) | ||
| KR101057349B1 (en) | White light source with enhanced brightness | |
| EP1553153A2 (en) | Electroluminescent cell and electroluminescent particle | |
| JPH03225791A (en) | Thin film electroluminescence (el) element | |
| JPH0428197A (en) | End-face radiating type electroluminescent element and its driving method | |
| JPS5827506B2 (en) | Blackened electrode structure | |
| JPH05299175A (en) | El luminescence element | |
| JPS5835587A (en) | Thin film el element | |
| RU222376U1 (en) | Thin Film Electroluminescent Display | |
| JPH0123917B2 (en) | ||
| JPS6323640B2 (en) | ||
| JPH07122366A (en) | Blue emission el element | |
| KR950000156Y1 (en) | El display device | |
| JPH03141586A (en) | Electroluminescent element | |
| JPS629995B2 (en) | ||
| KR970004496B1 (en) | A method for manufacture for electric luminecence device | |
| JPS5855636B2 (en) | Thin film EL element | |
| JPH0773971A (en) | El element | |
| JPS6262437B2 (en) | ||
| KR860002206B1 (en) | El display device |