JPS6139718B2 - - Google Patents
Info
- Publication number
- JPS6139718B2 JPS6139718B2 JP56121002A JP12100281A JPS6139718B2 JP S6139718 B2 JPS6139718 B2 JP S6139718B2 JP 56121002 A JP56121002 A JP 56121002A JP 12100281 A JP12100281 A JP 12100281A JP S6139718 B2 JPS6139718 B2 JP S6139718B2
- Authority
- JP
- Japan
- Prior art keywords
- aging
- voltage
- thin film
- light
- zns
- 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
Links
- 230000032683 aging Effects 0.000 claims description 39
- 239000010409 thin film Substances 0.000 claims description 27
- 230000005684 electric field Effects 0.000 claims description 7
- 238000010586 diagram Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 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
- 230000002950 deficient Effects 0.000 description 2
- 238000005566 electron beam evaporation Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000004020 luminiscence type Methods 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
- 239000000758 substrate Substances 0.000 description 2
- 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
- 239000003086 colorant Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 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
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003574 free electron Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000005283 ground state Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
Landscapes
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
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素子の物理
的特性及び絶縁耐圧等を安定化するエージング装
置に関するものである。[Detailed Description of the Invention] The present invention utilizes EL (Electro
This invention relates to an aging device that stabilizes the physical characteristics, dielectric strength, etc. of thin film EL elements that emit light (luminescence).
従来、交流動作の薄膜EL素子に関して、発光
層に規則的に高い電界（106V／cm程度）を印加
し、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素子は発光層界面が分
極保持効果を有するため数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。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
側より降圧している過程で、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到つた。 Conventionally, for AC-operated thin-film EL devices, a high electric field (about 10 6 V/cm) is regularly applied to the light-emitting layer to improve dielectric strength, luminous efficiency, operation stability, etc. % Mn (or Cu,
Three-layer structure ZnS:Mn (or ZnSe:Mn) in which a semiconductor light-emitting layer such as ZnS, ZnSe, etc. doped with Al, Br, etc. is sandwiched with a dielectric thin film such as Y 2 O 3 , TiO 2, etc.
EL devices have been developed, and improvements in various light-emitting characteristics have been confirmed. This thin-film EL element has the characteristics of emitting high-intensity light when an alternating current electric field of several KHz is applied because the light-emitting layer interface has a polarization retention effect, and also having a long life. 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 hysteresis characteristics, 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 opened up a new field of application for display technology.
薄膜EL素子の１例としてZnS：Mn薄膜EL素子
の基板的構造を第１図に示す。 As an example of a thin film EL device, the substrate structure of a ZnS:Mn thin film EL device is shown in FIG.
添附図面に基いて薄膜EL素子の構造を具体的
に説明すると、ガラス基板１上に1n2O3，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。ZnS発光層４上に
は第１の誘電体層３と同様の材質から成る第２の
誘電体層５が積層され、更にその上にAl等から
成る背面電極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。 The structure of the thin film EL device will be explained in detail based on the attached drawings. A transparent electrode 2 made of 1n 2 O 3 , SnO 2 , etc. is placed on a glass substrate 1, and Y 2 O 3 , etc. is layered on top of the transparent electrode 2.
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. A second dielectric layer 5 made of the same material 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 thereon. The transparent electrode 2 and the back electrode 6 are connected to an AC power source 7, and the thin film
The EL element is driven.
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より、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、ZnS発
光層４界面へ誘引される過程で直接Mn発光セン
ターを励起し、励起されたMn発光センターが期
底状態に戻る際に黄橙色の発光を行なう。即ち高
電界で加速された自由電子が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、基底状態に落ちる時、略々5850Å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 AC voltage is induced between the dielectric layers 3 and 5 on both sides of the ZnS light emitting layer 4, and the electric field generated within the ZnS light emitting layer 4 causes The electrons that are excited and accelerated into the conduction band and have acquired sufficient energy directly excite the Mn luminescent center in the process of being attracted to the ZnS luminescent layer 4 interface, and the excited Mn luminescent center returns to the bottom state. It emits yellow-orange light. That is, when free electrons accelerated by a high electric field excite the electrons of Mn atoms that enter the Zn site, which is the luminescent center in the ZnS luminescent layer 4, and fall to the ground state, the electrons emit light in a wide wavelength range with a peak of approximately 5850 Å. Exhibits strong luminescence.
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.
上記構造を基本とする薄膜EL素子は、発光輝
度等の経時変化の安定化と初期故障による不良素
子を除去する等の目的で、薄膜作製後一定期間交
流電圧を透明電極２と背面電極６間に印加しなが
らエージングを行なうことが必要となる。エージ
ング時間は従来十数時間から数十時間もの長時間
を必要としていた。エージング処理を効率良く行
なうことにより発光輝度等の物理的特性が安定化
し、初期故障以外の不良素子の発生が抑制され
る。 A thin film EL device based on the above structure is designed to apply an AC voltage between the transparent electrode 2 and the back electrode 6 for a certain period of time after the thin film is fabricated, for the purpose of stabilizing changes in luminance over time and removing defective elements due to initial failure. It is necessary to perform aging while applying Conventionally, the aging time required a long time, ranging from more than ten hours to several tens of hours. By performing the aging process efficiently, physical characteristics such as luminance of light emission are stabilized, and the occurrence of defective elements other than initial failures is suppressed.
薄膜EL素子はエージング過程に於いて、その
発光輝度―印加電圧特性（以下Ｂ―Ｖ特性と称
す）が第２図に示す如く変化することが知られて
いる。従つて、従来の如く一定電圧値のエージン
グ電圧を印加しながら熱処理した場合、時間の経
過に従つてエージング効率が低下するといつた欠
点があつた。エージング効率を低下させることな
く有効な熱処理即ちエージングを短時間に行なう
ためには、Ｂ―Ｖ特性曲線上の動作点をエージン
グ動作中ほぼ一定にすることが必要であり、Ｂ―
Ｖ特性曲線上に動作点を固定する方法として第３
図に示す如く発光開始電圧（輝度１フートランパ
ートを与える電圧）Vthもエージング動作中に変
化するが、このVthの変化に追従してVth＋Vc
（Vcは一定）なる電圧値を有するエージング電圧
を印加する方法が考えられる。従来のエージング
方法では、このVth＋Vcにエージング電圧を近似
させるため、エージング開始後特定時間毎に数回
強制的にエージング電圧を昇圧させるようにして
いた。この場合には実際のエージング電圧は第４
図に実線で示すような階段状の電圧値となる。し
かしながら、この方法ではエージング条件が理想
条件に近似されるだけであり、また条件設定を
度々変更する必要が生じ、多大の労力を浪費する
とともに大量の薄膜EL素子を同時にエージング
処理することは困難であつた。 It is known that the luminance-applied voltage characteristic (hereinafter referred to as BV characteristic) of a thin film EL element changes as shown in FIG. 2 during the aging process. Therefore, when heat treatment is performed while applying an aging voltage of a constant voltage value as in the conventional method, there is a drawback that the aging efficiency decreases as time passes. In order to perform effective heat treatment, that is, aging in a short time without reducing the aging efficiency, it is necessary to keep the operating point on the B-V characteristic curve almost constant during the aging operation.
The third method of fixing the operating point on the V characteristic curve is
As shown in the figure, the emission starting voltage (voltage that gives one foot rampart of brightness) Vth also changes during the aging operation, and Vth+Vc follows this change in Vth.
A method of applying an aging voltage having a voltage value of (Vc is constant) can be considered. In conventional aging methods, in order to approximate the aging voltage to Vth+Vc, the aging voltage is forcibly increased several times at specific time intervals after the start of aging. In this case, the actual aging voltage is
This results in step-like voltage values as shown by the solid line in the figure. However, this method only approximates the aging conditions to ideal conditions, and it is necessary to change the condition settings frequently, which wastes a lot of effort and makes it difficult to age a large number of thin film EL devices at the same time. It was hot.
本発明は上記現状に鑑み、技術的手段を駆使す
ることによりVthの変化に追従して自動的にVth
＋Vcなるエージング電圧を印加することのでき
る新規有用な薄膜EL素子のエージング装置を提
供することを目的とするものである。 In view of the above-mentioned current situation, the present invention makes full use of technical means to automatically adjust Vth by following changes in Vth.
The object of the present invention is to provide a new and useful aging device for thin-film EL devices that can apply an aging voltage of +Vc.
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５図は本発明の１実施例を示すエージング装
置のブロツク回路構成図である。 FIG. 5 is a block circuit diagram of an aging device showing one embodiment of the present invention.
薄膜EL素子の駆動回路に定電流源を接続し、
また駆動回路にはエージング電圧を印加するため
の交流矩形波発生信号回路が連結されている。薄
膜EL素子の発光時のインピーダンスＺはエージ
ング動作中Ｂ―Ｖ特性の変化に対応して変化す
る。従つてこのエージング過程に於けるインピー
ダンス変化をＶ＝Ｉ・｜Ｚ｜（Ｉは電流）より電
圧変化に変換し、エージング電圧をVthの変化に
追従するVth＋Vcに設定することができる。Vc
の値は15ボルトから80ボルト程度の範囲で決定し
望ましくは20ボルトから50ボルトの範囲の値とす
る。 Connect a constant current source to the drive circuit of the thin film EL element,
Further, an AC rectangular wave generation signal circuit for applying an aging voltage is connected to the drive circuit. The impedance Z of the thin film EL element during light emission changes in accordance with the change in the BV characteristics during the aging operation. Therefore, the impedance change in this aging process can be converted into a voltage change from V=I·|Z| (I is current), and the aging voltage can be set to Vth+Vc that follows the change in Vth. Vc
The value of is determined in the range of about 15 volts to 80 volts, preferably in the range of 20 volts to 50 volts.
第６図は第５図の装置により薄膜EL素子に印
加されるエージング電圧の変化を示す説明図であ
る。 FIG. 6 is an explanatory diagram showing changes in the aging voltage applied to the thin film EL element by the apparatus shown in FIG.
以上よりエージング電圧は初期設定するのみで
Vthの変化にほぼ対応して追従しながら昇圧され
ることとなる。 From the above, the aging voltage can only be set initially.
The voltage will be increased while following the change in Vth.
以上詳説した如く本発明によれば駆動回路に定
電流電源を接続した比較的簡単な装置で薄膜EL
素子のVthの変化に連続的に追従したエージング
電圧を自動的に制御しながら印加することがで
き、労力を要することなく効率の良いエージング
処理を行なうことができる。 As explained in detail above, according to the present invention, thin-film EL
The aging voltage that continuously follows the change in Vth of the element can be applied while being automatically controlled, and efficient aging processing can be performed without requiring much effort.
第１図は薄膜EL素子の基本的構成を示す説明
図である。第２図は薄膜EL素子のＢ―Ｖ特性を
示す説明図である。第３図はVthの変化を説明す
る説明図である。第４図は従来のエージング電圧
の変化を示す説明図である。第５図は本発明の１
実施例を示すエージング装置のブロツク回路構成
図である。第６図は第５図のエージング装置によ
つて得られるエージング電圧の変化を示す説明図
である。
２……透明電極、４……ZnS発光層、６……背
面電極、７……交流電源。
FIG. 1 is an explanatory diagram showing the basic structure of a thin film EL element. FIG. 2 is an explanatory diagram showing the BV characteristics of a thin film EL element. FIG. 3 is an explanatory diagram illustrating changes in Vth. FIG. 4 is an explanatory diagram showing a conventional aging voltage change. Figure 5 shows part 1 of the present invention.
1 is a block circuit configuration diagram of an aging device showing an embodiment. FIG. FIG. 6 is an explanatory diagram showing changes in aging voltage obtained by the aging device of FIG. 5. 2...Transparent electrode, 4...ZnS light emitting layer, 6...Back electrode, 7...AC power supply.
Claims (1)
を１対の電極間に介設して成る薄膜EL素子に前
記１対の電極を介してエージング電圧を印加しな
がら熱処理する薄膜EL素子のエージング装置に
於いて、エージング電圧を印加する回路部に定電
流源を接続し、前記薄膜EL素子のエージング中
のインピーダンス変化を電圧変換して前記回路部
でエージング電圧を決定するようにしたことを特
徴とする薄膜EL素子のエージング装置。1. Aging of a thin film EL device in which a thin film EL device is heat-treated while applying an aging voltage via the pair of electrodes to a thin film EL device in which a light emitting layer that emits EL light in response to the application of an electric field is interposed between a pair of electrodes. The device is characterized in that a constant current source is connected to a circuit section that applies an aging voltage, and the aging voltage is determined in the circuit section by converting impedance changes during aging of the thin film EL element into voltage. Aging device for thin film EL devices.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56121002A JPS5823190A (en) | 1981-07-31 | 1981-07-31 | Device for ageing thin film el element |
| US06/401,385 US4818913A (en) | 1981-07-31 | 1982-07-23 | Aging method for thin-film electroluminescent display panel |
| GB08222041A GB2105108B (en) | 1981-07-31 | 1982-07-30 | Aging electroluminescent devices |
| DE3228565A DE3228565C2 (en) | 1981-07-31 | 1982-07-30 | Method for aging a thin-film electroluminescent display element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56121002A JPS5823190A (en) | 1981-07-31 | 1981-07-31 | Device for ageing thin film el element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5823190A JPS5823190A (en) | 1983-02-10 |
| JPS6139718B2 true JPS6139718B2 (en) | 1986-09-05 |
Family
ID=14800345
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56121002A Granted JPS5823190A (en) | 1981-07-31 | 1981-07-31 | Device for ageing thin film el element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5823190A (en) |
-
1981
- 1981-07-31 JP JP56121002A patent/JPS5823190A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5823190A (en) | 1983-02-10 |
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