JPH06124783A - Distributed type el element - Google Patents
Distributed type el elementInfo
- Publication number
- JPH06124783A JPH06124783A JP4271752A JP27175292A JPH06124783A JP H06124783 A JPH06124783 A JP H06124783A JP 4271752 A JP4271752 A JP 4271752A JP 27175292 A JP27175292 A JP 27175292A JP H06124783 A JPH06124783 A JP H06124783A
- Authority
- JP
- Japan
- Prior art keywords
- phosphor
- light emitting
- emitting layer
- high dielectric
- granular
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、分散型ＥＬ（エレクト
ロルミネッセンス）素子に関し、さらに詳しくは、粒状
蛍光体を相対的に粒径の大きい粒状高誘電体の表面に付
着した複合構造の蛍光体を発光層に含有し、十分に向上
された輝度を有する分散型ＥＬ素子に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersion type EL (electroluminescence) device, and more particularly, to a composite phosphor having a granular phosphor adhered to the surface of a granular high dielectric material having a relatively large particle size. The present invention relates to a dispersion-type EL device having a light emitting layer containing, and having sufficiently improved brightness.
【０００２】[0002]
【従来の技術】一般に分散型ＥＬ素子は、図１にその断
面を示すように、透明導電性電極１とアルミニウム箔の
背面電極５の間に、バインダーである高誘電樹脂中に蛍
光体を分散させた発光層３と高誘電樹脂中にチタン酸バ
リウムなどの粒状高誘電体を分散させた絶縁層４とから
構成されている。外側は防湿樹脂２で覆われており、透
明導電性電極と背面電極間に電圧を加えると発光層中の
蛍光体が発光する。2. Description of the Related Art Generally, in a dispersion type EL element, a phosphor is dispersed in a high dielectric resin as a binder between a transparent conductive electrode 1 and a back electrode 5 of aluminum foil, as shown in FIG. The light emitting layer 3 and the insulating layer 4 in which a granular high dielectric material such as barium titanate is dispersed in a high dielectric resin. The outer side is covered with the moisture-proof resin 2, and when a voltage is applied between the transparent conductive electrode and the back electrode, the phosphor in the light emitting layer emits light.
【０００３】このような分散型ＥＬ素子において、輝度
を向上させるために、発光層中の蛍光体にかかる電界を
大きくする工夫がなされている。一般に二種類の誘電体
から構成される物質に電圧を印加すると、電界の強さは
高誘電率の誘電体中よりも低誘電率の誘電体中の方が大
きくなる。In such a dispersion type EL element, in order to improve the brightness, an electric field applied to the phosphor in the light emitting layer is increased. In general, when a voltage is applied to a substance composed of two kinds of dielectrics, the strength of the electric field is higher in the low dielectric constant dielectric material than in the high dielectric constant dielectric material.
【０００４】このことを利用し、発光層中の高誘電樹脂
としてより高い誘電率の樹脂を使うことがなされてい
る。高誘電率樹脂としてシアノエチル化セルロースなど
が使用されているが、樹脂の誘電率は一般に無機材料と
比較して低く、シアノエチル化セルロースでも、誘電率
は２０程度である。このため高誘電樹脂中にさらに高誘
電率の物質を混合分散させ、高誘電樹脂の見かけの誘電
率を大きくすることがなされている。この例として、特
公昭３８−２０６５１公報ではチタン酸バリウムなどの
反射性高誘電率無機材料、特公平３−１７１５９１公報
ではＰ−ニトロアニリンなどの非線形光学材料、特公昭
５７−１８９４９６公報ではＰＺＴ（ＰｂＯ・ＺｒＯ・
ＴｉＯ2 混合焼結体）、特開平３−２９７０９２公報で
はバリウムとチタンとジルコニウムの複合酸化物などの
粒状高誘電体をそれぞれ使って行われている。発光層中
に粒状高誘電体を混合分散させる従来方法は、高誘電樹
脂の見かけの誘電率を大きくするのが目的であり、発光
層中での光の反射、吸収による損失を小さくするため一
般に平均粒径１μｍ程度の粒状高誘電体を用いる。この
ため高誘電体の粒径は通常蛍光体（平均粒径３０μｍ程
度）のそれより小さい。また、特公平４−３４８９３公
報に示されているように蛍光体を液状の高誘電樹脂でコ
ーティングし、更にその外面を熱硬化樹脂で覆ってカプ
セル構造とする方法も提案されている。Utilizing this fact, a resin having a higher dielectric constant has been used as the high dielectric resin in the light emitting layer. Although cyanoethylated cellulose and the like are used as the high dielectric constant resin, the dielectric constant of the resin is generally lower than that of the inorganic material, and even cyanoethylated cellulose has a dielectric constant of about 20. For this reason, a substance having a higher dielectric constant is mixed and dispersed in the high dielectric resin to increase the apparent dielectric constant of the high dielectric resin. As examples of this, Japanese Patent Publication No. 38-20651 discloses a reflective high dielectric constant inorganic material such as barium titanate, Japanese Patent Publication No. 3-171591 discloses a non-linear optical material such as P-nitroaniline, and Japanese Patent Publication No. 57-189496 discloses PZT ( PbO / ZrO /
TiO 2 mixed sintered body), and in Japanese Patent Laid-Open No. 3-297092, a granular high dielectric material such as a complex oxide of barium, titanium and zirconium is used. The conventional method of mixing and dispersing the granular high dielectric material in the light emitting layer is to increase the apparent permittivity of the high dielectric resin, and is generally used to reduce the loss due to the reflection and absorption of light in the light emitting layer. A granular high dielectric material having an average particle size of about 1 μm is used. For this reason, the particle size of the high dielectric material is usually smaller than that of the phosphor (average particle size of about 30 μm). Also, as disclosed in Japanese Patent Publication No. 4-34893, a method has been proposed in which a phosphor is coated with a liquid high dielectric resin and the outer surface of the phosphor is covered with a thermosetting resin to form a capsule structure.
【０００５】[0005]
【発明が解決しようとする課題】高誘電樹脂中にさらに
高誘電体を混合分散させる従来の技術においては、バイ
ンダーである高誘電樹脂の見かけの誘電率が大きくなる
ので蛍光体への電界集中のため輝度は向上するが、発光
層の静電容量も増加するため、電流が増加し消費電力も
増加するという欠点がある。このため、特公平３−２９
７０９２公報に示されているように発光効率（ルーメン
／ワット）は従来品とほぼ同等であった。また蛍光体を
高誘電樹脂でコーティングする方法でも輝度の改善は充
分でない。In the conventional technique of further mixing and dispersing a high dielectric material in a high dielectric resin, the apparent dielectric constant of the high dielectric resin, which is a binder, becomes large, so that the concentration of an electric field on the phosphor is reduced. Therefore, the brightness is improved, but the electrostatic capacity of the light emitting layer is also increased, so that there is a drawback that the current is increased and the power consumption is also increased. Therefore, the Japanese Examined Patent Publication 3-29
As shown in Japanese Patent Publication No. 7092, the luminous efficiency (lumen / watt) was almost the same as that of the conventional product. Further, the improvement of brightness is not sufficient even by coating the phosphor with a high dielectric resin.
【０００６】本発明の目的は、電流をほとんど増加させ
ることなく蛍光体への電界集中をおこすことができ、輝
度の高い分散型ＥＬ素子を提供することにある。An object of the present invention is to provide a dispersion type EL element which can concentrate an electric field on a phosphor with almost no increase in current and has high brightness.
【０００７】[0007]
【課題を解決するための手段】本発明者らは、上記問題
に鑑み、鋭意検討を重ねた結果、ＥＬ素子において特定
の複合構造蛍光体を発光層に含有させると、電流をほと
んど増加させることなく蛍光体への電界集中をおこすこ
とができ輝度が向上することを見出し、本発明を完成さ
せるに至った。Means for Solving the Problems The inventors of the present invention have made extensive studies in view of the above problems, and as a result, when a specific composite structure phosphor in an EL element is contained in a light emitting layer, the current is almost increased. It was found that the electric field could be concentrated on the phosphor without any increase and the brightness was improved, and the present invention was completed.
【０００８】すなわち、本発明は、粒状蛍光体をそれよ
り大きな平均粒径を有する粒状高誘電体の表面に付着さ
せた複合構造の蛍光体を、発光層に含有することを特徴
とする分散型ＥＬ素子に関する。That is, the present invention is characterized in that the light emitting layer contains a phosphor having a composite structure in which a granular phosphor is attached to the surface of a granular high dielectric material having an average particle size larger than that of the granular phosphor. Regarding an EL element.
【０００９】本発明における平均粒径は、粉体工学便覧
（日刊工業社刊）の１２〜１３ページに記載されている
顕微鏡による粒度測定の個数平均粒径である。本発明に
おける粒状高誘電体の表面に、粒状蛍光体を付着させた
複合構造を模式的に示せば図２の通りである。本発明に
おける複合構造において、粒状蛍光体は粒状誘電体の表
面積の約３０％以上、さらに好ましくは約７０％以上を
覆うように付着しているのが好ましい。The average particle diameter in the present invention is a number average particle diameter measured by a microscope as described on pages 12 to 13 of Powder Engineering Handbook (published by Nikkan Kogyo Co., Ltd.). The composite structure in which the granular phosphor is attached to the surface of the granular high dielectric material according to the present invention is schematically shown in FIG. In the composite structure of the present invention, it is preferable that the granular phosphor is attached so as to cover about 30% or more, more preferably about 70% or more of the surface area of the granular dielectric.
【００１０】ＥＬ素子の発光層中で、粒状高誘電体の表
面に粒状蛍光体を付着させた複合構造をつくる方法とし
ては、バインダーである高誘電樹脂溶液に粒状蛍光体と
それに比べて平均粒径の大きい粒状高誘電体を混合、分
散させてペーストをつくり、これを常法に従って基材に
塗布して発光層を形成させる方法、粒状蛍光体粒子とそ
れに比べて平均粒径の大きい粒状高誘電体を特公平３−
２５８９２公報または特公平３−２１９５９１公報に記
載されている気中衝撃処理法により処理することによ
り、予め複合構造の蛍光体をつくり、これを用いて発光
層ペーストをつくり、常法により発光層を形成させる方
法等がある。前者の方法では発光層中で複合構造をとる
蛍光体は部分的であるのに対し、後者の方法では発光層
中で複合構造をとる蛍光体の割合が高いので、後者の方
法によれば前者と比較して輝度はさらに増加すると考え
られる。As a method of forming a composite structure in which the granular phosphor is attached to the surface of the granular high dielectric material in the light emitting layer of the EL device, a high dielectric resin solution as a binder is used to form the granular phosphor and the average particle size compared to that. A method of forming a paste by mixing and dispersing a granular high-dielectric material with a large diameter and applying it to a base material according to a conventional method, and a method of forming a light-emitting layer with a granular phosphor particle and a granular height with a larger average particle diameter than that. Fairness of Dielectric 3-
25892 or Japanese Examined Patent Publication No. 3-219591, a phosphor having a composite structure is prepared in advance by treating with an air impact treatment method, and a luminescent layer paste is prepared using the luminescent material. There is a method of forming it. In the former method, the phosphor having a composite structure in the light-emitting layer is partial, whereas in the latter method, the proportion of the phosphor having a composite structure in the light-emitting layer is high. It is considered that the brightness is further increased as compared with.
【００１１】なお、本発明の高誘電体粒子の表面に蛍光
体粒子が付着した複合構造の蛍光体を前述の気中衝撃処
理法により処理することにより予めつくり、これを用い
て発光層ペーストをつくり、常法により発光層を形成さ
せる方法の場合、発光層ペーストをつくるとき、複合構
造の高誘電体粒子と蛍光体粒子の付着が不十分である
と、蛍光体粒子が高誘電体粒子から脱落することがあ
る。これを防止するためには、高誘電体粒子と蛍光体粒
子の間に樹脂などで薄い接着層を設けた複合構造とする
とよい。この薄い接着層を設けた複合構造をつくる方法
としては、まず気中衝撃処理法などにより高誘電体粒子
の表面に薄い樹脂層をつくり、その後再び気中衝撃処理
法などにより樹脂層に蛍光体粒子を付着させる等の方法
がある。高誘電体粒子と蛍光体粒子の間に樹脂などで薄
い接着層を設けた複合構造では、高誘電体粒子と蛍光体
粒子が接着層により強固に固定され、常法により発光層
ペーストをつくるとき、蛍光体粒子が高誘電体粒子から
脱落するのを防止できる。本発明における粒状蛍光体と
粒状高誘電体との複合構造において、前者が後者に付着
する程度は、上記の方法において両者の混合割合を変え
ることによって調節することができる。The phosphor of the present invention having a composite structure in which the phosphor particles are attached to the surface of the high-dielectric particles is prepared in advance by treating it by the above-mentioned air impact treatment method, and using this, a light emitting layer paste is prepared. In the case of the method of forming the light emitting layer by a conventional method, when the light emitting layer paste is prepared, if the adhesion of the high dielectric particles and the phosphor particles of the composite structure is insufficient, the phosphor particles are separated from the high dielectric particles. May fall out. In order to prevent this, it is advisable to use a composite structure in which a thin adhesive layer made of resin or the like is provided between the high dielectric particles and the phosphor particles. As a method of forming a composite structure provided with this thin adhesive layer, first, a thin resin layer is formed on the surface of the high-dielectric-constant particles by an air impact treatment method or the like, and then the resin layer is again made of a phosphor by an air impact treatment method or the like. There are methods such as attaching particles. In the composite structure in which a thin adhesive layer such as resin is provided between the high-dielectric particles and the fluorescent particles, the high-dielectric particles and the fluorescent particles are firmly fixed by the adhesive layer, and when the light-emitting layer paste is prepared by a conventional method. It is possible to prevent the phosphor particles from falling off the high dielectric particles. In the composite structure of the granular phosphor and the granular high dielectric material according to the present invention, the extent to which the former adheres to the latter can be adjusted by changing the mixing ratio of the two in the above method.
【００１２】本発明で使用される蛍光体としては、硫化
亜鉛などの蛍光体にマンガンや銅などの活性剤と塩素や
臭素などの賦活剤をドープした硫化亜鉛系蛍光体が例示
されるが、これに限定されることなく、分散型ＥＬ素子
用蛍光体として使用可能なＩＩ−ＩＶ族元素の化合物な
ら全て使用できる。本発明で使用される粒状蛍光体の平
均粒径はこれに限定されるものではないが通常１〜４０
μｍである。Examples of the phosphor used in the present invention include a zinc sulfide-based phosphor obtained by doping a phosphor such as zinc sulfide with an activator such as manganese or copper and an activator such as chlorine or bromine. Without being limited to this, any compound of the II-IV group element that can be used as the phosphor for the dispersion type EL device can be used. The average particle size of the granular phosphor used in the present invention is not limited to this, but is usually 1 to 40.
μm.
【００１３】また、本発明で使用される高誘電体として
は、誘電率が１００以上程度の金属酸化物が一般的であ
り、二酸化チタン、チタン酸バリウムなどが例示される
が、これ以外にもＰＺＴ（既述）、ＰＬＺＴ（ＰＺＴに
Ｌａを添加したもの）などの鉛系複合酸化物なども使用
できる。本発明で使用される粒状高誘電体の平均粒径は
これに限定されるものではないが通常１０〜２００μｍ
である。このような比較的平均粒径の大きい高誘電体
は、それの小さいものをふるいにかけて得るなど周知の
方法で得ることができる。本発明において用いられる粒
状高誘電体の粒子形状としては、図２に示すような球形
および球形に近いもの以外に、図３に示すような板状の
ものなどどのような形状のものも含まれる。The high dielectric material used in the present invention is generally a metal oxide having a dielectric constant of about 100 or more, and examples thereof include titanium dioxide and barium titanate. Lead-based composite oxides such as PZT (described above) and PLZT (PZT with La added) can also be used. The average particle size of the granular high dielectric material used in the present invention is not limited to this, but is usually 10 to 200 μm.
Is. Such a high-dielectric material having a relatively large average particle diameter can be obtained by a known method such as sieving a small one. As the particle shape of the granular high dielectric material used in the present invention, in addition to the spherical shape and the shape close to the spherical shape as shown in FIG. 2, any shape such as a plate-like shape as shown in FIG. 3 is included. .
【００１４】粒状蛍光体と粒状高誘電体の組み合わせに
おいて、後者は前者に比べて平均粒径の大きいものが使
用される。後者の平均粒径が前者に比べて小さいと、後
述するように蛍光体粒子が高誘電体粒子のまわりを一部
または全部覆うような好ましい構造を均一にとりにく
い。本発明における粒状蛍光体の平均粒径と粒状誘電体
の平均粒径の比は１：２〜１：１０程度が好ましい。ま
た、粒状高誘電体は、その粒度分布において少なくとも
５０ｗｔ％がそれに付着される蛍光体の平均粒径値に比
べて大きい粒径をもつものであることが好ましい。In the combination of the granular phosphor and the granular high dielectric material, the latter has a larger average particle diameter than the former. If the average particle size of the latter is smaller than that of the former, it is difficult to uniformly form a preferable structure in which the phosphor particles partially or entirely cover the high dielectric particles, as described later. The ratio of the average particle size of the granular phosphor to the average particle size of the granular dielectric in the present invention is preferably about 1: 2 to 1:10. Further, it is preferable that at least 50 wt% of the granular high dielectric material has a particle diameter larger than the average particle diameter value of the phosphor attached to it in the particle size distribution.
【００１５】本発明における発光層において、バインダ
ーである高誘電樹脂と蛍光体と高誘電体との使用割合は
１：１：１〜１：５：５の程度が好ましい。本発明の分
散型ＥＬ素子は、発光層を上記の通りとする以外は、図
１に示したような従来周知の構成とすることができる。In the light emitting layer according to the present invention, the use ratio of the high dielectric resin as the binder, the phosphor and the high dielectric is preferably about 1: 1 to 1: 5: 5. The dispersion type EL device of the present invention can have a conventionally known structure as shown in FIG. 1 except that the light emitting layer is as described above.
【００１６】発光層中に粒状高誘電体を混合分散させる
従来方法は、高誘電樹脂の見かけの誘電率を大きくする
のが目的であり、発光層中での光の反射、吸収による損
失を小さくするため一般に平均粒径１μｍ程度の粒状高
誘電体を用いる。このため高誘電体の粒径は通常蛍光体
（平均粒径３０μｍ程度）のそれより小さい。このよう
な蛍光体と高誘電体を高誘電樹脂中に混合分散させる
と、蛍光体と高誘電体が均一に分散した構造になるので
はなく、高誘電樹脂中で部分的に蛍光体の周囲に高誘電
体の微粒子が付着した構造もできる。The conventional method of mixing and dispersing a granular high dielectric material in the light emitting layer is to increase the apparent permittivity of the high dielectric resin, and to reduce loss due to reflection and absorption of light in the light emitting layer. Therefore, a granular high dielectric material having an average particle size of about 1 μm is generally used. For this reason, the particle size of the high dielectric material is usually smaller than that of the phosphor (average particle size of about 30 μm). When such a phosphor and a high-dielectric material are mixed and dispersed in a high-dielectric resin, a structure in which the phosphor and the high-dielectric material are evenly dispersed is not formed, but the phosphor is partially surrounded by the high-dielectric resin. It is also possible to have a structure in which high dielectric fine particles are attached to.
【００１７】発光層中に高誘電体粒子が存在しないと、
発光層中の電界分布はほぼ一様で、発光層中のどの部分
でも電界強度はほぼ同じとなる。一方、発光層中に高誘
電体粒子が存在すると高誘電体粒子の周辺の電界分布が
変化し、電界強度の大きい部分と小さい部分とが高誘電
体粒子の周辺に現れる。本発明者らは、この電界強度の
変化の大きさと範囲を、電磁界解析シミュレーションソ
フトを使ってコンピュータで計算し推定した。平均粒径
３０μｍ程度の粒状蛍光体の周囲に粒状高誘電体（平均
粒径１μｍ程度）が付着した構造の電磁界解析シミュレ
ーションを行った結果、このケースのように蛍光体の粒
径と比べて高誘電体の粒径が小さい場合は、高誘電体粒
子の周辺の電界分布はあまり変化せず蛍光体の電界はほ
とんど変化しないということがわかった。このように発
光層中に高誘電体を混合分散させる従来方法は、前述の
ように高誘電樹脂の見かけの誘電率を大きくすることは
できるが、上記のように高誘電体粒子周辺の電界分布を
変化させて蛍光体の電界強度を大きくするという目的に
は不十分なものである。また、蛍光体を高誘電体で完全
に被覆した場合についても、電磁界解析シミュレーショ
ンを行ったが、蛍光体の電界強度はコーティング前のそ
れより小さくなった。If high dielectric particles are not present in the light emitting layer,
The electric field distribution in the light emitting layer is almost uniform, and the electric field strength is almost the same in any part of the light emitting layer. On the other hand, when the high-dielectric particles are present in the light emitting layer, the electric field distribution around the high-dielectric particles changes, and a portion having a high electric field strength and a portion having a low electric field strength appear around the high-dielectric particles. The present inventors calculated and estimated the magnitude and range of the change in the electric field strength with a computer using electromagnetic field analysis simulation software. As a result of conducting an electromagnetic field analysis simulation of a structure in which a granular high dielectric material (average particle size of about 1 μm) is attached around a granular phosphor having an average particle size of about 30 μm, it is compared with the particle size of the phosphor as in this case. It was found that when the particle size of the high dielectric material is small, the electric field distribution around the high dielectric particle does not change so much and the electric field of the phosphor hardly changes. As described above, the conventional method of mixing and dispersing the high dielectric material in the light emitting layer can increase the apparent dielectric constant of the high dielectric resin as described above, but as described above, the electric field distribution around the high dielectric particles is high. Is not sufficient for the purpose of increasing the electric field strength of the phosphor by changing. Also, when the phosphor was completely covered with a high dielectric material, an electromagnetic field analysis simulation was performed, and the electric field strength of the phosphor was smaller than that before coating.
【００１８】本発明の分散型ＥＬ素子の発光層における
高誘電体は、発光層中の電界を高誘電体の周辺に限って
局部的に変化させ、高誘電体の周囲に電界強度の大きな
部分を作り出すために使用されている。本発明のような
複合構造にすると高誘電体の周囲の電界強度の大きい部
分に効果的に蛍光体が位置することになり、このため蛍
光体の電界強度が大きくなり、本発明のＥＬ素子の輝度
は向上する。前述した通り、従来の発光層中に高誘電体
を混合分散させる方法によるものでは、使用される高誘
電体の平均粒径が蛍光体に比べ小さいため、発光層中の
高誘電樹脂の見かけの誘電率を高めることはできるが、
高誘電体粒子周辺の電界分布を乱して蛍光体の電界強度
を大きくすることはできない。The high dielectric material in the light emitting layer of the dispersion type EL device of the present invention locally changes the electric field in the light emitting layer only around the high dielectric material, and a portion having a large electric field strength around the high dielectric material. Is used to produce. When the composite structure according to the present invention is used, the fluorescent substance is effectively positioned in a portion having a high electric field intensity around the high dielectric substance, and therefore, the electric field intensity of the fluorescent substance is increased and the EL element of the present invention is The brightness is improved. As described above, according to the conventional method of mixing and dispersing the high dielectric material in the light emitting layer, since the average particle diameter of the high dielectric material used is smaller than that of the phosphor, the appearance of the high dielectric resin in the light emitting layer is Although it is possible to increase the dielectric constant,
It is impossible to increase the electric field strength of the phosphor by disturbing the electric field distribution around the high dielectric particles.
【００１９】高誘電体の平均粒径を蛍光体のそれよりず
っと小さい従来のものから蛍光体のそれにいくらか近づ
けたものを使用すると、発光層中の高誘電樹脂の見かけ
の誘電率を高めると同時に、発光層中に粒状蛍光体の表
面に粒状高誘電体が付着している複合構造ができ、高誘
電体粒子周辺の電界分布が変化し、蛍光体の電界強度が
大きくなる。しかし、このような粒状蛍光体の表面にそ
れより粒径の小さい高誘電体が付着している複合構造で
は、蛍光体粒子のまわりを高誘電体粒子が覆うような構
造になり、蛍光体から生じた光の一部が高誘電体で反射
あるいは吸収されロスを生じることが避けられず、ＥＬ
素子の輝度の向上は十分でない。本発明における複合構
造では、蛍光体粒子が高誘電体粒子のまわりを一部また
は全部覆うような構造になっているので、上記の複合構
造と比べて、高誘電体での反射あるいは吸収によるロス
が少ないと考えられる。The use of a conventional high dielectric material having an average particle diameter much smaller than that of the phosphor from a conventional one, which is somewhat closer to that of the phosphor, increases the apparent dielectric constant of the high dielectric resin in the light emitting layer and at the same time. The composite structure in which the granular high dielectric material is attached to the surface of the granular phosphor is formed in the light emitting layer, the electric field distribution around the high dielectric particle is changed, and the electric field strength of the phosphor is increased. However, in a composite structure in which a high-dielectric material having a smaller particle size is attached to the surface of such a granular phosphor, the high-dielectric particles surround the phosphor particles, and It is inevitable that some of the generated light will be reflected or absorbed by the high-dielectric material, resulting in loss.
The brightness of the device is not sufficiently improved. In the composite structure of the present invention, the phosphor particles are structured so as to partially or entirely cover the periphery of the high-dielectric particles, so that the loss due to reflection or absorption in the high-dielectric material is higher than that of the composite structure. Is considered to be small.
【００２０】本発明において、発光層中の粒状高誘電体
の量は従来の発光層中に高誘電体を混合分散させる方法
によるものと比較し、極く小量で済み、発光層の静電容
量の増加も少ないので、電流の増加が少なく、消費電力
増加も少ない。In the present invention, the amount of the granular high dielectric material in the light emitting layer is extremely small as compared with the conventional method in which the high dielectric material is mixed and dispersed in the light emitting layer. Since the increase in capacity is small, the increase in current is small and the increase in power consumption is small.
【００２１】[0021]
【実施例】以下に本発明の実施例を示すが、本発明はこ
れに限定されるものではない。 実施例１および比較例１ 粒状高誘電体としてチタン酸バリウムは焼結体を粉砕
し、ふるいで分級したもので、平均粒径約１００μｍ
（粒子形状：平均厚み約３０μｍの板状）、誘電率約４
０００のものを使用した。一方、溶剤のジメチルホルム
アミドにシアノエチル化セルロース系高誘電樹脂を溶解
し、シアノエチル化セルロース系高誘電樹脂が２０重量
％である溶液を作成した。この溶液５０ｇに平均粒径約
３０μｍの分散型ＥＬ素子用蛍光体（硫化亜鉛系）１０
ｇと上記チタン酸バリウム１０ｇを混合分散し、発光層
ペーストを作成した。次に図４に示されるような発光強
度観察用分散型ＥＬ素子を以下の手順で作成した。イン
ジウムースズ酸化物の透明電極が形成されている厚み約
１００μｍのポリエステルフィルム上にアプリケーター
で発光層ペーストを塗布し、１２０℃で５分間乾燥し半
乾燥の状態とした。EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. Example 1 and Comparative Example 1 Barium titanate as a granular high dielectric material is obtained by crushing a sintered body and classifying it with a sieve. The average particle diameter is about 100 μm.
(Particle shape: plate shape with an average thickness of about 30 μm), dielectric constant of about 4
000 was used. On the other hand, a cyanoethylated cellulose-based high dielectric resin was dissolved in dimethylformamide as a solvent to prepare a solution containing 20% by weight of the cyanoethylated cellulose-based high dielectric resin. Dispersion type EL device phosphor (zinc sulfide-based) 10 having an average particle size of about 30 μm was added to 50 g of this solution.
g and 10 g of the above barium titanate were mixed and dispersed to prepare a light emitting layer paste. Next, a dispersion type EL device for observing emission intensity as shown in FIG. 4 was prepared by the following procedure. The light emitting layer paste was applied with an applicator onto a polyester film having a thickness of about 100 μm on which a transparent electrode of indium oxide was formed, and dried at 120 ° C. for 5 minutes to be in a semi-dried state.
【００２２】半乾燥状態の発光層を形成したポリエステ
ルフィルムに発光層を形成していないポリエステルフィ
ルムを重ね合わせ、１００℃に加熱した二本ロールラミ
ネータ間を通した。その後６０℃で８時間の乾燥をおこ
ない、発光層の厚みが約７０μｍの発光強度観察用分散
型ＥＬ素子を作成した。A polyester film having no light emitting layer formed thereon was superposed on a polyester film having a light emitting layer in a semi-dried state, and was passed between two roll laminators heated to 100 ° C. Then, the dispersion type EL element for emission intensity observation having a thickness of the light emitting layer of about 70 μm was prepared by drying at 60 ° C. for 8 hours.
【００２３】比較例１として、実施例１で使用したもの
と同じ原料蛍光体を分散型ＥＬ素子用蛍光体とし、発光
強度観察用分散型ＥＬ素子は、実施例１と同様に作成し
た。As Comparative Example 1, the same raw material phosphor as that used in Example 1 was used as a phosphor for a dispersion type EL element, and a dispersion type EL element for observing emission intensity was prepared in the same manner as in Example 1.
【００２４】実施例１の発光強度観察用分散型ＥＬ素子
の発光層内部構造を光学顕微鏡により観測し、図３に示
されるような複合蛍光体構造が部分的に形成されている
ことを確認した。実施例１および比較例１の各発光強度
観察用分散型ＥＬ素子の透明電極を交流電源に接続し、
１００Ｖ、４００Ｈｚの正弦波電圧を印加し輝度及び電
流の測定を行った。その結果実施例１の分散型ＥＬ素子
では比較例１と比較して、電流は約１．２倍また輝度は
約１．４倍に増加した。The internal structure of the light emitting layer of the dispersion type EL device for observing the emission intensity of Example 1 was observed by an optical microscope, and it was confirmed that the composite phosphor structure as shown in FIG. 3 was partially formed. . The transparent electrodes of the dispersion type EL devices for observing the emission intensity of Example 1 and Comparative Example 1 were connected to an AC power source,
A sine wave voltage of 100 V and 400 Hz was applied and the brightness and current were measured. As a result, in the dispersion type EL device of Example 1, the current increased by about 1.2 times and the brightness increased by about 1.4 times as compared with Comparative Example 1.
【００２５】[0025]
【発明の効果】本発明の分散型ＥＬ素子は、従来品に比
べて電流の増加が小さく、蛍光体への電界集中により輝
度が向上する。電流増加による消費電力の増加が少ない
ので、輝度が向上するだけでなく、発光効率（ルーメン
／ワット）も向上させることができる。EFFECT OF THE INVENTION The dispersion type EL device of the present invention has a smaller increase in current as compared with the conventional product, and the brightness is improved by the electric field concentration on the phosphor. Since the increase in power consumption due to the increase in current is small, not only the brightness is improved, but also the luminous efficiency (lumen / watt) can be improved.
【図１】一般的な分散型ＥＬ素子の断面図である。FIG. 1 is a cross-sectional view of a general dispersion type EL device.
【図２】本発明の分散型ＥＬ素子の発光層における複合
蛍光体の例を示す断面図である。FIG. 2 is a cross-sectional view showing an example of a composite phosphor in a light emitting layer of a dispersion type EL device of the present invention.
【図３】本発明の分散型ＥＬ素子の発光層における複合
蛍光体の別の例を示す断面図である。FIG. 3 is a cross-sectional view showing another example of the composite phosphor in the light emitting layer of the dispersion type EL device of the present invention.
【図４】発光強度観察用分散型ＥＬ素子を示す断面図で
ある。FIG. 4 is a sectional view showing a dispersion type EL device for observing emission intensity.
１．透明導電性電極 ２．防湿樹脂 ３．発光層 ４．絶縁層 ５．背面電極（アルミニウム箔など） ６．蛍光体粒子 ７．高誘電体粒子 ８．ポリエステルフィルム 1. Transparent conductive electrode 2. Moisture-proof resin 3. Light-emitting layer 4. Insulating layer 5. Back electrode (aluminum foil, etc.) 6. Phosphor particles 7. High dielectric particles 8. Polyester film
Claims (1)
する粒状高誘電体の表面に付着した複合構造の蛍光体
を、発光層に含有することを特徴とする分散型エレクト
ロルミネッセンス素子。1. A dispersion type electroluminescence device, wherein a phosphor having a composite structure in which a granular phosphor is adhered to the surface of a granular high dielectric material having a larger average particle diameter is contained in a light emitting layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27175292A JP3250276B2 (en) | 1992-10-09 | 1992-10-09 | Dispersion type EL element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27175292A JP3250276B2 (en) | 1992-10-09 | 1992-10-09 | Dispersion type EL element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06124783A true JPH06124783A (en) | 1994-05-06 |
| JP3250276B2 JP3250276B2 (en) | 2002-01-28 |
Family
ID=17504346
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27175292A Expired - Fee Related JP3250276B2 (en) | 1992-10-09 | 1992-10-09 | Dispersion type EL element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3250276B2 (en) |
-
1992
- 1992-10-09 JP JP27175292A patent/JP3250276B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP3250276B2 (en) | 2002-01-28 |
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