JPH03257790A - Electroluminescence (el) light emitting element - Google Patents
Electroluminescence (el) light emitting elementInfo
- Publication number
- JPH03257790A JPH03257790A JP2056070A JP5607090A JPH03257790A JP H03257790 A JPH03257790 A JP H03257790A JP 2056070 A JP2056070 A JP 2056070A JP 5607090 A JP5607090 A JP 5607090A JP H03257790 A JPH03257790 A JP H03257790A
- Authority
- JP
- Japan
- Prior art keywords
- phosphor
- light emitting
- zns
- light
- moisture
- 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
- 238000005401 electroluminescence Methods 0.000 title description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 61
- 229910052984 zinc sulfide Inorganic materials 0.000 claims abstract description 37
- 229910052802 copper Inorganic materials 0.000 claims abstract description 13
- 229910052794 bromium Inorganic materials 0.000 claims abstract description 11
- 239000005083 Zinc sulfide Substances 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims abstract description 5
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000002245 particle Substances 0.000 claims description 29
- 239000011230 binding agent Substances 0.000 claims description 7
- 238000004020 luminiscence type Methods 0.000 claims description 5
- 239000010949 copper Substances 0.000 description 34
- 230000007423 decrease Effects 0.000 description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 6
- 239000000049 pigment Substances 0.000 description 6
- -1 Cu/Z n5=30 XIO-' Chemical compound 0.000 description 5
- 239000004677 Nylon Substances 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 229920001778 nylon Polymers 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- KXJGSNRAQWDDJT-UHFFFAOYSA-N 1-acetyl-5-bromo-2h-indol-3-one Chemical compound BrC1=CC=C2N(C(=O)C)CC(=O)C2=C1 KXJGSNRAQWDDJT-UHFFFAOYSA-N 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 3
- 229910002113 barium titanate Inorganic materials 0.000 description 3
- 230000008094 contradictory effect Effects 0.000 description 3
- 238000000295 emission spectrum Methods 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 2
- NYZGMENMNUBUFC-UHFFFAOYSA-N P.[S-2].[Zn+2] Chemical compound P.[S-2].[Zn+2] NYZGMENMNUBUFC-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000031700 light absorption Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- 239000012190 activator Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- SWLVFNYSXGMGBS-UHFFFAOYSA-N ammonium bromide Chemical compound [NH4+].[Br-] SWLVFNYSXGMGBS-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 description 1
- UUAGAQFQZIEFAH-UHFFFAOYSA-N chlorotrifluoroethylene Chemical group FC(F)=C(F)Cl UUAGAQFQZIEFAH-UHFFFAOYSA-N 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000002305 electric material Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000002808 molecular sieve Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Electroluminescent Light Sources (AREA)
- Luminescent Compositions (AREA)
Abstract
Description
本発明は硫化亜鉛蛍光体を有するＥＬ発光素子に間する
。The present invention relates to an EL light emitting device having a zinc sulfide phosphor.
最近、液晶デイスプレィ等のバック照明用として、薄く
て取り付けに便利な分散型ＥＬ発光素子が注目されてい
る。
この分散型ＥＬ発光素子は、シアノエチルセルローズ等
の有機バインダーに蛍光体粒子を分散させた発光層と、
シアノエチルセルローズ等の高誘電率誘電体に、チタン
酸バリウム粉末等の白色高誘電率誘電体粉末を混合させ
た反射絶縁層と、ＩＴｏ等の透明電極と、アルミニウム
等の背面電極と、ナイロン等の透明な樹脂フィルムから
なる吸湿層と、これ等吸湿層、透明電極、発光層、反射
絶縁層及び背面電極を気密に包囲する防湿性外皮樹脂フ
ィルムとからなっている。
本発明者等は、従来から分散型ＥＬ発光素子に使用され
ていたＺｎＳ： Ｃｕ、Ｃ誌蛍光体に変わって、ＺｎＳ
： Ｃｕ、Ｂｒ蛍光体を開発した（特間昭５７−１４５
１７４号公報）。この蛍光体を使用したＥＬ発光素子は
、従来のＥＬ発光素子を卓越する、優れた発光輝度と長
寿命特性を実現している。ところで、銅を付活剤とした
硫化亜鉛蛍光体は、Ｃｕの含有量が、ＥＬ発光素子の寿
命、発光輝度、発光色に影響を与え、これ等の特性力）
らＣｕの含有量が特定される。従って、ＺｎＳ：Ｃｕ、
Ｂｒ蛍光体は、ＥＬ発光素子に要求される特性によって
Ｃｕの含有量が特定の範囲に決定される。ところが、こ
のＺｎＳ： Ｃｕ、Ｂｒ蛍光体は、Ｃｕの含有量が増加
するに従って、蛍光体自体のボディーカラーが黒くなる
欠点がある。このことは、蛍光体の発光スペクトルの一
部を、蛍光体自体が吸収して実質的に発光輝度を低下さ
せる要因となる。しカルながら、ボディーカラーを白く
する為にＣｕの含有量を減少すると、寿命特性や発光色
に影響を与え、Ｃｕの含有量、即ち、蛍光体のボディー
カラーを白く出来ない。即ち、ＺｎＳ： Ｃｕ、Ｂｒ蛍
光体に含有されるＣｕは、蛍光体自体の発光輝度を向上
する物性と、蛍光体を黒くして発光スペクトルの一部を
吸収するという相反する物性を有し、発光輝度を高くし
て、光の吸収を少なくするという両方の特性を同時に満
足できない。2. Description of the Related Art Recently, distributed EL light-emitting elements, which are thin and convenient to install, have been attracting attention for use in backlighting devices such as liquid crystal displays. This dispersion type EL light emitting element includes a light emitting layer in which phosphor particles are dispersed in an organic binder such as cyanoethyl cellulose;
A reflective insulating layer made by mixing a white high-permittivity dielectric powder such as barium titanate powder with a high-permittivity dielectric material such as cyanoethyl cellulose, a transparent electrode such as ITo, a back electrode such as aluminum, and a material made of nylon etc. It consists of a moisture absorption layer made of a transparent resin film, and a moisture-proof outer resin film that airtightly surrounds the moisture absorption layer, the transparent electrode, the light emitting layer, the reflective insulating layer, and the back electrode. The present inventors have developed ZnS instead of the ZnS: Cu, C phosphor that has been conventionally used in distributed EL light emitting devices.
: Developed Cu, Br phosphor (Tokuma 1986-145)
Publication No. 174). An EL light emitting device using this phosphor achieves excellent luminance and long life characteristics that surpass those of conventional EL light emitting devices. By the way, in the zinc sulfide phosphor using copper as an activator, the Cu content affects the lifespan, luminance, and color of the EL light emitting element, and these characteristics
The content of Cu is specified. Therefore, ZnS:Cu,
The Cu content of the Br phosphor is determined within a specific range depending on the characteristics required for the EL light emitting device. However, this ZnS:Cu,Br phosphor has a drawback that the body color of the phosphor itself becomes darker as the Cu content increases. This causes the phosphor itself to absorb a part of the emission spectrum of the phosphor, resulting in a substantial reduction in luminance. However, if the Cu content is reduced in order to whiten the body color, it will affect the lifetime characteristics and the luminescent color, and the Cu content, that is, the body color of the phosphor cannot be whitened. That is, the Cu contained in the ZnS: Cu, Br phosphor has contradictory physical properties: it improves the luminance of the phosphor itself, and it darkens the phosphor and absorbs a part of the emission spectrum. It is not possible to simultaneously satisfy both characteristics of increasing luminance and decreasing light absorption.
従って、この発明の目的は、発光層の蛍光体が、発光輝
度が高く、しかも蛍光体自体の光の吸収が少ないという
互いに相反する両特性を実現し、これによって、発光輝
度が高くて、寿命が長いＥＬ発光素子を提供するにある
。Therefore, an object of the present invention is to realize two contradictory characteristics of the phosphor of the light-emitting layer: high luminance and low light absorption of the phosphor itself, thereby achieving high luminance and long life. The purpose of the present invention is to provide a long EL light emitting device.
この発明のＥＬ発光素子は、蛍光体粒子をバインダー中
に分散してなる発光層と、この発光層を挟んで重ね合わ
され、少なくとも一方が透光性である２層の電極層と、
外表面を被覆する防湿フィルムとからなる。
発光層の蛍光体の組成は、一般式、
ＺｎＳ： Ｃｕ、Ｂｒで表され、Ｃｕの硫化亜鉛に対す
る含有量が、
ｌＸｌ０−’≦Ｃｕ ／ Ｚ ｎ Ｓ≦５０Ｘ１０−’
の範囲にあり、
ＣｕとＢｒの含有比率が、
０．６≦Ｃｕ／Ｂｒ≦１．５の範囲ζこあり、更に、蛍
光体粒子の平均粒子径が３〜２０μｍの範囲に特定され
ている。The EL light-emitting device of the present invention comprises: a light-emitting layer formed by dispersing phosphor particles in a binder; and two electrode layers, at least one of which is translucent, stacked on top of each other with the light-emitting layer in between.
It consists of a moisture-proof film covering the outer surface. The composition of the phosphor in the light emitting layer is represented by the general formula: ZnS: Cu, Br, and the content of Cu relative to zinc sulfide is lXl0-'≦Cu/ZnS≦50X10-'
The content ratio of Cu and Br is in the range of 0.6≦Cu/Br≦1.5, and the average particle diameter of the phosphor particles is specified to be in the range of 3 to 20 μm. .
本発明のＥＬ発光素子は、発光層の蛍光体ζこ、ＺｎＳ
： Ｃｕ、Ｂｒ蛍光体が使用され、更ζこ、この蛍光体
は平均粒子径が３〜２０μｍと、１に来のＺｎＳ： Ｃ
ｕ、Ｂｒ蛍光体に比べると相当ζこＩ］＼さい範囲に調
整されている。
この粒子径を使用した本発明のＥＬ発光素子ζよ、第１
図のグラフに示す発光輝度と寿命特性を示す。
この図に於て、曲線Ａは、Ｃｕの付活量力１、硫（ヒ亜
鉛に対して、５０Ｘ１０−’と多く、平均粒子径が３０
．ｃｚｍのＺｎＳ： Ｃｕ、Ｂｒ蛍光体を使用した従来
のＥＬ発光素子の発光特性を示し、曲線Ｂは、Ｃｕの付
活量が１５ＸｌＯ−’とこれより少なく、平均粒子径が
３０μｍのＺｎＳ： Ｃｕ、Ｂｒ蛍光体を使用した従来
のＥＬ発光素子の発光特性を示し、曲線Ｃは、Ｃｕの付
活量が曲線Ａと同様で、平均粒子径が１５μｍのＺｎＳ
： Ｃｕ、Ｂｒ蛍光体を使用した本発明のＥＬ発光素子
の発光特性をボす。
このグラフから明らかなように、本発明のＥＬ発光素子
は、初期の発光輝度が、Ｃｕの含有量が少ないものに匹
敵する優れた発光輝度を有し、しかも、相当量のＣｕを
含有する為、極めて優れた長寿命特性を実現している。
即ち、本発光のＺｎＳ：Ｃｕ、Ｂｒ蛍光体を使用したＥ
Ｌ発光素子は、優れた発光輝度特性に加えて、長寿命特
性を備えるという、従来のＥＬ発光素子に切望されて実
現出来なかった、互いに相反する両方の特性を有し、理
想のＥＬ発光素子を完成している。
但し、このグラフの発光輝度測定には、輝度劣化が早く
起こるように、１００ｖ、２０００Ｈｚの定電圧、定周
波数電源を使用した。The EL light emitting device of the present invention has a light emitting layer made of phosphor ζ, ZnS
: Cu, Br phosphor is used, and this phosphor has an average particle size of 3 to 20 μm, and ZnS: C
It is adjusted to a considerably smaller range than the U,Br phosphor. The EL light emitting device ζ of the present invention using this particle size, the first
The graph in the figure shows the luminance brightness and lifetime characteristics. In this figure, curve A shows an activation amount of Cu of 1, a large amount of sulfur (relative to zinc, 50 x 10-'), and an average particle size of 30
．． Curve B shows the luminescence characteristics of a conventional EL light emitting device using a ZnS:Cu,Br phosphor of czm. , shows the luminescence characteristics of a conventional EL light emitting device using a Br phosphor, and curve C is a ZnS film with the same amount of Cu activation as curve A and an average particle diameter of 15 μm.
: The light emitting characteristics of the EL light emitting device of the present invention using Cu, Br phosphor are affected. As is clear from this graph, the EL light emitting device of the present invention has an excellent initial luminance that is comparable to that of a device with a low Cu content, and furthermore, because it contains a considerable amount of Cu, , has achieved extremely excellent long-life characteristics. That is, E using the main luminescent ZnS:Cu,Br phosphor
In addition to excellent luminance characteristics, L-light emitting devices have long life characteristics, which are contradictory characteristics that conventional EL light-emitting devices have longed for but have not been able to achieve, making them an ideal EL light-emitting device. has been completed. However, to measure the luminance of this graph, a constant voltage, constant frequency power source of 100 V and 2000 Hz was used so that luminance deterioration would occur quickly.
以下、第４図を参照しながら、この発明の一実施例につ
いて説明する。
［実施例１］
この図に示されるＥＬ発光素子は、発光層１と、その背
面に位置する絶縁層２と、これら発光層ｌ及び絶縁層２
を挟持すると共に相対向して配置された一対の電極層３
．４と、これら電極層３．４を包囲して外気を遮断する
ための防湿フィルム５．６と、これら全体を気密に包囲
する防湿外皮フィルム７．８とで構成されている。
発光層１は、等表面法相当平均粒子径（本明細書におい
て単に平均粒子径と記述する）が１５μｍであるＺｎＳ
：Ｃｕ、Ｂｒ緑色発光蛍光体１００重量部が、シアノエ
チルセルローズの有機バインダーに均一に分散されて、
発光の光を反射する絶縁層に塗布乾燥されて、厚さが約
７０μｍの発光層となっている。
発光Ｎｌの最適厚さは、好ましくは、蛍光体粒子が約３
Ｎに重なって塗布される程度に調整される。従って、発
光層１の厚さは、蛍光体粒子径の約３倍程度が最適であ
る。蛍光体粒子に比べて発光Ｎ１が厚過ぎると、電極３
と４の間隔が広くなり、また、発光層１の誘電率も低下
して、電極間の静電容量が減少して発光輝度が低下する
。
緑色発光蛍光体には、硫化亜鉛に対する銅のモル数と、
銅と臭素のモル数比、即ち、Ｃｕ ／ Ｚ ｎ５＝３０
ＸＩＯ−’、Ｃｕ／Ｂｒ＝１．０７の蛍光体が使用され
ている。
絶縁層２は、発光層１の有機バインダー溶液と同様な有
機バインダー溶液に、ＢａＴｉＯ３等の強誘電物質の粉
末を溶解させたものを電極Ｎ４に塗布乾燥して形成され
ている。
絶縁Ｎ２の下面、即ち非蛍光面に位置する電極層４は、
銅やアルミニウム板が使用でき、発光層１の上面である
蛍光面に位置する電極３は、導電性と透光性とを有する
電極、例えは、ポリエステルシートの下面にＩｎ２Ｏ３
、ＳｎＯ２，５ｂ２０３等の透明導電膜が付着されたも
のが使用できる。
電極層３．４には、リート線が接続され、リート線は互
いに絶縁される平面状で、防湿外皮フィルム７．８の間
に気密に挟着されて外部に導かれる。
防湿フィルム５．６は、上下の層が電極層３．４０周縁
で連結されて閉鎖空間を形成し、この閉鎖空間内に、電
極層３．４と発光層１と絶縁層２とが気密に収納されて
いる。この防湿フィルム５．６には、内面をポリエチレ
ンでコーティングするナイロンシートが使用される。上
下のナイロンシートは、電極の周縁で、ポリエチレンが
加熱されてヒートシールされている。この構造によると
、ナイロンシートが簡単かつ確実にヒートシールできる
。
ただ、防湿フィルム５．６にはシリカゲル、活性アルミ
ナ、酸化マグネシウム、モレキュラシーブ、合成上オラ
イド等の吸湿材がバインダーでシート状に形成されたも
のも使用できる。
防湿外皮フィルム７．８は、例えは、その内面をポリエ
チレンでコーティングした三フッ化塩化エチレンフィル
ム等の防湿特性及び透光特性のよい熱可塑性合成樹脂か
ら成っており、防湿フィルム５の周縁部は加熱によって
ヒートシールされている。
このように構成されたＥＬ発光素子では、外部交流電源
から引き出し線を介して電極層３．４に交流電界を印加
すると、発光Ｎ１の蛍光体が電界発光し、ＺｎＳ： Ｃ
ｕ、Ｂｒ蛍光体と、赤色蛍光顔料とてだいだい色に発光
し、第１図の表に示すように、初輝度が７４ラドルツク
ス、発光輝度が半減する寿命は、２０００時間と著しく
長寿命のＥＬ発光素子となった。
発光層に使用されているＺｎＳ： Ｃｕ、Ｂｒ蛍光体は
、次の工程で試作する。
ＺｎＳ粉末８００ｇに対し、Ｃｕ （ＣＨ３ＣＯＯ）２
・Ｈ２Ｃを１０ｇ、ＮＨ４Ｂｒを２０ｇ添加して混合す
る。これを乾燥した後、温度９００℃で６時間焼成する
。冷却後湿式粉砕し、充分水洗してろ過乾燥する。得ら
れた蛍光体は、分析の結果、硫化亜鉛に対し、銅のモル
比は３０Ｘ１０−４、臭素のモル比は２８Ｘ１０−’で
あった。
［実施例２〜１０］
発光層に使用されるＺｎＳ： Ｃｕ、Ｂｒ蛍光体の平均
粒子径を、３〜２０μｍの範囲で変化させる以外、実施
例１と同様にして、実施例２〜ＩＯのＥＬ発光素子を試
作した。
［従来例］
発光層に、平均粒子径が３０μｍのＺｎＳ： Ｃｕ、Ｂ
ｒ蛍光体を使用する以外、実施例１と同様にして従来の
ＥＬ発光素子を試作した。
実施例１〜１０および従来例で試作されたＥＬ発光素子
の発光輝度は、第２図の図表に示されている。この図表
に示されるように、ＺｎＳ：Ｃｕ、Ｂｒ蛍光体の平均粒
子径が、３〜２０μｍの範囲にある本発明のＥＬ発光素
子は、従来のＥＬ発光素子に比べると、４〜７％も発光
輝度が向上する。
第３図に、ＺｎＳ： Ｃｕ、Ｂｒ蛍光体の平均粒子径に
対するＥＬ発光素子の初期の相対発光輝度を示す。この
グラフに示されるように、本発明のＥＬ発光素子は、Ｚ
ｎＳ： Ｃｕ、Ｂｒ蛍光体の粒子径が大きくなると、蛍
光体のボディーカラーが濃くなって発光輝度が低下し、
反対に、蛍光体粒子径が小さ過ぎると、蛍光体自体の発
光輝度が低下する。従って、ＺｎＳ： Ｃｕ、Ｂｒ蛍光
体の平均粒子径は、通常３〜２０μｍ５ 好ましくは、
５〜１５μｍの範囲に特定される。
ところで、本発明のＥＬ発光素子の発光層に使用されて
いる、ＺｎＳ： Ｃｕ、Ｂｒ蛍光体は、前にも述べたよ
うに、ＣｕとＢｒの混合率で、発光色と、発光輝度と、
寿命が変化する。ＣｕとＢｒの含有率が高くなると、発
光色が緑色に近付き、減少すると、青色に近付く。また
、銅の混合率は多すぎても、あるいは、少なすぎても発
光輝度は低下する。
従って、ＣｕとＢｒの含有率は、ＥＬ発光素子に要求さ
れる発光色と発光輝度とを考慮して、通常Ｉ Ｘ １０
−’≦Ｃｕ／ＺｎＳ≦５０Ｘ１０−’、好ましくは、２
Ｘ１０−’≦Ｃｕ ／ Ｚ ｎ Ｓ≦５０Ｘ ｌｏ−４
の範囲に調整される。
ところで、ＣｕとＢｒとは、亜鉛の一部に置換されるが
、Ｃｕが＋１価、亜鉛が＋２価、Ｂｒが＋３価であるの
で、Ｚｎ＋２の亜鉛がＣｕ”に置換されると、電子価が
１価不足するので、この不足をＢｒ”が補足する形で置
換される。従って、ＣＵとＢｒのモル量はほぼ等しく、
０．６≦Ｃｕ／Ｂｒ≦１．５の範囲に調整される。
絶縁層２には、前記の材質に限らず、例えはＹ２Ｏ３、
ＴｉＯ２、ＡＱ２０３、ＺｎＯ，ＢａＴｉＯ３、ＰｂＴ
ｉＯ３，５ｒＴｉＣｈ等の強調電体を、単一で、あるい
は複数種混合して高誘電率有機樹脂に分散させたものが
使用できる。
また、以上のＥＬ発光素子は、発光層に顔料粒子を混合
することなく、蛍光体の発光色で発光させているが、こ
の発明は、この発光層に蛍光顔料を混合して、発光色を
蛍光体の発光色と異なる色にすることも可能である。
発光に混合される顔料粒子は、ＺｎＳ：Ｃｕ、Ｂｒ蛍光
体の発光スペクトルを吸収して、これと異なる色に発光
する全てのものが使用できる。
この場合、ＺｎＳ： Ｃｕ、Ｂｒ蛍光体に混合される顔
料粒子の混合率は、蛍光体の発光色、ＥＬ発光素子に要
求される発光色、赤色蛍光顔料の色を考慮して最適値に
調整されるが、通常、蛍光体１００重量部に対して、４
〜２０重量部の範囲に調整される。An embodiment of the present invention will be described below with reference to FIG. [Example 1] The EL light emitting device shown in this figure includes a light emitting layer 1, an insulating layer 2 located on the back surface thereof, and a light emitting layer 1 and an insulating layer 2.
A pair of electrode layers 3 sandwiching and facing each other
．． 4, a moisture-proof film 5.6 that surrounds these electrode layers 3.4 to block outside air, and a moisture-proof outer film 7.8 that airtightly surrounds the entire electrode layer 3.4. The light-emitting layer 1 is made of ZnS having an isosurface method equivalent average particle diameter (herein simply referred to as average particle diameter) of 15 μm.
: 100 parts by weight of Cu, Br green light-emitting phosphor is uniformly dispersed in an organic binder of cyanoethyl cellulose,
It is coated on an insulating layer that reflects emitted light and dried to form a light emitting layer with a thickness of approximately 70 μm. The optimum thickness of the luminescent Nl is preferably about 3 phosphor particles.
Adjustment is made so that the coating overlaps with N. Therefore, the optimal thickness of the light-emitting layer 1 is approximately three times the diameter of the phosphor particles. If the luminescence N1 is too thick compared to the phosphor particles, the electrode 3
The distance between and 4 becomes wider, and the dielectric constant of the light-emitting layer 1 also decreases, and the capacitance between the electrodes decreases, resulting in a decrease in luminance. The green-emitting phosphor contains the number of moles of copper to zinc sulfide;
Molar ratio of copper and bromine, i.e. Cu/Z n5=30
XIO-', a phosphor with Cu/Br=1.07 is used. The insulating layer 2 is formed by dissolving powder of a ferroelectric substance such as BaTiO3 in an organic binder solution similar to the organic binder solution of the light emitting layer 1, and applying the solution to the electrode N4 and drying it. The electrode layer 4 located on the lower surface of the insulation N2, that is, on the non-fluorescent surface, is
A copper or aluminum plate can be used, and the electrode 3 located on the phosphor screen which is the upper surface of the light emitting layer 1 is an electrode having conductivity and translucency, for example, an In2O3 plate on the lower surface of a polyester sheet.
, SnO2, 5b203, etc., to which a transparent conductive film is attached can be used. A Riet wire is connected to the electrode layer 3.4, and the Riet wire is insulated from each other, has a planar shape, and is airtightly sandwiched between the moisture-proof outer film 7.8 and guided to the outside. In the moisture-proof film 5.6, the upper and lower layers are connected at the periphery of the electrode layer 3.40 to form a closed space, and within this closed space, the electrode layer 3.4, the light emitting layer 1, and the insulating layer 2 are airtightly arranged. It is stored. This moisture-proof film 5.6 uses a nylon sheet whose inner surface is coated with polyethylene. The upper and lower nylon sheets are heat-sealed with polyethylene at the periphery of the electrode. According to this structure, the nylon sheet can be heat-sealed easily and reliably. However, as the moisture-proof film 5.6, a sheet formed of a moisture-absorbing material such as silica gel, activated alumina, magnesium oxide, molecular sieve, or synthetic olide with a binder can also be used. The moisture-proof outer skin film 7.8 is made of a thermoplastic synthetic resin with good moisture-proof and light-transmitting properties, such as a trifluorochloroethylene film whose inner surface is coated with polyethylene, and the peripheral edge of the moisture-proof film 5 is Heat sealed by heating. In the EL light emitting device configured in this way, when an AC electric field is applied to the electrode layer 3.4 from an external AC power supply via a lead wire, the phosphor of the light emission N1 emits electroluminescence, and ZnS:C
U,Br phosphor and red fluorescent pigment emit light in orange color, and as shown in the table in Figure 1, the initial brightness is 74 rad, and the lifespan at which the luminance is halved is 2000 hours, which is an extremely long-life EL. It became a light emitting element. The ZnS:Cu,Br phosphor used in the light emitting layer will be prototyped in the next step. Cu (CH3COO)2 for 800g of ZnS powder
- Add 10g of H2C and 20g of NH4Br and mix. After drying this, it is fired at a temperature of 900° C. for 6 hours. After cooling, it is wet-pulverized, thoroughly washed with water, filtered and dried. As a result of analysis, the obtained phosphor had a molar ratio of copper to zinc sulfide of 30×10 −4 and a molar ratio of bromine of 28×10 −′. [Examples 2 to 10] ZnS used in the light emitting layer: Examples 2 to IO were carried out in the same manner as in Example 1 except that the average particle diameter of the Cu, Br phosphor was varied in the range of 3 to 20 μm. An EL light emitting device was prototyped. [Conventional example] ZnS with an average particle size of 30 μm in the light emitting layer: Cu, B
A conventional EL light emitting device was prototyped in the same manner as in Example 1 except that the r phosphor was used. The luminance of the EL light-emitting devices prototyped in Examples 1 to 10 and the conventional example is shown in the chart of FIG. As shown in this chart, the EL light emitting device of the present invention, in which the average particle diameter of the ZnS:Cu,Br phosphor is in the range of 3 to 20 μm, is 4 to 7% more efficient than the conventional EL light emitting device. Emission brightness is improved. FIG. 3 shows the initial relative luminance of the EL light emitting device with respect to the average particle diameter of the ZnS:Cu,Br phosphor. As shown in this graph, the EL light emitting device of the present invention has Z
nS: As the particle size of the Cu, Br phosphor increases, the body color of the phosphor becomes darker and the luminance decreases.
On the other hand, if the phosphor particle size is too small, the luminance of the phosphor itself decreases. Therefore, the average particle diameter of the ZnS: Cu, Br phosphor is usually 3 to 20 μm5, preferably
It is specified in the range of 5 to 15 μm. By the way, as mentioned before, the ZnS:Cu,Br phosphor used in the light emitting layer of the EL light emitting device of the present invention has different emission color, emission brightness, and
Lifespan changes. As the content of Cu and Br increases, the emission color approaches green, and as the content decreases, the emission color approaches blue. Further, even if the mixing ratio of copper is too high or too low, the luminance will decrease. Therefore, the content of Cu and Br is usually I x 10 in consideration of the emission color and luminance required for the EL light emitting device.
-'≦Cu/ZnS≦50X10-', preferably 2
X10-'≦Cu/ZnS≦50X lo-4
is adjusted to the range of By the way, Cu and Br are partially substituted for zinc, but since Cu has a valence of +1, zinc has a valence of +2, and Br has a valence of +3, when Zn+2 zinc is replaced with Cu'', the electron valence increases. Since there is a shortage of one valence, Br'' is substituted to supplement this shortage. Therefore, the molar amounts of CU and Br are almost equal,
It is adjusted to a range of 0.6≦Cu/Br≦1.5. The insulating layer 2 is not limited to the above-mentioned materials, for example, Y2O3,
TiO2, AQ203, ZnO, BaTiO3, PbT
It is possible to use a single emphasizing electric material such as iO3, 5rTiCh, etc., or a mixture of two or more kinds dispersed in a high dielectric constant organic resin. Furthermore, the above EL light-emitting device emits light in the color of the phosphor without mixing pigment particles in the light-emitting layer, but in the present invention, a fluorescent pigment is mixed in the light-emitting layer to change the color of the light emitted. It is also possible to use a color different from that of the phosphor. As the pigment particles to be mixed in the light emission, any particles that absorb the emission spectrum of the ZnS:Cu,Br phosphor and emit light in a color different from this can be used. In this case, the mixing ratio of pigment particles mixed into the ZnS: Cu, Br phosphor is adjusted to an optimal value by taking into consideration the emission color of the phosphor, the emission color required for the EL light-emitting element, and the color of the red fluorescent pigment. However, usually 4 parts by weight per 100 parts by weight of the phosphor.
-20 parts by weight.
第１図はＥＬ発光素子の発光特性を示すグラフ、第２図
はＺｎＳ：Ｃｕ、Ｂｒ蛍光体の平均粒子径に対する発光
輝度を示す図表、第３図は蛍光体粒子径に対するＥＬ発
光素子の相対初輝度を示すグラフ、第４図はＥＬ発光素
子の断面図である。
ｌ・・・・発光層、 ２・・・・絶縁層、３・
・・・電極層、 ４・・・・電極層、５・・・
・防湿フィルム、 ６・・・・防湿フィルム、７・・
・・防湿外皮フィルム、
８・・・・防湿外皮フィルム。Figure 1 is a graph showing the luminescence characteristics of an EL light-emitting device, Figure 2 is a chart showing luminance versus average particle diameter of ZnS:Cu,Br phosphor, and Figure 3 is a graph showing the relative luminance of the EL light-emitting element to the particle diameter of the phosphor. The graph showing the initial luminance and FIG. 4 are cross-sectional views of the EL light emitting element. l...Light emitting layer, 2...Insulating layer, 3...
...electrode layer, 4...electrode layer, 5...
・Moisture-proof film, 6... Moisture-proof film, 7...
... Moisture-proof outer skin film, 8... Moisture-proof outer film.
Claims (1)
この発光層を挟んで重ね合わされ、少なくとも一方が透
光性である２層の電極層と、外表面を被覆する防湿フィ
ルムとからなり、発光層の蛍光体の組成が一般式 ＺｎＳ：Ｃｕ、Ｂｒで表され、Ｃｕの硫化亜鉛に対する
含有量が、 １×１０＾−＾４≦Ｃｕ／ＺｎＳ≦５０×１０＾−＾４
の範囲にあり、 ＣｕとＢｒの含有比率が ０．６≦Ｃｕ／Ｂｒ≦１．５の範囲にあり、更に、蛍光
体粒子の平均粒子径が３〜２０μｍの範囲に特定されて
いるＥＬ発光素子。[Claims] A light-emitting layer formed by dispersing phosphor particles in a binder;
It consists of two electrode layers, at least one of which is translucent, and a moisture-proof film that covers the outer surface, which are overlapped with the luminescent layer in between, and the composition of the phosphor in the luminescent layer is of the general formula ZnS:Cu,Br. It is expressed as follows, and the content of Cu to zinc sulfide is 1×10^-^4≦Cu/ZnS≦50×10^-^4
EL luminescence in which the content ratio of Cu and Br is in the range of 0.6≦Cu/Br≦1.5, and the average particle diameter of the phosphor particles is specified in the range of 3 to 20 μm. element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2056070A JPH03257790A (en) | 1990-03-06 | 1990-03-06 | Electroluminescence (el) light emitting element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2056070A JPH03257790A (en) | 1990-03-06 | 1990-03-06 | Electroluminescence (el) light emitting element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03257790A true JPH03257790A (en) | 1991-11-18 |
Family
ID=13016825
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2056070A Pending JPH03257790A (en) | 1990-03-06 | 1990-03-06 | Electroluminescence (el) light emitting element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03257790A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006063317A (en) * | 2004-06-24 | 2006-03-09 | Fuji Photo Film Co Ltd | Electroluminescent phosphor |
| CN107606495A (en) * | 2017-08-31 | 2018-01-19 | 张俭 | Electric capacity electroluminescent cold light source and preparation method thereof |
-
1990
- 1990-03-06 JP JP2056070A patent/JPH03257790A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006063317A (en) * | 2004-06-24 | 2006-03-09 | Fuji Photo Film Co Ltd | Electroluminescent phosphor |
| CN107606495A (en) * | 2017-08-31 | 2018-01-19 | 张俭 | Electric capacity electroluminescent cold light source and preparation method thereof |
| CN107606495B (en) * | 2017-08-31 | 2020-03-10 | 张俭 | Capacitor electroluminescent cold light source and preparation method thereof |
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