JPH0249395A - Data writing device of membranous el element - Google Patents
Data writing device of membranous el elementInfo
- Publication number
- JPH0249395A JPH0249395A JP63197834A JP19783488A JPH0249395A JP H0249395 A JPH0249395 A JP H0249395A JP 63197834 A JP63197834 A JP 63197834A JP 19783488 A JP19783488 A JP 19783488A JP H0249395 A JPH0249395 A JP H0249395A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- light
- thin film
- display panel
- writing
- 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
- JGIATAMCQXIDNZ-UHFFFAOYSA-N calcium sulfide Chemical compound [Ca]=S JGIATAMCQXIDNZ-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052693 Europium Inorganic materials 0.000 claims abstract description 8
- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000010409 thin film Substances 0.000 claims description 39
- 230000001678 irradiating effect Effects 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 17
- 229910052581 Si3N4 Inorganic materials 0.000 abstract description 5
- 239000011521 glass Substances 0.000 abstract description 5
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 abstract description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 4
- 229910052782 aluminium Inorganic materials 0.000 abstract description 4
- 230000015556 catabolic process Effects 0.000 abstract description 4
- 238000005268 plasma chemical vapour deposition Methods 0.000 abstract description 4
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 abstract description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 2
- 238000005566 electron beam evaporation Methods 0.000 abstract description 2
- 238000001704 evaporation Methods 0.000 abstract description 2
- 230000008020 evaporation Effects 0.000 abstract description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 abstract description 2
- 229910052814 silicon oxide Inorganic materials 0.000 abstract description 2
- 239000012528 membrane Substances 0.000 abstract 4
- 230000015572 biosynthetic process Effects 0.000 abstract 1
- 238000010438 heat treatment Methods 0.000 abstract 1
- 239000012212 insulator Substances 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 10
- 239000010408 film Substances 0.000 description 7
- 230000006378 damage Effects 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 239000011575 calcium Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 229910052724 xenon Inorganic materials 0.000 description 2
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 2
- 229910052984 zinc sulfide Inorganic materials 0.000 description 2
- 239000005132 Calcium sulfide based phosphorescent agent Substances 0.000 description 1
- 206010034972 Photosensitivity reaction Diseases 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005083 Zinc sulfide Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- CPBQJMYROZQQJC-UHFFFAOYSA-N helium neon Chemical compound [He].[Ne] CPBQJMYROZQQJC-UHFFFAOYSA-N 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000006386 memory function Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000036211 photosensitivity Effects 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Electroluminescent Light Sources (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Control Of El Displays (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、発光輝度の対印加電圧特性においてヒステリ
シス特性を示す薄膜ＥＬ素子の情報書込み装置に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an information writing device for a thin film EL element that exhibits hysteresis characteristics in the characteristics of luminance versus applied voltage.
（従来の技術）
ユーロピウム（Ｅｕ）を添加した硫化カルシウム（Ｃａ
Ｓ） 薄膜を発光層とした赤色発光の薄膜エレクトロル
ミネセンス素子において、第６図に示すように、印加電
圧を昇圧していく過程と印加電圧を高電圧側から降圧し
ていく過程で、同じ印加電圧値に対して異なる発光輝度
を示すという特性、すなわちヒステリシス特性があるこ
とが報告されている（Ｋ、Ｔａｎａｋａ、八、Ｍｉｋａ
ｍｉ、 Ｔ、Ｏｇｕｒａ、 Ｋ、Ｔａｎｉｇｕｃｈｉ。(Conventional technology) Calcium sulfide (Ca) added with europium (Eu)
S) In a red-emitting thin film electroluminescent device with a thin film as a light emitting layer, as shown in Figure 6, the process of increasing the applied voltage and the process of decreasing the applied voltage from the high voltage side are the same. It has been reported that there is a characteristic of exhibiting different luminance brightness depending on the applied voltage value, that is, a hysteresis characteristic (K, Tanaka, Hachi, Mika
mi, T., Ogura, K., Taniguchi.
Ｍ、Ｙｏｓｈｉｄａ、 Ｓ、Ｎａｋａｊｉｍａ＋ １９
８６ Ｊａｐａｎ Ｄｉｓｌａｙ ｐ２４６）。M, Yoshida, S, Nakajima+ 19
86 Japan Display p246).
このような特性を示す薄膜ＥＬ素子は、一般に第５図に
示すように、ユーロピウム（Ｅｕ）を添加した硫化カル
シウム（ＣａＳ）薄膜９、窒化シリコン等の絶縁層１０
．１１、透明電極１２、アルミニウム等の背面電極１３
の薄膜が、ガラス基板１４上に順次積層して形成された
構造となっている。Thin film EL devices exhibiting such characteristics generally include a calcium sulfide (CaS) thin film 9 doped with europium (Eu) and an insulating layer 10 of silicon nitride or the like, as shown in FIG.
．． 11, transparent electrode 12, back electrode 13 made of aluminum, etc.
The structure is such that thin films of are sequentially laminated on a glass substrate 14.
このような構造の素子で、発光層に添加されるＥｕの濃
度と発光層の薄膜を制御することにより、印加電圧に対
する輝度特性に第６図に示すようなヒステリシス特性を
持たせることができる。このヒステリシス特性を利用す
ると、上記ＥＬ素子を一種のメモリー機能素子として動
作させることができ、素子の発光輝度の大小として任意
に情報を書キ込み、メモリーさせることができる。この
素子に情報を書き込む方法としては電気的書込み方式が
一般的に知られている。In an element having such a structure, by controlling the concentration of Eu added to the light-emitting layer and the thin film of the light-emitting layer, the luminance characteristics with respect to the applied voltage can have hysteresis characteristics as shown in FIG. 6. By utilizing this hysteresis characteristic, the EL element can be operated as a type of memory function element, and information can be arbitrarily written and stored in terms of the magnitude of the luminance of the element. An electrical writing method is generally known as a method for writing information into this element.
電気的書込み方式とは、第６図に示すように、電圧上昇
時の最小発光輝度と電圧降下時の最大発光輝度との差が
十分に大きい点の電圧値を振幅とする交流電圧■、を、
維持電圧とし素子に印加した状態では発光輝度が８７で
あり、情報の書き込み時に上記維持電圧よりも振幅の大
きい電圧ｖｗを印加すると、発光輝度がＥ、に達して書
き込みが行われる方式である。As shown in Figure 6, the electrical writing method uses an AC voltage whose amplitude is the voltage value at a point where the difference between the minimum luminance when the voltage rises and the maximum luminance when the voltage drops is sufficiently large. ,
When a sustaining voltage is applied to the element, the luminance is 87, and when a voltage vw with a larger amplitude than the sustaining voltage is applied when writing information, the luminance reaches E and writing is performed.
しかしながら、上記電気的書込み方式によってデータを
書き込み、表示する平面型表示パネルを実現することは
極めて難しく、まだ実用化されるに至っていない。その
理由は、最適な維持電圧値がパネル面上で場所によりば
らつき、このためデータの均一な書き込みが難しいこと
、および書き込みを確実にするため書き込み電圧を上げ
ると絶縁破壊電圧を越える電圧が印加される画素ができ
、部分的に画素が絶縁破壊し、画素欠けが生じ易いため
である。However, it is extremely difficult to realize a flat display panel that writes and displays data using the electrical writing method, and has not yet been put to practical use. The reason for this is that the optimal sustain voltage value varies depending on the location on the panel surface, which makes it difficult to write data uniformly, and that when the write voltage is increased to ensure writing, a voltage that exceeds the dielectric breakdown voltage is applied. This is because the pixel is likely to be partially damaged due to dielectric breakdown, resulting in pixel chipping.
このような動作点のばらつきは、発光層、絶縁層の膜厚
むら、および電極材料の抵抗による電圧降下等によって
生じる。このうち膜厚むらによる動作点のばらつきは、
膜厚むらを零にすることにより原理的には解決可能であ
るが、通常の薄膜形成方法を用いている限り、膜厚むら
を零にすることは不可能である。また、電極抵抗による
電圧降下も本質的に回避不可能であり、この原因による
動作点のばらつきは、素子の面積が大きくなるほど、精
細度を上げるほど大きな問題となってくる。Such variations in the operating point are caused by uneven thicknesses of the light emitting layer and the insulating layer, voltage drops due to resistance of electrode materials, and the like. Among these, the variation in operating point due to film thickness unevenness is
In principle, this problem can be solved by reducing the film thickness unevenness to zero, but as long as a normal thin film forming method is used, it is impossible to reduce the film thickness unevenness to zero. Further, a voltage drop due to electrode resistance is essentially unavoidable, and variations in the operating point due to this cause become a bigger problem as the area of the element becomes larger and the precision becomes higher.
いずれにせよ各画素での動作点のばらつきは不可避であ
り、このため前述したように電気的書込み方式では、書
き込みエラーおよび書き込みによる画素破壊が生じ易い
という欠点があった。In any case, variations in the operating point of each pixel are unavoidable, and therefore, as described above, the electrical writing method has the disadvantage that writing errors and pixel destruction due to writing are likely to occur.
このほか、電気的書込み方式では、維持電圧に書き込み
電圧を重畳させるため、電圧振幅が異なる二種類の電圧
を印加する駆動回路が必要とされるので、回路構成が複
雑になるという欠点があった。In addition, the electrical writing method requires a drive circuit that applies two types of voltages with different voltage amplitudes in order to superimpose the writing voltage on the sustain voltage, which has the disadvantage of complicating the circuit configuration. .
（発明が解決しようとする課題）
本発明は、発光輝度の対印加電圧特性において、ヒステ
リシス特性を示す薄膜ＥＬ素子に、光照射により情報を
書き込み、前記電気的書込み方式の欠点を解決して、書
き込みによる画素破壊等が生じない薄膜ＥＬ素子の情報
書込み装置を提供することにある。(Problems to be Solved by the Invention) The present invention solves the drawbacks of the electrical writing method by writing information by light irradiation on a thin film EL element that exhibits hysteresis characteristics in the luminance versus applied voltage characteristic. An object of the present invention is to provide an information writing device for a thin film EL element that does not cause pixel destruction due to writing.
（課題を解決するための手段）
本発明の装置は、電圧上昇時の最小発光輝度と電圧降下
時の最大発光輝度との差が十分に大きい点の電圧値を振
幅とする交流電圧を、維持電圧として装置に印加してお
き、書き込みが必要な部分に光を照射することにより、
発光層の物性パラメータ（例えば、電気分極率等）を変
化させて書き込みを行うものである。このため印加電圧
を昇圧する必要がな（、電気的書込み方式で問題となっ
た書き込みによる画素の破壊は生じない。また、電気駆
動回路自体は一定の維持電圧を発生するだけでよく、回
路構成が簡単になる。さらに本発明の装置は、上述のう
よに電気的書込み方式の欠点を解決できるのみならず、
それに加えて光が照射された部分の書き込みが行われる
ので、座標検出系を重畳して用いなくとも、単独でデイ
スプレィパネル面に直接、画像情報を入力できる。(Means for Solving the Problems) The device of the present invention maintains an AC voltage whose amplitude is a voltage value at a point where the difference between the minimum luminance when the voltage increases and the maximum luminance when the voltage drops is sufficiently large. By applying a voltage to the device and irradiating light onto the area where writing is required,
Writing is performed by changing the physical parameters (for example, electric polarizability, etc.) of the light emitting layer. Therefore, there is no need to boost the applied voltage (pixel destruction due to writing, which was a problem with the electrical writing method, does not occur.In addition, the electric drive circuit itself only needs to generate a constant maintenance voltage, and the circuit configuration Further, the device of the present invention not only solves the drawbacks of the electrical writing method as described above, but also
In addition, since writing is performed on the portion irradiated with light, image information can be input directly onto the display panel surface without using a superimposed coordinate detection system.
この光照射によって書き込みが可能であることは、われ
われによって初めて発見されたものであり、以下にその
経緯と光書き込み特性について詳細に説明する。We were the first to discover that writing is possible through this light irradiation, and the background and optical writing characteristics will be explained in detail below.
ユーロピウム（Ｅｕ）を添加した硫化カルシウム（Ｃａ
Ｓ） Ｆｊｌ膜を発光層とした薄膜ＥＬ素子にヒステリ
シス特性を持たせるために、発光層の膜厚、発光層に添
加するＥ、の濃度、絶縁層薄膜の材質を、適切に選択す
る必要があることは周知の事実である。われわれは種々
の実験、検討を重ね、良好なヒステリシス特性を実現さ
せるためには、前記条件のほかに、発光層の結晶性が重
要な要素であることを見い出した。この結果に基づいて
硫化カルシウム発光層薄膜の結晶性を改善し、かつ絶縁
層薄膜の膜質（組成、応力、絶縁耐圧等）を最適化する
ことによって、光照射により発光層の電気分極率が変化
する素子を実現した。また、従来の報告ではヒステリシ
ス特性を生せしめるには、発光層膜厚が、１．４μｍ以
上必要とされ、かつヒステリシス特性における昇圧時と
降圧時の閾電圧の差（ヒステリシスマージン）が高々２
０ Ｖであったのに対して、われわれの素子では発光層
の結晶性を改善した結果、発光層膜厚が１μｍであるに
も拘わらずヒステリシスマージンが４０ Ｖにも達する
ものが実現でき、ヒステリシス特性自体も大幅に改善さ
せることができた。Calcium sulfide (Ca) added with europium (Eu)
S) In order to provide hysteresis characteristics to a thin film EL device using an Fjl film as a light emitting layer, it is necessary to appropriately select the thickness of the light emitting layer, the concentration of E added to the light emitting layer, and the material of the thin insulating layer. This is a well-known fact. Through various experiments and studies, we have found that in addition to the above conditions, the crystallinity of the light emitting layer is an important factor in achieving good hysteresis characteristics. Based on this result, by improving the crystallinity of the calcium sulfide light-emitting layer thin film and optimizing the film quality (composition, stress, dielectric strength, etc.) of the insulating layer thin film, the electric polarizability of the light-emitting layer changes upon light irradiation. We have realized a device that does this. In addition, in previous reports, in order to produce hysteresis characteristics, the thickness of the light-emitting layer must be 1.4 μm or more, and the difference in threshold voltage between step-up and step-down (hysteresis margin) in hysteresis characteristics is at most 2.
In contrast, in our device, as a result of improving the crystallinity of the light-emitting layer, we were able to achieve a hysteresis margin of 40 V even though the light-emitting layer thickness was 1 μm. The characteristics themselves were also significantly improved.
第３図に本発明で用いた薄膜ＥＬ素子の光照射による静
電容量変化を示した光容量特性の一例を示す。FIG. 3 shows an example of the photocapacitance characteristic showing the capacitance change due to light irradiation of the thin film EL element used in the present invention.
ここでＣｏは光を照射しないときの静電容量、ΔＣは光
を照射したときの静電容量の増加量を表わす。第３図よ
り明らかなように、光の波長が２５０ｎｍから７００ｎ
ｍにわたる可視域全体で光照射により静電容量が変化す
ることがわかる。したがって、この波長領域の光を含む
ほとんどの光源（例えば、キセノンランプ、ヘリウムネ
オンレーザ、発光ダイオード等）で書き込みができる。Here, Co represents the capacitance when no light is irradiated, and ΔC represents the amount of increase in the capacitance when the light is irradiated. As is clear from Figure 3, the wavelength of light is from 250nm to 700nm.
It can be seen that the capacitance changes due to light irradiation over the entire visible range over m. Therefore, writing can be performed using almost any light source that includes light in this wavelength range (for example, a xenon lamp, helium neon laser, light emitting diode, etc.).
なお、Ｍｎを添加した硫化亜鉛薄膜を発光層とする黄橙
色発光の薄膜ＥＬ素子については、すでに光による情報
書込み方法が考案されている（例えば、特願昭５０−４
３９９６号）。Note that a method for writing information by light has already been devised for a thin film EL element that emits yellow-orange light using a thin film of zinc sulfide doped with Mn as a light emitting layer (for example,
No. 3996).
しかしＺｎＳ ： Ｍｎ系の素子は３５Ｏｒ＋ｍの紫外
域にピークを持つ光感度特性を示すため、紫外光成分が
強い発光スペクトルを持った光源が必要とされ、光書き
込みに用いる光源がキセノンランプ等のごく限られたも
のに限定されたのに対し、本発明のＣａＳ：Ｅｕ薄膜Ｅ
Ｌ素子では、光源の選択範囲が広まり汎用性が高くなっ
ている。However, since ZnS:Mn-based elements exhibit photosensitivity characteristics with a peak in the ultraviolet region of 35 Or+m, a light source with an emission spectrum with a strong ultraviolet light component is required, and the light source used for optical writing is very small, such as a xenon lamp. In contrast, the present invention's CaS:Eu thin film E
The L element has a wider selection range of light sources and is more versatile.
（実施例） 以下に本発明の具体的な実施例を述べる。(Example) Specific examples of the present invention will be described below.
本発明で用いた薄膜ＥＬ素子は、以下の方法で作製した
。第１図において、まずガラス基板６上にスパンタリン
グ法でＩＴＯ透明電極４を２００ｎｍ形成し、ＥＣＲプ
ラズマｃｖＤ法により、酸化シリコンと窒化シリコンを
順次積層した絶縁膜３を１１００ｎ形成し、ユーロピウ
ムを０．１ ｍｏ１％添加した硫化カルシウムを蒸発源
とし加熱蒸発させると同時に、硫化水素プラズマを照射
し硫黄欠損を低減させながら薄膜形成を行い、膜Ｊｙ１
μｍの発光Ｊｉｌを形成する。その後、再びＥＣＲプラ
ズマＣＶＤ法により、窒化シリコン絶縁膜２を１１００
ｎ形成した後、電子ビーム蒸着法等によりアルミ電極５
を形成して素子とした。The thin film EL device used in the present invention was manufactured by the following method. In FIG. 1, first, an ITO transparent electrode 4 with a thickness of 200 nm is formed on a glass substrate 6 by a sputtering method, an insulating film 3 of 1100 nm is formed by successively laminating silicon oxide and silicon nitride by an ECR plasma CVD method, and 0 nm of europium is formed. .1 Mo1% calcium sulfide was used as an evaporation source to heat and evaporate it, and at the same time, hydrogen sulfide plasma was irradiated to form a thin film while reducing sulfur vacancies.
A luminescent Jil of μm is formed. Thereafter, the silicon nitride insulating film 2 was formed to a thickness of 1100 nm again by the ECR plasma CVD method.
After forming the aluminum electrode 5, an aluminum electrode 5 is formed using an electron beam evaporation method or the like.
was formed to form an element.
第２図は、この薄膜ＥＬ素子に交流電源７から電圧を印
加した時の、印加電圧に対する発光輝度特性の一例を示
す図であって、電圧昇圧時の発光輝度特性を実線Ｉで、
降圧時の発光輝度特性を破線ｎで示した。FIG. 2 is a diagram showing an example of the emission brightness characteristics with respect to the applied voltage when voltage is applied to this thin film EL element from the AC power source 7. The solid line I indicates the emission brightness characteristics when the voltage is increased.
The luminance characteristics during voltage reduction are indicated by a broken line n.
第４図はこの薄膜Ｌ−，Ｌ素子にＶｏの電圧を印加した
状態で、波長５６０ｎｍに最大発光強度を持つ緑色ダイ
オード（ＬＥＤ）の光を薄膜ＥＬ素子に照射した時の入
射光強度と薄膜ＥＬ素子の発光輝度を示す図である。こ
のうよな特性を持つ薄膜ＥＬ素子に波長５６０ｎｍに最
大発光強度を持つ緑色ダイオード（ＬＥＤ）を光源とし
たライトペンで光を照射すると、光が照射された画素の
み点灯して、光書き込みが確認された。また、書き込み
にょにる画素の絶縁破壊は全く見られなかった。Figure 4 shows the incident light intensity and the thin film when the thin film EL element is irradiated with light from a green diode (LED) that has a maximum emission intensity at a wavelength of 560 nm with a voltage of Vo applied to the thin film L- and L elements. FIG. 3 is a diagram showing the luminance of light emitted from an EL element. When a thin-film EL element with these characteristics is irradiated with light using a light pen whose light source is a green diode (LED) with a maximum emission intensity at a wavelength of 560 nm, only the pixels irradiated with the light will light up, resulting in optical writing. confirmed. Further, no dielectric breakdown of the pixels during writing was observed.
また、書き込んだ情報の消去方法は、消去したい画素の
維持電圧を第２図に示す■、まで下げることによって行
うことができる。Further, the written information can be erased by lowering the sustaining voltage of the pixel to be erased to the value ◯ shown in FIG. 2.
（発明の効果）
本発明の薄膜ＥＬ素子の情報書込み装置は、ＥＬ表示パ
ネルへの情報書き込みが光により行われるので、書き込
みによる画素破壊等を生じない。(Effects of the Invention) Since the information writing device for a thin film EL element of the present invention writes information to the EL display panel using light, no pixel destruction or the like occurs due to writing.
このため表示パネルの信頼性を向上させることができる
。また、表示パネルの駆動回路構成が簡単になるので、
装置のコストを大幅に低減できる。Therefore, the reliability of the display panel can be improved. In addition, since the display panel drive circuit configuration becomes simpler,
The cost of equipment can be significantly reduced.
さらにデイスプレー画面の任意の場所に座標検出装置を
併用することなく、確実に画像情報を入力することが可
能である。これらの特性があることから、本発明の装置
を用いれば、高信頼性の平面表示パネルや光入力形の画
像入力表示装置を、ＥＬパネルで実現することができる
。Furthermore, it is possible to reliably input image information to any location on the display screen without using a coordinate detection device. Because of these characteristics, if the device of the present invention is used, a highly reliable flat display panel or optical input type image input display device can be realized using an EL panel.
第１図は本発明で用いた薄膜Ｅ、Ｌ素子の構造を示す図
、
第２図は本発明で用いた薄膜ＥＬ素子の印加電圧に対す
る発光輝度のヒステリシス特性を示す図、第３図は本発
明で用いた薄膜ＥＬ素子の光照射時の容量変化の波長依
存性を示す図、
第４図は本発明で用いた薄膜ＥＬ素子に維持電圧Ｖｓを
印加し、波長５６０ｎｍに最大発光強度を持つ緑色ダイ
オード（ＬＥＤ）で光を照射した時の照射光強度と発光
輝度との関係を示す図、
第５図は従来の薄膜ＥＬ素子の構造を示す図、第６図は
従来の薄膜ＥＬ素子の印加電圧に対する発光輝度のヒス
テリシス特性と電気的駆動方式のタイムチャートを示す
図である。
１・・・ユーロピウム（Ｅｕ）を添加した硫化カルシウ
ム（ＣａＳ）発光層薄膜
２．３・・・絶縁層薄膜 ４・・・透明電極５・・・
背面電極 ６・・・ガラス基板７・・・交流電
源
９・・・ユーロピウム（Ｅｕ）を添加した硫化カルシウ
ム（ＣａＳ）発光層薄膜
ｔｏ、 １１・・・絶縁層薄膜
１３・・・背面電極
１２・・・透明電極
１４・・・ガラス基板
日本電信電話株式会社
第１
図
５−一−−貨１乞極
６−−−づ′ラス是才叉
７−−−−史九電源
第５図
７２−−−一透哨電紬
７３−−−一質面電劾
７４−−−一万うス是オ反
第４図
入力た強７堰、
第６図Fig. 1 is a diagram showing the structure of the thin film E and L elements used in the present invention, Fig. 2 is a diagram showing the hysteresis characteristics of the luminance luminance with respect to applied voltage of the thin film EL element used in the present invention, and Fig. 3 is a diagram showing the structure of the thin film EL element used in the present invention. A diagram showing the wavelength dependence of the capacitance change during light irradiation of the thin film EL element used in the invention. Figure 4 shows the peak emission intensity at a wavelength of 560 nm when a sustaining voltage Vs is applied to the thin film EL element used in the invention. A diagram showing the relationship between irradiated light intensity and luminance when light is irradiated by a green diode (LED). Figure 5 is a diagram showing the structure of a conventional thin film EL element. Figure 6 is a diagram showing the structure of a conventional thin film EL element. FIG. 3 is a diagram showing a time chart of hysteresis characteristics of light emission brightness with respect to applied voltage and an electrical drive method. 1... Calcium sulfide (CaS) light emitting layer thin film added with europium (Eu) 2.3... Insulating layer thin film 4... Transparent electrode 5...
Back electrode 6... Glass substrate 7... AC power source 9... Calcium sulfide (CaS) light emitting layer thin film to which europium (Eu) is added, 11... Insulating layer thin film 13... Back electrode 12. ...Transparent electrode 14...Glass substrate Nippon Telegraph and Telephone Corporation No. 1 Fig. 5-1--Cunnium 1 Beggar 6--Du'Las is useful 7-----History 9 Power source Fig. 5 72- ---Ichito Senden Tsumugi 73----Ichimmen Dengai 74---10,000 Usu is Obi Figure 4 Entered strong 7 weir, Figure 6
Claims (1)
ＣａＳ）薄膜を発光層とし、かつ印加電圧と発光輝度と
の関係にヒステリシス特性を示す薄膜ＥＬ素子の情報書
込み装置において、電圧上昇時の最小発光輝度と電圧降
下時の最大発光輝度との差が十分に大きい電圧値を振幅
とする交流電圧を印加する手段と、光を照射する手段と
を有することを特徴とする薄膜ＥＬ素子の情報書込み装
置。1. Calcium sulfide with added europium (Eu)
In an information writing device for a thin film EL element that uses a thin film (CaS) as a light-emitting layer and exhibits hysteresis characteristics in the relationship between applied voltage and luminance, the difference between the minimum luminance when the voltage increases and the maximum luminance when the voltage drops is 1. An information writing device for a thin film EL element, comprising means for applying an alternating current voltage having an amplitude of a sufficiently large voltage value, and means for irradiating light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63197834A JPH0249395A (en) | 1988-08-10 | 1988-08-10 | Data writing device of membranous el element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63197834A JPH0249395A (en) | 1988-08-10 | 1988-08-10 | Data writing device of membranous el element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0249395A true JPH0249395A (en) | 1990-02-19 |
Family
ID=16381120
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63197834A Pending JPH0249395A (en) | 1988-08-10 | 1988-08-10 | Data writing device of membranous el element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0249395A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005026224A (en) * | 2003-06-13 | 2005-01-27 | Matsushita Electric Ind Co Ltd | Light emitting element, display device and control method for display device |
-
1988
- 1988-08-10 JP JP63197834A patent/JPH0249395A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005026224A (en) * | 2003-06-13 | 2005-01-27 | Matsushita Electric Ind Co Ltd | Light emitting element, display device and control method for display device |
| JP4500594B2 (en) * | 2003-06-13 | 2010-07-14 | パナソニック株式会社 | LIGHT EMITTING ELEMENT, DISPLAY DEVICE AND DISPLAY DEVICE CONTROL METHOD |
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