EP0500382B1 - Moisture proof thin film electroluminescent panel - Google Patents

Moisture proof thin film electroluminescent panel Download PDF

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Publication number
EP0500382B1
EP0500382B1 EP92301434A EP92301434A EP0500382B1 EP 0500382 B1 EP0500382 B1 EP 0500382B1 EP 92301434 A EP92301434 A EP 92301434A EP 92301434 A EP92301434 A EP 92301434A EP 0500382 B1 EP0500382 B1 EP 0500382B1
Authority
EP
European Patent Office
Prior art keywords
thin film
panel
film electroluminescent
sheet
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.)
Expired - Lifetime
Application number
EP92301434A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0500382A2 (en
EP0500382A3 (en
Inventor
Takuo Yamashita
Takashi Ogura
Masaru Yoshida
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Publication of EP0500382A2 publication Critical patent/EP0500382A2/en
Publication of EP0500382A3 publication Critical patent/EP0500382A3/en
Application granted granted Critical
Publication of EP0500382B1 publication Critical patent/EP0500382B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/02—Details
    • H05B33/04—Sealing arrangements, e.g. against humidity
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces

Definitions

  • the present invention relates to a moistureproof thin film electroluminescent panel used for a display device of a personal computer, a wordprocessor or the like.
  • a conventional manufacturing method of thin film electroluminescent panels as shown in Fig. 9, lower transparent electrodes 3, a lower insulating layer 4, an electroluminescent layer 5, an upper insulating layer 6 and upper electrodes 7 are deposited on a glass substrate 2 in a stacked manner to form an electroluminescent (hereinafter referred to as EL for brevity) device 1 and, thereafter, a lining backup glass plate 8 is put on said EL device 1 by adhering the periphery thereof to that of the glass substrate 2 with an adhesive agent 9 of epoxy resin in order to prevent moisture from penetrating into the EL device.
  • EL electroluminescent
  • silicone oil in which silica gel powder and black powder are dispersed to give a moisture absorbing property is filled into a space 11 between the EL device 1 and the backup glass plate 8 through a hole 10 of the same and, thereafter, the hole 10 is sealed tightly by plugging a "TORR SEAL ®" 12 thereinto.
  • a thin film electroluminescent panel similar to the above-described one is known from JP-A-2-75193, in which a black gelatinous or solid insulating material is filled and sealed in a void between a panel substrate and a back substrate. This material is stated to improve the contrast of the display.
  • JP-A-61-290693 there is disclosed a moistureproof structure of the EL device wherein a laminated film is used for preventing moisture from penetrating. In this manufacturing method, no structure for absorbing penetrated moisture is provided and nothing is considered to enhance the contrast of the EL device.
  • EP-A-0 350 907 discloses a thin film electroluminescent panel according to the preamble of claim 1, and further comprising a moisture-absorbing sheet disposed between the moistureproof sheet and the EL device.
  • the moisture-absorbing sheet is coloured black in order to enhance the display contrast.
  • An object of the present invention is to provide a thin film EL panel having a highly moistureproofed structure and offering a high contrast.
  • the present invention provides a thin film electroluminescent panel comprising a transparent substrate, a thin film electroluminescent device formed on said substrate, and a flexible moistureproof sheet which covers said device and is sealed to said substrate around the periphery of said device, characterised in that a coating of black silicone resin of addition reaction type envelops the outer surface of said device covered by said sheet.
  • the back side of the thin film EL device is double-sealed with the coating of black silicone resin of addition reaction type and the moistureproof sheet.
  • powder-like or pellet-like moisture absorbing material is arranged for absorbing moisture penetrating through the moistureproof sheet.
  • this powder-like or pellet-like material is arranged by dispersing it in the black silicone resin coating.
  • it is arranged between the black silicone resin coating and the moistureproof sheet, either on the surface of the coating or in a gas-permeable sack.
  • a sheet-like moisture-absorbing body is arranged between the black silicone resin coating and the moistureproof sheet.
  • the moisture absorbers mentioned above can enhance the moisture resistance of the thin film EL panel.
  • the thin film EL panel In order to enhance the moistureproof property of the thin film EL panel, it is desirable to pierce at least one hole of a small diameter in the moistureproof sheet through which moisture existing inside of the EL panel can be dehydrated. After dehydration, the hole is sealed by a suitable sealing means. In this case, the moisture introduced into the EL panel during the fabrication process thereof can be dehydrated and, accordingly, the reliability of moisture-proof is enhanced much more.
  • the contrast thereof is highly enhanced since the EL device is lined with the black coating and, thereby, the quality of display is much improved.
  • the manufacturing process is simplified and the EL panel can be made thinner and lighter.
  • Figs. 1 to 5 and 7 show partial sectional views of thin film EL panels according to the present invention. Through all these Figs., the same reference numerals denote the same elements as those used in Fig. 9.
  • the thin film EL panels shown in Figs. 1 to 3 have a substantially same fundamental structure except for the manner of arrangement of moisture absorbing means.
  • the reference numeral 1 denotes a thin film EL device.
  • Thin film EL device 1 comprises lower transparent stripe electrodes 3 formed on a transparent substrate 2 such as a glass substrate in parallel to each other at an equal pitch, a lower insulating layer 4, an EL layer 5, an upper insulating layer 6 and upper stripe electrodes 7 arranged in parallel to each other at an equal pitch and in direction orthogonal to that of the lower transparent electrodes3. These elements 3 to 7 are formed stacked one on the other.
  • the reference numeral 13 denotes a layer of a black silicone resin. This black silicone resin layer 13 is formed by painting the black silicone resin so as to cover the EL device 1.
  • the reference numeral 14 denotes powder like or pellet-like moisture absorber composed of powder or pellets of silica (SiO 2 ), molecular sieve or the like. In the structure shown in Fig. 1, the moisture absorber 14 is dispersed in the black silicone resin 13. In the structure shown in Fig. 2, it is arranged on the black silicone layer 13. Further, in Fig. 3, it is contained in a gas-permeable sack 20 and the sack 20 is arranged on the black silicone layer 13.
  • the reference numeral 18 denotes a moistureproof sheet which is composed of a laminated sheet having such a structure that a metal foil 16 of 5 to 50 ⁇ m thickness is sandwiched by organic resin films 15 and 17 of 5 to 50 ⁇ m thickness such as polyester films. These organic resin films 15 and 17 may be made of different materials.
  • the moistureproof effect of said sheet 18 is mainly obtained by the metal foil 16 since it is impermeable against moisture.
  • the organic resin films 15 and 17 are mainly for protection of the surface of the metal foil 16 and for insulation from the EL device 1, but are desirably made of a resin material having a low moisture-permeability.
  • the moistureproof sheet 18 covers the EL device 1 so as to define a space 19 therebetween and is bonded to the transparent substrate 2 along the periphery thereof with an epoxy resin adhesive agent 9 to seal the inside of the EL panel completely.
  • the moisture absorber 14 absorbs moisture existing inside of the moistureproof sheet 18, the credibility of the EL panel against moisture is highly enhanced.
  • gas discharge from the EL device 1 is done by raising the temperature up to 200°C or more in a vacuum to remove residual moisture as much as possible.
  • the black silicone resin 13 in which powder-like or pellet-like moisture absorber 14 is dispersed is painted or printed on the thin film EL device 1 in dry N 2 gas or dry air at room temperature.
  • the liquid of black silicone resin is prepared by mixing, at room temperature, powder-like or pellet-like moisture absorber 14 having been vacuum-dehydrated at a temperature of 100°C or more into the liquid of black silicone resin having been dehydrated and deformed in a vacuum.
  • the black silicone resin 13 is hardened by maintaining the same at a constant temperature for a predetermined time according to the property thereof (for instance at 150°C for one hour). After hardening of the black silicone resin 13, the moistureproof sheet 18 is adhered with an epoxy adhesive agent 9 in dry N 2 gas or dry air. Accordingly, dry N 2 gas or dry air is filled in the space 19.
  • the predetermined amount of the moisture absorber 14 having been vacuum-dehydrated by heating the same at 100°C or more is arranged on the hardened black silicone resin 13.
  • the gas-permeable sack 20 containing a predetermined amount of the moisture absorber 14 is vacuum-dehydrated by heating the same up to 100°C or more beforehand, and it is put on the hardened black silicone resin 13.
  • the use of the sack makes treatment of the moisture absorber easier.
  • the moistureproof sheet 18 is adhered to the periphery of the substrate 2 with the epoxy resin adhesive agent 9 in dry N 2 gas or dry air.
  • the moisture absorber 14 is a sheet made from non-woven fabric or the like which contains silica micro powder, molecular sieve powder or the like therein.
  • the EL panel uses the latter type of black silicone resin.
  • This black silicone resin 13 enhances the contrast of the EL panel by forming the black background and contributes to relax stresses generated in the EL panel.
  • Fig. 6 shows the number of broken pixels of the EL panel in relation with the hardness of the hardened black silicone resin.
  • the EL panel vibrates with a small amplitude during action thereof and, accordingly, the breaking property of the pixel is affected by stresses exerted thereto from the black silicone resin 13 coated thereon. In other words, it is strongly related to the hardness of the hardened black silicone resin.
  • the hardness of the black silicone resin 13 should be smaller or equal to 20 when it is measured according to JIS C 2123.
  • the black silicone resin prefferably has a dielectric strength equal to or larger than 1 x 10 5 V/cm in order to avoid damage to electrodes and pixels due to discharges among electrodes during action of the EL panel.
  • a thin film EL panel having no moisture absorber therein. If it is used in a well-conditioned atmosphere, a reasonably long life will be guaranteed even in this case.
  • Fig. 7 shows a sixth preferred embodiment of the present invention.
  • the thin film EL panel shown in Fig. 7 has a substantially same structure as that shown in Fig. 4 except for a hole 21 of a small diameter, for example of about 6mm, pierced in the moistureproof sheet 18. This small hole 21 is provided for dehydrating the inner space 19 of the EL panel to remove the moisture introduced thereinto during the fabrication process of the EL panel.
  • the EL panel Upon dehydrating the inner space 19, the EL panel is charged into a vacuum chamber (not shown) and is vacuum-dehydrated therein by raising the inner temperature up to 100°C or more. Then, dry N 2 gas or air is filled into the vacuum chamber and the hole 21 is sealed quickly by adhering a small strip 22 having the same layered structure as that of the moistureproof sheet 18 from the outside thereof. By heating and hardening epoxy resin 9' applied to the under side of the small strip 22, the hole 21 is sealed surely and, thus, the fabrication process of the EL panel is completed.
  • the number of small holes to be pierced may be two or more. Further, it is desirable to pierce the small hole in the moistureproof sheet 18 beforehand for smooth and quick dehydrating operation. However, it is also possible to pierce the small hole upon dehydrating the EL panel.
  • the moisture having penetrated into the inner space of the EL panel during the fabrication process thereof is surely dehydrated resulting in a much higher reliability against degradation due to moisture.
  • Fig. 8 shows experimental data related to the life-time of sealing obtained under three sealing conditions.
  • the life-time of sealing at room temperature and humidity was estimated from an acceleration life-time test wherein thin film EL panels were operated to repeat light emission in an atmosphere at a temperature of 85°C and a relative humidity of 85%.
  • the life-time of sealing is greatly affected by an ambient humidity upon sealing the EL panel but the dehydration operation can remove undesirable effects based on a high ambient humidity perfectly.
  • the life-time of sealing demanded for actual use is about 5 x 10 4 hours and this criterion can be easily satisfied by the present preferred embodiment of the present invention, as indicated by the case C in Fig. 8.
  • the background of the display is black. This enhances the contrast of display, the quality of display and the appearance of the panel.
  • the sealing process of the EL panel is simplified since the moistureproof sheet is adhered to the substrate in a dry atmosphere in the present invention. Further, the EL panel according to the present invention can be made thinner and lighter when compared with the conventional one wherein the backup glass plate is used.
  • the present invention can be applied to both dot matrix type and segment type EL devices.

Landscapes

  • Electroluminescent Light Sources (AREA)
EP92301434A 1991-02-21 1992-02-21 Moisture proof thin film electroluminescent panel Expired - Lifetime EP0500382B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP27186/91 1991-02-21
JP3027186A JPH04267096A (ja) 1991-02-21 1991-02-21 薄膜ｅｌパネル

Publications (3)

Publication Number Publication Date
EP0500382A2 EP0500382A2 (en) 1992-08-26
EP0500382A3 EP0500382A3 (en) 1993-09-22
EP0500382B1 true EP0500382B1 (en) 1996-12-27

Family

ID=12214049

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92301434A Expired - Lifetime EP0500382B1 (en) 1991-02-21 1992-02-21 Moisture proof thin film electroluminescent panel

Country Status (4)

Country Link
EP (1) EP0500382B1 (fi)
JP (1) JPH04267096A (fi)
DE (1) DE69216123T2 (fi)
FI (1) FI105882B (fi)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106132868A (zh) * 2013-12-12 2016-11-16 追踪有限公司 通过多层膜层压进行的微机电系统囊封

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09148066A (ja) * 1995-11-24 1997-06-06 Pioneer Electron Corp 有機ｅｌ素子
JP2001057474A (ja) * 1999-08-19 2001-02-27 Auto Network Gijutsu Kenkyusho:Kk 有機ｅｌ表示装置
EP1208726A1 (en) * 1999-09-03 2002-05-29 Uniax Corporation Encapsulation of organic electronic devices
IT1313899B1 (it) * 1999-10-25 2002-09-26 Getters Spa Sistema assorbitore di umidita' per schermi comprendenti diodiorganici emettitori di luce e processo per la sua produzione
US20030015687A1 (en) 2001-01-08 2003-01-23 Sud-Chemie Ag Plate-shaped pressed bodies
JP3409764B2 (ja) 1999-12-28 2003-05-26 日本電気株式会社 有機ｅｌ表示パネルの製造方法
JP3447653B2 (ja) * 2000-03-16 2003-09-16 日東電工株式会社 エレクトロルミネッセンス素子用部材およびそれを内蔵したエレクトロルミネッセンス素子
JP3558578B2 (ja) 2000-03-23 2004-08-25 日東電工株式会社 固定部材およびそれを用いたエレクトロルミネッセンス素子ならびにその背面基板
KR20030030380A (ko) * 2001-10-10 2003-04-18 엘지.필립스 엘시디 주식회사 유기전계 발광소자
JP2004311246A (ja) * 2003-04-08 2004-11-04 Tohoku Pioneer Corp 有機ｅｌパネル及びその製造方法
KR20060007161A (ko) 2004-07-19 2006-01-24 엘지전자 주식회사 액정표시장치
US7687119B2 (en) 2005-04-04 2010-03-30 Henkel Ag & Co. Kgaa Radiation-curable desiccant-filled adhesive/sealant
US8159128B2 (en) * 2006-07-05 2012-04-17 Ifire Ip Corporation Sealed thick film dielectric electroluminescent display
KR102179329B1 (ko) * 2013-11-28 2020-11-18 삼성디스플레이 주식회사 표시 장치
US20160299332A1 (en) * 2015-04-09 2016-10-13 Qualcomm Mems Technologies, Inc. Pre-release encapsulation of electromechanical system devices

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0350907A2 (en) * 1988-07-14 1990-01-17 Sharp Kabushiki Kaisha Thin film electroluminescent panel

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5669795A (en) * 1979-11-09 1981-06-11 Nippon Telegraph & Telephone Thin film electroluminescent element sealing method
JPS62295090A (ja) * 1986-06-14 1987-12-22 双葉電子工業株式会社 電界発光表示パネルとその製造方法
JPS63105494A (ja) * 1986-10-22 1988-05-10 アルプス電気株式会社 薄膜ｅｌパネル
JPH01149397A (ja) * 1987-12-07 1989-06-12 Ricoh Co Ltd エレクトロルミネッセンス素子
US4963788A (en) * 1988-07-14 1990-10-16 Planar Systems, Inc. Thin film electroluminescent display with improved contrast
JPH02197071A (ja) * 1989-01-26 1990-08-03 Sharp Corp 薄膜ｅｌパネル

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0350907A2 (en) * 1988-07-14 1990-01-17 Sharp Kabushiki Kaisha Thin film electroluminescent panel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106132868A (zh) * 2013-12-12 2016-11-16 追踪有限公司 通过多层膜层压进行的微机电系统囊封

Also Published As

Publication number Publication date
DE69216123D1 (de) 1997-02-06
FI920728A0 (fi) 1992-02-20
JPH04267096A (ja) 1992-09-22
DE69216123T2 (de) 1997-05-15
EP0500382A2 (en) 1992-08-26
EP0500382A3 (en) 1993-09-22
FI105882B (fi) 2000-10-13
FI920728A (fi) 1992-08-22

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