Flexible electroluminescent film laminate

• US 4,684,353 A
• Filed: 08/19/1985
• Issued: 08/04/1987
• Est. Priority Date: 08/19/1985
• Status: Expired due to Term

• Current Assignee: Electroluminscent Technologies Corporation
• Original Assignee: DUNMORE Corp. (Steel Partners Holdings LP)
• Inventors: deSouza, Antonio S.
• Primary Examiner(s): Ramsey, Kenneth J.
• Application Number:
  US06/766,443
• Time in Patent Office: 715 Days
• Field of Search: 445/49, 445/51-52, 445/24, 156/289, 156/344, 156/285, 427/64, 427/71, 427/66
• US Class Current: 445/51
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

Electroluminescent elements of high light intensity and long useful life, operating at comparatively low energy input, are obtained by directly bonding to a supported web of thin plastic film without intermediate adhesive a layer of resin containing EL phosphor thoroughly and uniformly dispersed therein, and depositing on the surface of said resin a fine layer of a transparent electrode consisting essentially of indium tin oxide. In alternative embodiments the said resin layer is sandwiched between thin deposited layers of alkaline earth metal titanate.

Claims

1. The method of producing a thin flexible electroluminescent element which comprises the steps of:

releaseably mounting on a carrier web comprised of a relatively thick flexible plastic film a preformed thin plastic base film,

thoroughly and uniformly dispersing in a thermoplastic resin matrix particles of an electroluminescent phosphor,

depositing the obtained dispersion as a coating layer on the exposed upper surface of the mounted base film,

bonding the phosphor-containing resin coating to the mounted base film by passing the thus coated film and carrier web through calendering rollers under pressure and at elevated temperature;

with or without first stripping the carrier web from the coated base film, directly sputtering on the exposed surface of the phosphor-containing resin matrix a thin transparent layer of electrical conducting material to serve as a front electrode;

applying to a selected portion of the transparent front electrode an electrical connection terminal formed of a metal having high electrical conductivity;

and, after stripping the carrier web from the base film, applying to one or more discrete areas of the exposed underside the base film, a metal facing of high electrical conductivity to serve as one or more back electrodes.

2. The method as defined in claim 1 wherein said base film is selected from the group consisting of polyester resins and polyvinyl fluoride resins.

3. The method as defined in claim 2 wherein said base film has a thickness of no more than about 10 microns.

4. The method as defined in claim 2 wherein said base film has a thickness in the range of about 5 to 8 microns.

5. The method as defined in claim 4 wherein said base film is polyethylene terephalate.

6. The method as defined in claim 5 wherein said transparent front electrode comprises indium tin oxide.

7. The method as defined in claim 5 wherein said resin matrix comprises a resin selected from the group consisting of saturated and unsaturated polyester resins, polyvinyl fluoride, acrylates, methacrylates, cyanoethyl starch, cyanoethyl cellulose and polyurethanes.

8. The method as defined in claim 5 wherein said resin matrix is a polyester resin.

9. The method as defined in claim 8 wherein said resin matrix has dispersed therein an alkaline earth metal titanate.

10. The method as defined in claim 8 wherein said resin matrix has dispersed therein indium oxide in an amount not exceeding 10% by total weight of said deposited resin coating layer.

11. The method as defined in claim 8 wherein said phosphor is activated zinc sulfide coated with polyvinylidene fluoride.

12. The method as defined in claim 8 wherein said phosphor is activated zinc sulfide coated with phsohporic acid.

13. The method as defined in claim 8 wherein said phosphor is activated zinc sulfide coated with a quatermary ammonium compound.

14. The method as defined in claim 8 wherein said phosphor is activated zinc sulfide coated with one or more organic silane compounds.

15. The method as defined in claim 8 wherein said phosphor is activated zinc sulfide coated with copper sulfate.

16. The method as defined in claim 5 wherein said phosphor-containing resin matrix is an unsaturated polyester resin.