Thin film EL element

• US 4,590,128 A
• Filed: 02/22/1985
• Issued: 05/20/1986
• Est. Priority Date: 02/24/1984
• Status: Expired due to Fees

• Current Assignee: Hoya Corporation
• Original Assignee: Hoya Corporation
• Inventors: Kawai, Hisao
• Primary Examiner(s): HERBERT JR, THOMAS
• Application Number:
  US06/704,380
• Time in Patent Office: 452 Days
• Field of Search: 428/913, 428/411.1, 428/917, 428/426, 428/457, 428/432, 427/165, 427/164, 313/509, 313/512
• US Class Current: 428/411.1
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: H05B 33/24 of metallic reflective layers H05B33/26 takes precedence
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

An electroluminescence element has a luminescence layer sandwiched between a transparent electrode and a back electrode so as to generate luminescence upon an application of an electric field between the transparent and back electrodes, wherein a light reflector is arranged behind the back electrode, and a light absorber is arranged at a side of a light extraction side of the electroluminescence element.

Claims

1. An electroluminescense element having a luminescence layer sandwiched between tranparent electrodes and back electrodes formed on a transparent substrate respectively in the form of a matrix, so as to generate luminescence upon the application of an electric field between said transparent electrodes and back electrodes, wherein a light reflector for reflecting light passing between adjacent back electrodes is arranged behind said back electrodes, and a light absorber for absorbing visible, reflected light of said electroluminiescence element is arranged on the light extracting side of said transparent electrodes.

2. An element according to claim 1 wherein a visible light reflectance of said light reflector is substantially the same as that of a region with said back electrodes when viewed from the side of said transparent electrodes, a transmittance of said light absorber falls within a range between 10% and 70%, and a wavelength dispersion of transmittance of the visible light falls within a range of ±

10%.

3. An element according to claim 2, wherein said light reflector comprises a metal plate.

4. An element according to claim 2, wherein said light absorber comprises a plastic material.

5. An element according to claim 2, wherein said light absorber comprises a glass substrate and at least one dielectric layer formed on at least one major surface of said glass substrate.

6. An element according to claim 5, wherein said glass substrate comprises an alkali metal oxide with iron and cobalt, and said at least one dielectric layer is constituted by either a single layer consisting of one of magnesium fluoride and silicon dioxide or at least two layers consisting of at least two materials selected from the group consisting of magnesium fluoride, silicon dioxide, titanium dioxide and hafnium oxide.

7. An element according to claim 2, wherein said light absorber comprises a glass substrate and a thin light-absorbing film formed on at least one of two major surfaces of said glass substrate.

8. An element according to claim 7, wherein said glass substrate comprises an alkali metal oxide with iron and cobalt, and said thin light-absorbing film comprises at least one material selected from the group consisting of lead-tellurium, cadmium-tellurium and carbon.

9. An element according to claim 2, wherein said light reflector comprises a sealing plate disposed above said transparent substrate with an intervening adhesive means for a sealing purpose, and a metal film for reflection formed on at least one major surface of said sealing plate.

10. An element according to claim 9, wherein said reflecting metal film comprises a metal selected from the group consisting of chrome, tantalum, nickel, nickel-chrome, molybdenum and aluminum.

11. An element according to claim 1, wherein said sealing plate comprises a member selected from the group consisting of a multicomponent glass and a quartz glass.