Electroluminescent element

• US 5,126,214 A
• Filed: 03/05/1990
• Issued: 06/30/1992
• Est. Priority Date: 03/15/1989
• Status: Expired due to Term

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Kusomoto, Tadashi, Hosokawa, Chishio, Tokailin, Hiroshi
• Primary Examiner(s): Robinson, Ellis P.
• Assistant Examiner(s): Nold, Charles R.
• Application Number:
  US07/488,702
• Time in Patent Office: 848 Days
• Field of Search: 428/690, 428/917, 428/691, 428/212, 428/216, 313/503, 313/504, 313/502, 313/505, 313/506-509
• US Class Current: 428/690
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: G09F 9/33 being semiconductor devices, e.g. diodes
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 85/111 comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
• CPC Class Codes: H10K 85/113 Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
• CPC Class Codes: H10K 85/60 Organic compounds having low molecular weight H10K85/10 - H10K85/50 take precedence
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/621 Aromatic anhydride or imide compounds, e.g. perylene tetra-carboxylic dianhydride or perylene tetracarboxylic di-imide
• CPC Class Codes: H10K 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
• CPC Class Codes: H10K 85/654 comprising only nitrogen as heteroatom H10K85/652 takes precedence
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole
• CPC Class Codes: H10K 85/6574 comprising only oxygen in the heteroaromatic polycondensed ring system, e.g. cumarine dyes
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick

Abstract

An electroluminescent element comprising an electroluminescent (EL) material part which emits a near ultraviolet ray of light and a fluorescent material part which absorbs the ultraviolet light emitted from the electroluminescent material and emits a fluorescence in a visible light range from blue to red. The electroluminescent element provides for emission of lights with a wide range of wavelength and three elementary colors of blue, green and red can be expressed by appropriate combinations of the organic EL material and the fluorescent material. Consequently, the electroluminescent element provides for a full color display.

Claims

1. An electroluminescent element comprising an organic electroluminescent material part which emits a blue light and at least one fluorescent material part which absorbs said blue light and emits a fluorescence in a visible light range from bluish green to red light said fluorescent material part exists outside of the electroluminescent material part.

2. The electroluminescent element as claimed in claim 1, wherein the fluorescent material part comprises a plurality of fluorescent materials.

3. The electroluminescent element as claimed in claim 1 which is formed by laminating the organic electroluminescent material part and the fluorescent material part.

4. The electroluminescent element as claimed in claim 1 wherein the organic electroluminescent material part is placed horizontally in line with the fluorescent material part.

5. The electroluminescent element as claimed in claim 1, wherein the organic electroluminescent material part comprises a compound which emits a blue light, sandwiched between two electrodes, at least one of which electrodes is transparent or semitransparent.

6. The electroluminescent element as claimed in claim 5, wherein the organic electroluminescent material part comprises a laminate of a layer of the compound which emits a blue light and a hole injection layer, said laminate being sandwiched between two electrodes, at least one of which electrodes is transparent or semitransparent.

7. The electroluminescent element as claimed in claim 1, wherein the fluorescent material part comprises a fluorescent material comprising a stilbene-based dye, a coumarin-based dye, a cyanine-based dye, a pyridine-based dye, a xanthene-based dye or an oxadine-based dye.

8. The electroluminescent element as claimed in claim 1, wherein the organic electroluminescent material is selected from the group consisting of ##STR17##

9. The electroluminescent element as claimed in claim 1, wherein the fluorescent material part comprises at least one dye selected from the group consisting of 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyrylene)-4-H-pyran, 1-ethyl-2-(4-(p -dimethylaminophenyl)-1,3-butadienyl)-pyridium-perchorat, rhodamine B, rhodamine G and 2,3,5,6-H,4H-tetrahydro-8-trichloromethylquinolizino-(9,9a,1-gh)-coumarin.

10. The electroluminescent element as claimed in claim 3, wherein the organic electroluminescent material comprises a film with a thickness of 5nm to 5-82 m;

the fluorescent material part comprises a film with a thickness of 100 nm to 5 nm; and

the fluorescent material comprises a dye dispersed in a resin, said dye having a concentration of 10^-2 to 10^-4 moles/liter based on the resin.

11. The electroluminescent element as claimed in claim 1, wherein the organic electroluminescent material part comprises a compound which emits a blue light, sandwiched between two electrodes, at least one of which is transparent or semitransparent and said element is formed by laminating the organic electroluminescent material part and the fluorescent material part.

12. The electroluminescent element as claimed in claim 1, wherein the organic electroluminescent material part comprises a compound which emits a blue light, sandwiched between two electrodes, at least one of which is transparent or semitransparent and said electroluminescent material part is placed horizontally in line with the fluorescent material.

13. The electroluminescent element as claimed in claim 5, wherein the organic electroluminescent material part comprises a laminate of a layer of the compound which emits a blue light and a hole injection layer, said laminate being sandwiched between two electrodes, at least one of which electrodes is transparent or semitransparent and said element is formed by laminating the organic electroluminescent material part and the fluorescent material part.

14. The electroluminescent element as claimed in claim 5, wherein the organic electroluminescent material part comprises a laminate of a layer of the compound which emits a blue light and a hole injection layer, said laminate being sandwiched between two electrodes, at least one of which electrodes is transparent or semitransparent and the organic electroluminescent material part is placed horizontally in line with the fluorescent material part.

15. The electroluminescent element as claimed in claim 1, wherein the organic electroluminescent material is selected from the group consisting of ##STR18## said electroluminescent element is formed by laminating the organic electroluminescent material part and the fluorescent material part.

16. The electroluminescent element as claimed in claim 1, wherein the organic electroluminescent material is selected from the group consisting of ##STR19## wherein the organic and electroluminescent material is placed horizontally in line with the fluorescent material part.