Radiation sources

• US 3,995,299 A
• Filed: 10/07/1975
• Issued: 11/30/1976
• Est. Priority Date: 10/15/1974
• Status: Expired due to Term

• Current Assignee: The secretary of state for defence in her Britannic Majesty's Government of the United Kingdom of Great Britain And Northern Ireland
• Original Assignee: Secretary of State For Industry In Her Britannic Majesty's Government of The United Kingdon of Great Britain and Northern Ireland
• Inventors: Partridge, Roger Hugh
• Primary Examiner(s): Edlow, Martin H.
• Application Number:
  US05/620,450
• Time in Patent Office: 420 Days
• Field of Search: 357/8, 357/61, 357/2, 313/498, 313/504, 313/503, 526/4, 428/515, 252/511, 252/518
• US Class Current: 257/40
• CPC Class Codes: F21K 2/08 activated by an electric field, i.e. electrochemiluminescence
• CPC Class Codes: H05B 33/00 Electroluminescent light sources
• CPC Class Codes: Y10T 428/31909 Next to second addition polymer from unsaturated monomers

Abstract

A radiation source comprising a lamina of amorphous or predominantly amorus polymer material having appreciable electrical charge mobility and a low ionization potential; a strong electron donor; a strong electron acceptor; and preferably at least one fluorescent additive; electrical connections being provided by which an electric current may be passed through the thickness of said lamina to excite radiation therefrom.

Claims

1. A radiation source comprising a lamina of amorphous, or predominantly amorphous, polymer material having appreciable electrical charge mobility, and a low ionization potential;

a strong electron donor;

a strong electron acceptor, and electrical connections by which an electric current may be passed through the thickness of said lamina to excite radiation from said radiation source.

2. A radiation source according to claim 1 having in the said polymer material at least one luminescent additive.

3. A radiation source according to claim 2 in which the lamina is a thin translucent film of at least predominantly amorphous polymer material, which has sufficiently high electron affinity to allow anion formation;

the strong electron donor is in contact with one side of said polymer film and at least in part is in a first electrically conducting layer which is an anion layer formed by reacting the electron donor with the said polymer, the electron donor being strong enough to allow at least virtually complete transfer of an electron to at least one of said polymer and additive;

the strong electron acceptor is in contact with the other side of said polymer film and is in a second electrically conducting layer which is a cation layer formed by reacting the electron acceptor with the said polymer, the electron acceptor being strong enough to allow at least virtually complete extraction of an electron from at least one of the polymer and additive;

at least one of said electrically conducting layers being translucent and at least one of said anion layer and cation layer being a charge injector layer relative to the polymer material;

whereby when in use an electric current is passed in an approrpiate sense through the electrically conducting layers and polymer film in series, light is emitted from the said radiation source.

4. A radiation source according to claim 2 in which there is high efficiency of transfer of excitation energy from the polymer to a luminescent additive.

5. A radiation source according to claim 2 in which excitation energy is transferred from one luminescent additive to another luminescent additive.

6. A radiation source according to claim 2 in which any luminescent additive is selected from the group consisting of perylene, tetraphenylbutadiene, acridine orange.

7. A radiation source according to claim 2 in which the electron donor is an alkali metal.

8. A radiation source according to claim 7 in which the alkali metal is one of the group consisting of potassium, rubidium, cesium.

9. A radiation source according to claim 2 in which the electron acceptor is a metal salt.

10. A radiation source according to claim 9 in which the metal salt is antimony pentachloride.

11. A radiation source according to claim 2 in which the polymer material is polyvinylcarbazole.

12. A radiation source according to claim 3 in which the polymer film is polyvinylcarbazole and has a thickness in the range from about 1/2 to about 11/2 micrometer.

13. A radiation source according to claim 1 provided with chemically inert surroundings.