US 5,422,489 A · Light emitting device

Abstract

A glowing device comprises a substrate which is substantially transparent to radiation in a first spectral region and supports a nanoparticle or nanocrystal active layer, which is a thin layer constituted of separated tiny particles with nanometer dimensions, typically 100 .ANG. or less in size. When the nanocrystal layer comprises one of certain luminescent materials activated with certain activators, the layer when excited will efficiently emit radiation characteristic of the activator. Since the particles making up the active layer are very small, the layer can be made very thin, of the order of 1000 .ANG. or less. With this small thickness, the layer will be substantially transparent to radiation except for a narrow range of radiation capable of being absorbed by the active layer and thus capable of exciting the nanocrystal layer. When thus excited, the active layer will emit radiation in a narrow wavelength range. When the incident radiation extends over a broad spectral region, then part of the spectral energy will be absorbed and converted to the radiation characteristic of the nanocrystal layer, and the rest will pass through the nanocrystal layer and substantially transparent substrate, which to an observer will appear to glow with light in the narrow wavelength range. By providing multiple layers of nanocrystals, each responsive to a different part of the spectrum, a larger part of the incident radiation energy will be converted to glowing light.

Claims24

Dependent claims

A glowing device comprising:

(a) a substrate substantially transparent in a first spectral region and substantially absorbent in a second spectral region,
(b) a thin active layer on said substrate, said active layer comprising separate nanoparticles capable of emitting radiation in said first spectral region in response to incident radiation in a third spectral region, said active layer having a thickness less than about 1000 Angstroms,
(c) said device being positioned such that the active layer faces in the direction of and can receive incident radiation in said third spectral region.

Dependencies are inferred from the claim text.

Light emitting device

Life of this patent

Light emitting device

Life of this patent

Abstract

Claims24