Light emitting device
AssigneeNichia Corporation
InventorMasatsugu Ichikawa
Life of this patent
Estimating the term…
Abstract
A light emitting device capable of improving both color unevenness and emission output power is provided. The light emitting device includes a semiconductor light emitting element including a semiconductor layer that emits primary light; and a fluorescent material layer disposed on the light emitting side of the semiconductor light emitting element, that absorbs a part of the primary light and emits secondary light having a wavelength longer than that of the primary light; and emits light of blended color of the primary light and the secondary light of the light emitting element, and further includes a scattering layer in which particles having a mean particle size D that satisfies the inequality: 20 nm<D≦0.4×λ/π are dispersed in a transparent medium.
Claims22
A light emitting device comprising:
- a semiconductor light emitting element including a semiconductor layer that emits primary light;
- and
- a fluorescent material layer disposed on the light emitting side of the semiconductor light emitting element, that absorbs a part of the primary light and emits secondary light having a wavelength longer than that of the primary light, the light emitting device emitting light of blended color of the primary light and the secondary light, wherein
- the light emitting device further comprises a scattering layer, in which particles are dispersed in a transparent medium, on the light emitting side of the fluorescent material layer, said particles having a mean particle size D that satisfies Inequality equation 1:
- 20 nm<D≦0.4×λ/π
- wherein λ is the wavelength of the primary light propagating in the transparent medium, and
- the scattering layer scatters the primary light and causes the primary light to emit from the light emitting device.
A light emitting device comprising:
- a semiconductor light emitting element including a semiconductor layer that emits primary light;
- and
- a fluorescent material layer disposed on the light emitting side of the semiconductor light emitting element, that absorbs a part of the primary light and emits secondary light having a wavelength longer than that of the primary light, the light emitting device emitting light of blended color of the primary light and the secondary light, wherein
- the light emitting device further comprises a scattering layer, in which particles are dispersed in a transparent medium, on the light emitting side of the fluorescent material layer, said particles having a mean particle size D that satisfies Inequality equation 1:
- 20 nm<D≦0.4×λ/π
- wherein λ is the wavelength of the primary light propagating in the transparent medium,
- the scattering layer scatters the primary light and causes the primary light to emit from the light emitting device,
- the particles are formed from an inorganic material having a higher refractive index than that of the transparent medium, and
- a peak wavelength of the primary light emitted by the semiconductor light emitting element is from 420 to 500 nm.
Dependencies are inferred from the claim text.