Bandpass filter for use in light emitting device and light emitting device using the same
US9518718B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 2013 |
| Grant date | Dec 13, 2016 |
| Priority date | — |
| Expiry date | Dec 29, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H20/851
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Provided is a bandpass filter for a light emitting device that can improve the light emission efficiency in use for a light emitting device, and a light emitting device that can obtain the high light emission efficiency by using the bandpass filter. The light emitting device includes a substrate; a light emitting element disposed over the substrate; a phosphor-containing layer containing at least one kind of phosphor; and a bandpass filter disposed over a surface of the phosphor-containing layer on the light emitting element side, the bandpass filter including a multilayer film having a plurality of first and second dielectric layers, the second dielectric layer being disposed over the first dielectric layer. The bandpass filter has a transmittance of 60% or more for light having a light emission peak wavelength of the light emitting element at an incident angle of 0 to 85°, and another transmittance of 40% or less for light having a light emission peak wavelength of at least one kind of phosphor at an incident angle of a Brewster's angle (θb)+5° (θb+5°) to 85° of the bandpass filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.