Patent ID: 9581860
Date: 2017-02-28
CPC Classifications: G02B,G02F,H01L,H05B

Claim:
1. An illumination device for emitting light including secondary light obtained through wavelength conversion of primary light, comprising: a light source that emits primary light; and a wavelength conversion element that performs wavelength conversion on at least a portion of the primary light emitted from the light source, said wavelength conversion element including an incident surface where the primary light is incident, an emission surface that is opposite to the incident surface and that emits light including secondary light, and a phosphor layer including phosphors and polymers, said phosphors absorbing at least a portion of the primary light emitted from the light source to emit the secondary light, which is polarized, and said polymers having a birefringence, wherein said phosphors have an anisotropic structure and are aligned generally along a first direction, wherein said polymers have polymer molecules that are aligned generally along said first direction, wherein an angle formed by a direction of a transition dipole moment of each of the phosphors to a delayed phase axis of each of the polymer molecules with respect to the secondary light emitted from the phosphors towards the polymer molecules is 0° to 45°, and wherein said wavelength conversion element includes said phosphor layer in a plurality such that the plurality of phosphor layers is arranged from a side of the incident surface to a side of the emission surface, and peak wavelengths of the phosphors included in the respective plurality of phosphor layers differ from one another such that the peak wavelengths of the phosphors become progressively lower from the side of the incident surface to the side of the emission surface.