LED LIGHTING DEVICE

摘要

An LED lighting device of embodiment comprising an LED light source which generates an ultraviolet light or a visible light, an axisymmetric transparent member which is provided over the light source and which is transparent to visible light, and an axisymmetric light scattering member disposed in the transparent member apart from the light source. A distance of closest approach L2 between the light source and the light scattering member, and an area C of a light emitting surface of the light source satisfy the settled relation. A length L1 of the light scattering member, and an absorption coefficient μ (1/mm) of the light scattering member satisfy the settled relation. A diameter d1 of the bottom surface of the light scattering member, the distance of closest approach L2, and a refractive index n of the transparent member satisfy the settled relation.

主权项

1. An LED lighting device comprising:
an LED light source which generates light in an ultraviolet light region or a visible light region; an axisymmetric transparent member which is provided over the LED light source and which is transparent to visible light; and an axisymmetric light scattering member disposed in the axisymmetric transparent member apart from the LED light source, wherein the LED light source has a light emitting surface with an area C, and has a substantially symmetrical light distribution around a light distribution symmetrical axis which substantially intersects at right angles with the light emitting surface, the axisymmetric transparent member has a first symmetrical axis which substantially corresponds to the light distribution symmetrical axis of the LED light source, and the axisymmetric transparent member is symmetrical to the first symmetrical axis, the axisymmetric light scattering member has a second symmetrical axis which substantially corresponds to the light distribution symmetrical axis of the LED light source, the axisymmetric light scattering member having a diameter d1 of a bottom surface and a length L1 along the second symmetrical axis is symmetrical to the second symmetrical axis, and a distance of closest approach L2 between the LED light source and the axisymmetric light scattering member, and the area C of the light emitting surface of the LED light source satisfy the relation represented by Expression (1),L2>C4πExpression(1) the length L1 of the axisymmetric light scattering member along the second symmetrical axis, and an absorption coefficient μ (1/mm) of the axisymmetric light scattering member satisfy the relation of Expression (2),L1≥log2μExpression(2) the diameter d1 of the bottom surface of the axisymmetric light scattering member, the distance of closest approach L2, and a refractive index n of the axisymmetric transparent member satisfy the relation of Expression (3),
d1≦2L2√{square root over (n2−1)}  Expression (3) a section of the axisymmetric light scattering member which intersects at right angles with the second symmetrical axis is included in a section of the axisymmetric transparent member in the former section, and a surface in which the axisymmetric transparent member is projected on a plane including the light emitting surface of the LED light source along the second symmetrical axis includes the light emitting surface of the LED light source.