Abstract: According to one embodiment, a light-emitting unit includes a light-emitting section, a diffusion cover, and a reflector. The light-emitting section includes an LED element. The diffusion cover diffuses light emitted from the light-emitting section. The reflector controls the light diffused by the diffusion cover.

Abstract: According to one embodiment, a light-emitting unit includes a light-emitting section, a diffusion cover, and a reflector. The light-emitting section includes an LED element. The diffusion cover diffuses light emitted from the light-emitting section. The reflector controls the light diffused by the diffusion cover.

Abstract: A light-emitting diode lighting apparatus includes a light source including plural grouped light-emitting diodes, plural lighting circuit parts to perform lighting control of the respective grouped light-emitting diodes of the light source individually, and a dimming control part that inputs a dimming signal from a dimming part and controls an output of each of the lighting circuit parts according to the dimming signal, and sequentially changes, when a dimming gradation is changed, outputs of the plural lighting circuit parts to new gradations in one period of the dimming signal.

Abstract: In a Fresnel lens which is made of a lens material whose refraction index is n, and focuses light beam from a light source at a specified radiation view angle ?, and has plural N pieces of circular lens surfaces arranged concentrically around a common optical axis, and plural circular rise surfaces arranged adjacent alternately between these lens surfaces, and two lens surfaces adjacent via at least one of the rise surfaces are concave surfaces, and tangent lines and at the intersecting point with the rise surfaces of the shape of a cross section passing through the optical axis of those lens surfaces intersect at the outside with respect to the optical axis, and when the angle formed between these tangent lines is defined as ?, a relational equation ???/(2 n N) stands.

Abstract: In a Fresnel lens which is made of a lens material whose refraction index is n, and focuses light beam from a light source at a specified radiation view angle ?, and has plural N pieces of circular lens surfaces arranged concentrically around a common optical axis, and plural circular rise surfaces arranged adjacent alternately between these lens surfaces, and two lens surfaces adjacent via at least one of the rise surfaces are concave surfaces, and tangent lines and at the intersecting point with the rise surfaces of the shape of a cross section passing through the optical axis of those lens surfaces intersect at the outside with respect to the optical axis, and when the angle formed between these tangent lines is defined as ?, a relational equation ???/(2 n N) stands.