| 摘要 |
Diffusing reflector elements 14s are assigned respectively to a plurality of sector segments S centering on the optical axis Ax of reflector 14; the surface geometry of each diffusing reflector element 14s is set as a convex curved surface referenced to a paraboloid of revolution P which, among a plurality of paraboloids of revolution P having different focal lengths that center on the optical axis Ax with a common focus F lying at a single point on the optical axis, passes the edge of a side a closer to the optical axis of the sector segment S to which said diffusing reflector element 14s is to be assigned on a free curved surface Cf. As a result, the diffusing reflected light from each diffusing reflector element 14s can be controlled in diffusion with reference to the direction of the optical axis Ax and, in addition, when the lighting device is lit up and viewed right from the front, the entire part of the reflective surface 14a is visible and can be seen bright although in a discrete manner. Further, no shade is formed between circumferentially adjacent diffusing reflector elements 14s, thus assuring the lighting device to look sufficiently attractive. element.
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