Controlled-luminance lighting device

DETAILED DESCRIPTION The purpose of the present invention is to provide a lighting device of the type defined above, which is designed to enable a low luminance, at the same time ensuring a high efficiency.
According to the invention, the above purpose is achieved thanks to the fact that, in a lighting device of the type defined at the beginning of this description: the primary reflector is formed by a plurality of cup-like elements set alongside one another, having a generally parabolic shape, through which there extends said light source; and the secondary reflector is constituted by a tray-like element with a curved surface, the bottom wall of which has a cusp in a position longitudinally corresponding to said light source.
The cup-like elements set alongside one another, in practice, envelop the light source completely for some stretches and perform the function of angular control of the light beam emitted by the light source.
This enables an effective angular control of the light beam with a structure of small dimensions.
The portions of the light source that extend between each pair of contiguous cup-like elements would be directly exposed outwards, in the sense that the relative luminous flux would not be gathered by the cup-like elements.
In order to recover also this luminous flux, the primary reflector further conveniently includes a tile, which extends between each pair of contiguous cup-like elements and is formed by a pair of opposed curved flanges.
In a variant of the device according to the invention, the tray-like element constituting the secondary reflector is, in turn, formed by a plurality of tray-like elements set alongside one another.