Lens, corresponding lighting device, lighting installation and method

A lighting device, comprising:

• at least one lens, the lens comprising:
• a lenticular body having a planar light input surface and a curved light output surface,
• the lenticular body providing a light propagation path from the input surface to the output surface along a lens axis, wherein the lenticular body includes first and second mutually orthogonal sectional planes intersecting at the lens axis, wherein the curvature values of the output surface in the second sectional plane have an average value higher than the average value of the curvature values of the output surface in the first sectional plane;
• wherein the lenticular body is longer along the first sectional plane than along the second sectional plane;
• wherein the points of the output surface of the lens have curvature values, with positive curvature values indicative of convexity of the output surface directed outwardly of the lens,
• wherein lens comprises a central region around the lens axis and a peripheral region surrounding the central region,
• wherein the curvature values of the output surface of the lens comprise peak values at the peripheral region and a pair of valley values at the central region between the peak values at the peripheral region, wherein a further peak value at the lens axis is arranged between the pair of valley values;
• and wherein the further peak value is equal to or greater than the peak values at the peripheral region;
• and
• a light radiation source coupled with the lens to emit along the lens axis light radiation to propagate through the lens from the light input surface to the light output surface.

A lighting installation comprising:

• at least one light radiation source to generate light radiation propagating along an axis,
• a plurality of lenses, each lens comprising:
• a lenticular body having a planar light input surface and a curved light output surface,
• the lenticular body providing a light propagation path from the input surface to the output surface along a lens axis, wherein the lenticular body includes first and second mutually orthogonal sectional planes intersecting at the lens axis, wherein the curvature values of the output surface in the second sectional plane have an average value higher than the average value of the curvature values of the output surface in the first sectional plane;
• wherein the lenticular body is longer along the first sectional plane than along the second sectional plane;
• wherein points of the output surface of the lens have curvature values, with positive curvature values indicative of convexity of the output surface directed outwardly of the lens,
• wherein the lens comprises a central region around the lens axis and a peripheral region surrounding the central region,
• wherein the curvature values of the output surface of the lens comprise peak values at the peripheral region and a pair of valley values at the central region between the peak values at the peripheral region, wherein a further peak value at the lens axis is arranged between the pair of valley values;
• and wherein the further peak value is equal to or greater than the peak values at the peripheral region;
• wherein the plurality of lenses are coupleable to the at least one light radiation source wherein radiation therefrom propagates along said axis from the light input surface to the light output surface of the lens,
• wherein the plurality of lenses includes different lenses which differ from one another for the curvature values of the light output surface.