An optical device for modifying light distribution

A set of molds comprising:

• a first mold having a form suitable for manufacturing, by mold casting, a first piece of transparent material constituting a first optical element of an optical device,
• a second mold having a form suitable for manufacturing, by mold casting, a second piece of transparent material constituting a second optical element of the optical device, and
• a third mold having a form suitable for manufacturing, by mold casting, a third piece of transparent material constituting a third optical element of the optical device, wherein:
• the first optical element comprises a first surface for modifying a distribution of light exiting the first optical element through the first surface, and
• the second optical element comprises a second surface facing towards the first surface and for further modifying the distribution of the light entering the second optical element through the second surface and a third surface for further modifying the distribution of the light exiting the second optical element through the third surface,
• wherein the first optical element is rotatable with respect to the second optical element around a geometric optical axis of the optical device, and one of the first and second surfaces comprises convex areas and another one of the first and second surfaces comprises concave areas for at least partly compensating for an optical effect of the convex areas when the second optical element is in a first rotational position with respect to the first optical element so that the convex areas and the concave areas are aligned with respect to each other, wherein a combined optical effect of the first and second surfaces is changeable by rotating the first optical element from the first rotational position towards a second rotational position in which the concave areas and the convex areas are non-aligned with respect to each other, and wherein the third optical element comprises a fourth surface facing towards the third surface of the second optical element, wherein the third and the fourth surfaces have grooves so that the grooves of the third surface are parallel with the grooves of the fourth surface, and the third optical element is linearly moveable with respect to the second optical element along a direction of the geometric optical axis of the optical device.

An illumination device comprising:

• a light source, and
• an optical device for modifying a distribution of light emitted by the light source,
• wherein the optical device comprises:
• a first optical element comprising a first surface for modifying a distribution of light exiting the first optical element through the first surface, and
• a second optical element comprising a second surface facing towards the first surface and for further modifying the distribution of the light entering the second optical element through the second surface and a third surface for further modifying the distribution of the light exiting the second optical element through the third surface,
• wherein the first optical element is rotatable with respect to the second optical element around a geometric optical axis of the optical device, and one of the first and second surfaces comprises convex areas and another one of the first and second surfaces comprises concave areas for at least partly compensating for an optical effect of the convex areas when the second optical element is in a first rotational position with respect to the first optical element so that the convex areas and the concave areas are aligned with respect to each other, wherein a combined optical effect of the first and second surfaces is changeable by rotating the first optical element from the first rotational position towards a second rotational position in which the concave areas and the convex areas are non-aligned with respect to each other, and wherein the optical device comprises a third optical element comprising a fourth surface facing towards the third surface of the second optical element, wherein the third and the fourth surfaces have grooves so that the grooves of the third surface are parallel with the grooves of the fourth surface, and the third optical element is linearly moveable with respect to the second optical element along a direction of the geometric optical axis of the optical device.