Patent ID: 7697219

Claim:
An optical device, defined in a polar coordinate system, having its optical axis coincident with said polar coordinate system's z-axis axis, whereby said optical device transforms a first distribution of light, propagating along said optical axis, into a second distribution of light, propagating towards a focal region, comprising: a. a first optically active surface that is radially symmetric about the optical axis and providing continuous first and second partial derivatives of its surface function at all surface points and in all directions that are tangent to said first optically active surface at each said surface point, except at the location of said optical axis. b. a second optically active surface, displaced along said optical axis apart from said first optically active surface, and providing a plurality of radially directed facets each having two active and symmetric local surfaces arranged at an inclined Geometric Facet Angle to each other and extending radially away from the vicinity of the optical axis and having continuous first and second partial derivatives of its surface function in the polar angle direction, except for discrete polar angles of said polar coordinate system where said first partial derivative in the polar angle direction is discontinuous, c. said second optically active surface providing continuous first and second partial derivatives of its surface function in the radial direction of said polar coordinate system of said optical device, d. each of said facets having said Geometric Facet Angle that continuously varies as a function of the radial coordinate of said optical device, f. a focal region which is symmetrically located about said optical axis, and g. a transparent dielectric medium having its boundaries defined predominately by said first optically active surface and said second optically active surface and having a refractive index that is higher than the refractive index of a surrounding medium, whereby said first distribution of light is transformed jointly by said first optically active surface and said second optically active surface to said focal region by a series of light redirections comprising at least: a refraction through said first surface, two total internal reflections on said two active and symmetric local surfaces of said radially directed facets, thereby allowing said first distribution of light to be transformed into said second distribution of light at said focal region.