Limited echelette lens, systems and methods
An ophthalmic lens with a circular surface structure and limited adjacent echelettes that provides enhanced image quality across an extended range of foci.
1. An ophthalmic lens, comprising:
an anterior face and a posterior face, the faces disposed about an optical axis;
at least one diffractive profile imposed on the anterior face or the posterior face, the at least one diffractive profile consisting of an inner echelette and from 1 to 4 peripheral echelettes, wherein the inner echelette and the 1 to 4 peripheral echelettes each comprises a parabolic optical zone; and
a refractive region between an innermost one of the peripheral echelettes and the inner echelette, wherein the peripheral echelettes are not separated by a refractive region.
2. The ophthalmic lens of claim 1 , wherein the echelettes are characterized by a surface area between 1 and 7 square millimeters.
3. The ophthalmic lens of claim 1 , wherein the echelettes have the same surface area.
4. The ophthalmic lens of claim 1 , wherein the inner echelette has a diameter within a range from about 1 mm to about 5 mm.
5. The ophthalmic lens of claim 1 , wherein the lens further comprises a peripheral portion characterized by a spherical curve or an aspherical curve.
6. The ophthalmic lens of claim 1 , wherein the echelettes further comprise transitions characterized by a step height having a value within a range from about 0.5 μm and about 4 μm.
7. The ophthalmic lens of claim 5 , wherein the step heights provide a phase shift between about 0.25 and about 3 times the design wavelength.
8. The ophthalmic lens of claim 6 , wherein the step height for at least 2 echelettes differ.
9. The ophthalmic lens of claim 6 , wherein the surface area for at least 2 echelettes differ.