Multifocal ophthalmic lens having chromatic aberration correction

1. An ophthalmic lens, comprising

an optic comprising an anterior surface, a posterior surface, and an optical axis, at least one of the anterior surface and the posterior surface having a surface profile including:

a base curvature;

a refractive region having the base curvature;

a diffractive region comprising a diffractive profile comprising plurality of diffractive steps, at least a portion of the diffractive profile being a combination of:

a base diffractive profile defining multiple foci for the ophthalmic lens;

an achromatizing structure that reduces longitudinal chromatic aberrations; and

the surface profile is defined as follows:

Sag achromatized_multifocal =Sag ( r )+ g ( r );

Sag ( r )= Z base ( r ) 0≤ r≤r 1 ;

Sag ( r )= Z base ( r )+ F diffractive ( r,T )+Δ′ 1 r 1 <r≤r 1 ′;

Sag ( r )= Z′ base ( r )+ F diffractive ( r,T )+Δ 1 ″ r 1 ′<r≤r 2 ′;

Sag ( r )= Z base ( r )+ F diffractive ( r,T )+Δ 1 ′″ r 2 ′<r≤r 2 ;

Sag ( r )= Z base ( r )+Δ 2 ′ r 2 <r≤r 3 ;

g

⁡

(

r

)

=

0

0

≤

r

≤

r

1

′

;

g

⁡

(

r

)

=

h

×

(

r

2

T

g

-

⌊

r

2

T

g

⌋

)

r

1

′

<

r

≤

r

2

′

;

g

⁡

(

r

)

=

0

r

2

′

<

r

≤

r

3

;

wherein:

Sag(r) defines the surface profile of the ophthalmic lens excluding the achromatizing structure;

g(r) defines the achromatizing structure;

r denotes a radial distance from the optical axis;

Z base (r) denotes the base curvature;

Z′ base (r) denotes a modified base curvature that takes into account a focus shift caused by the achromatizing structure;

F diffractive defines the base diffractive structure;

T denotes the period in r 2 space for the base diffractive structure;

r 1 , r 2 , r 3 , r 1 ′ and r 2 ′ denote junction points on the surface profile; and

Δ 1 ′, Δ 1 ″, Δ 1 ′″, and Δ 2 ′ are constants;

T g denotes a period in r 2 space of the achromatizing structure;

└ ┘ denotes a floor function, wherein └x┘=max{m∈z|m≤x} is a set of integers; and

h denotes a step height.

2. The ophthalmic lens of claim 1 , wherein the base curvature corresponds to a base optical power of the ophthalmic lens.

3. The ophthalmic lens of claim 1 , wherein:

the diffractive region extends from the optical axis to a first radial boundary; and

the refractive region extends from the first radial boundary to an edge of the optic.

4. The ophthalmic lens of claim 1 , wherein the base diffractive profile comprises an apodized diffractive profile.

5. The ophthalmic lens of claim 1 , wherein r 1 is equal to zero and r 3 defines an outer edge of the optic.

6. The ophthalmic lens of claim 1 , wherein:

Z

base

⁡

(

r

)

=

cr

2

1

+

1

-

(

1

+

k

)

⁢

c

2

⁢

r

2

+

a

2

⁢

r

2

+

a

4

⁢

r

4

+

a

6

⁢

r

6

+

…

+

a

n

⁢

r

n

;

r is a radial distance from the optical axis;

c is a base curvature of the surface;

k is a conic constant; and

a 2 , a 4 , a 6 , and a n are, respectively, second, fourth, sixth, and n th order coefficients.

7. The ophthalmic lens of claim 6 , wherein n=20.

8. The ophthalmic lens of claim 6 , wherein:

Z

base

′

⁡

(

r

)

=

c

′

⁢

r

2

1

+

1

-

(

1

+

k

′

)

⁢

c

′

2

⁢

r

2

+

a

2

′

⁢

r

2

+

a

4

′

⁢

r

4

+

a

6

′

⁢

r

6

+

…

+

a

n

′

⁢

r

n

;

r denotes a radial distance from the optical axis;

c′ denotes a base curvature of the surface;

k′ denotes a conic constant; and

a′ 2 , a′ 4 , a′ 6 , and a′ n are, respectively, second, fourth, sixth, and n th order coefficients; and at least one of c≠c′, k≠k′, a 2 ≠a′ 2 , a 4 ≠a′ 4 , a 6 ≠a′ 6 , a n ≠a′ n .

9. The ophthalmic lens of claim 8 , wherein n=20.

10. The ophthalmic lens of claim 1 , wherein:

T g =T.

11. The ophthalmic lens of claim 1 , wherein:

T g =NT ; or

T=NT g ;

wherein N is an integral.

12. The ophthalmic lens of claim 1 , wherein:

h=N h λ/( n IOL −n ocularmedia );

N h is an integral;

λ denotes a design wavelength;

n IOL denotes a refractive index of ophthalmic lens; and

n ocularmedia denotes a refractive index of an ocular media of a patient.