Ophthalmic lens having an extended depth of focus
View Patent ↗In certain embodiments, an ophthalmic lens includes an optic having an anterior surface, a posterior surface, and an optical axis. At least one of the anterior surface and the posterior surface includes a first zone extending from the optical axis to a first radial boundary and a second zone extending from the first radial boundary to the edge of the optic. The first zone includes an inner region and an outer region separated by a phase shift feature, the phase shift comprising a ridge extending outwardly from the inner region and the outer region.
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 comprising:
a first zone extending from the optical axis to a first radial boundary; and
a second zone extending from the first radial boundary to the edge of the optic;
wherein:
the first zone comprises an inner region having a first curvature and an outer region having the first curvature;
a phase shift feature separating the inner region and the outer region, the phase shift feature comprising a ridge of increased thickness relative to adjacent portions of the inner region and the outer region, the ridge comprising a ridge surface having the first curvature, a first phase shift step extending outwardly from the inner region to the ridge surface, and a second phase shift step extending inwardly from the ridge surface to the outer region.
2. The ophthalmic lens of claim 1 , wherein the inner region and the outer region have the same optical power.
3. The ophthalmic lens of claim 1 , wherein:
the first curvature comprises a first aspheric profile;
the second zone has a second curvature comprising a second aspheric profile, the second aspheric profile being different than the first aspheric profile.
4. The ophthalmic lens of claim 1 , wherein a surface profile of the first zone is defined as follows:
Z first zone =Z base +Z 2ps
wherein:
Z
base
=
cr
2
1
+
1
-
(
1
+
k
)
c
2
r
2
+
a
2
r
2
+
a
4
r
4
+
a
6
r
6
r is a radial distance from the optical axis;
c is a base curvature of the first zone;
k is a conic constant; and
a 2 , a 4 , and a 6 are, respectively, second, fourth, and sixth order coefficients; and
wherein:
Z
2
ps
=
{
0
r
0
≤
r
<
r
1
(
r
-
r
1
)
/
(
r
2
-
r
1
)
*
Δ
1
r
1
≤
r
<
r
2
Δ
1
r
2
≤
r
<
r
3
Δ
1
+
(
r
-
r
3
)
/
(
r
4
-
r
3
)
*
Δ
2
r
3
≤
r
<
r
4
Δ
1
+
Δ
2
r
4
≤
r
<
r
5
;
r is a radial distance from the optical axis;
r 0 is the optical axis;
the inner region extends from the optical axis to r 1
the phase shift feature extends from r 1 to r 4 ;
the outer region extends from r 4 to r 5 ;
Δ 1 is a step height of the phase shift feature relative to the inner region; and
Δ 2 is a step height of the phase shift feature relative to the outer region.
5. The ophthalmic lens of claim 4 , wherein a surface profile of the second zone is defined as follows:
Z second zone =Z base +(Δ 1 +Δ 2 )
6. The ophthalmic lens of claim 1 , wherein a surface profile of the optic is defined as follows:
Z optic =Z base +Z 2ps
wherein:
Z
base
=
{
cr
2
1
+
1
-
(
1
+
k
)
c
2
r
2
+
a
2
r
2
+
a
4
r
4
+
a
6
r
6
r
0
≤
r
<
r
5
c
′
r
2
1
+
1
-
(
1
+
k
′
)
c
′
2
r
2
+
a
2
′
r
2
+
a
4
′
r
4
+
a
6
′
r
6
r
5
≤
r
<
r
6
;
Z
2
ps
=
{
0
0
≤
r
<
r
1
(
r
-
r
1
)
/
(
r
2
-
r
1
)
*
Δ
1
r
1
≤
r
<
r
2
Δ
1
r
2
≤
r
<
r
3
Δ
1
+
(
r
-
r
3
)
/
(
r
4
-
r
3
)
*
Δ
2
r
3
≤
r
<
r
4
Δ
1
+
Δ
2
Δ
3
r
4
≤
r
<
r
5
r
5
≤
r
<
r
6
;
r is a radial distance from the optical axis;
r 0 is the optical axis;
the first zone extends from optical axis to r 5 , with the inner region extending from the optical axis to r 1 , the phase shift feature extending from r 1 to r 4 , and the outer region extending from r 4 to r 5 ;
the second zone extends from r 5 to r 6 ;
c is a base curvature of the first zone;
k is a conic constant of the first zone; and
a 2 , a 4 , and a 6 are, respectively, second, fourth, and sixth order coefficients of the first zone;
c′ is a base curvature of the second zone;
k′ is a conic constant of the second zone; and
a 2 ′, a 4 ′, and a 6 ′ are, respectively, second, fourth, and sixth order coefficients of the second zone;
Δ 1 is a step height of the phase shift feature relative to the inner region; and
Δ 2 is a step height of the phase shift feature relative to the outer region; and
Δ
3
=
[
(
cr
5
2
)
(
1
+
(
1
-
(
1
+
k
)
c
2
r
5
2
)
)
+
a
4
r
5
4
+
a
6
r
5
6
+
Δ
1
+
Δ
2
]
-
[
(
c
′
r
5
2
)
(
1
+
(
1
-
(
1
+
k
′
)
c
′2
r
5
2
)
)
+
a
4
′
r
5
4
+
a
6
′
r
5
6
]
.
7. The ophthalmic lens of claim 6 , wherein:
at least one of the following c≠c′, k≠k′, a 2 ≠a 2 ′, a 4 ≠a 4 ′, and a 6 ≠a 6 ′ is true; and
Δ 3 is a constant added to the base curvature of the second zone to ensure continuity between the first zone and the second zone.
8. The ophthalmic lens of claim 1 , wherein a step height of the first phase shift step is greater than a step height of the second phase shift step.