Double progressive spectacle lens
View Patent ↗A double-progressive spectacle lens in which the progressive action is distributed over the front and rear surfaces of the double-progressive spectacle lenses and described by the quotient Q Q =Add vfl /Add Gesamt where Add vfl represents the increase in the surface dioptric power along the principal line on the front surface between the distance area and the near area, and ADD Gesamt represents the increase in the total dioptric power along the principal line between the distance area and the near area, and the fraction Q increases with growing distance area effect F: ⅆ Q ( F ) ⅆ F ⩾ 0.
1. A set of double-progressive spectacle lenses in which the progressive action is distributed over the front and rear surfaces of the double-progressive spectacle lenses and described by
Q =Add vfl /Add Gesamt
wherein
Add vfl represents the increase in the surface dioptric power along the principal line on the front surface between the distance-vision area and the near-vision area,
Add Gesamt represents an increase in total dioptric power along the principal line between the distance-vision area and the near-vision area among lenses within the set, and
Q increases with an increasing power F in the distance-vision area such that:
ⅆ
Q
(
F
)
ⅆ
F
⩾
0.
2. A set of double-progressive spectacle lenses according to claim 1 , wherein Q increases in accordance with a linear function of spherical distance-vision area power F:
Q ( F )= Q 0 +Q 1 ·F
where Q 0 =0.5 and Q 1 =0.04/dpt.
3. A set of double-progressive spectacle lenses according to claim 1 , wherein Q increases in accordance with an approximately linear function of spherical distance-vision area power F:
Q ( F )= Q 0 ±dQ 0 +( Q 1 ±dQ 1 )· F,
where Q 0 =0.5 and Q 1 =0.04/dpt,
and where dQ 0 =0.2 and Q 1 =0.02/dpt.
4. A set of double-progressive spectacle lenses according to claim 1 , wherein Q increases in accordance with an approximately linear function of spherical distance-vision area power F:
Q ( F )= Q 0 ±dQ 0 ±( Q 1 ±dQ 1 )· F,
where Q 0 =0.5 and Q 1 =0.04/dpt,
and where dQ 0 =0.1 and Q 1 =0.01/dpt.
5. A set of double-progressive spectacle lenses according to claim 1 , wherein Q lies within the following values:
Spherical Effect
Nominal value Q
Minimum Q
Maximum Q
≦−10
dpt
0.2
0
0.4
−5
dpt
0.3
0.1
0.5
0
dpt
0.5
0.3
0.7
+ 5
dpt
0.7
0.5
0.9
≧+10
dpt
0.8
0.6
1
as a function of the distance-vision area power.
6. A set of double-progressive spectacle lenses according to claim 1 , wherein the change in Q with the distance-vision area power is greater than 0.01/dpt for powers less than 5 dpt in absolute value.
7. A set of double-progressive spectacle lenses according to claim 1 , wherein the change in Q with the distance-vision area power is greater than 0.01/dpt for powers greater than 5 dpt in absolute value.
8. A set of double-progressive spectacle lenses according to claim 1 , wherein Q<0 or >1.
9. Method for fabricating a set of double-progressive spectacle lenses, the method comprising a step of distributing the progressive power of the spectacle lenses over the front and rear surface of the spectacle lenses such that among lenses within the set the quotient Q:
Q =Add vfl /Add Gesamt
increases with increasing power F in the distance-vision area:
ⅆ
Q
(
F
)
ⅆ
F
>
0
wherein
Add vfl represents the increase in the surface dioptric power along the principal line on the front surface between the distance-vision area and the near-vision area, and
Add Gesamt represents the increase in the total dioptric power along the principal line between the distance-vision area and the near-vision area.