Optical system for ophthalmic surgical laser

1. A laser system for ophthalmic surgery, comprising:

a laser source, to generate a pulsed laser beam;

an XY scanner,

to receive the pulsed laser beam, and

to output an XY-scanning beam, scanned in two directions transverse to a Z axis;

a Z scanner,

to receive the XY-scanning beam; and

to output an XYZ-scanning beam, scanned in addition along the Z axis;

the Z scanner comprising

a first lens group to output a beam having an intermediate focal plane; and

a movable lens group to receive the beam through the intermediate focal plane and to collimate the beam in a variable manner; and

an objective to receive the collimated beam from the Z scanner and to focus the beam into a focal spot in a target region.

2. The ophthalmic laser system of claim 1 , wherein:

the Z scanner is configured to scan a Z focal depth of the focal spot in the target region within a Z scanning range of 5 millimeter to 10 millimeter.

3. The ophthalmic laser system of claim 1 , wherein:

the Z scanner is configured to scan a Z focal depth of the focal spot in the target region within a Z scanning range of 0 millimeter to 15 millimeter.

4. The ophthalmic laser system of claim 1 , wherein

the movable lens group can be moved along the Z axis by a distance between 5 and 50 millimeters.

5. The ophthalmic laser system of claim 1 , wherein:

the first lens group comprises 2-10 lenses; and

the movable lens group comprises 2-10 lenses.

6. The ophthalmic laser system of claim 1 , wherein:

the first lens group comprises, sequentially from an input side

a first lens group with a positive refractive power;

a meniscus lens, having a convex surface facing the input side; and

a second lens, having a concave surface facing the input side.

7. The ophthalmic laser system of claim 1 , wherein:

the first lens group has five lenses, the lenses having indices of refraction and sequentially labeled surfaces with corresponding curvatures, all within ranges given in the following table:

Surface

Curvature [1/m]

Distance [mm]

Refractive Index n

1

  (0, 1.5)

(5, 25)

 (1.6, 1.93)

2

(22, 28)

(12, 22) 

(1.6, 1.7)

3

(−17, −14)

(0.5, 12)  

1

4

(7.0, 8.5)

(15, 29) 

(1.65, 1.8) 

5

(−19, −13)

(3, 14)

1

6

(14, 18)

(8, 12)

(1.6, 1.7)

7

  (0, 9.3)

(6, 12)

1

8

(−28, −21)

(1, 5) 

(1.65, 1.75)

9

(−15, −6)

8. The ophthalmic laser system of claim 7 , wherein:

the first lens group has five scaled lenses in place of the five lenses, having scaled curvatures corresponding to the curvatures of the five lenses multiplied by a scale factor α and scaled distances in place of the distances, scaled by a scale factor 1/α, wherein

the scale factor α has a value between 0.3 and 3.

9. The ophthalmic laser system of claim 1 , wherein:

the movable lens group comprises, sequentially from an input side

a meniscus lens, having a concave surface facing the input side;

a negative lens with a negative refractive power; and

a positive lens group with a positive refractive power.

10. The ophthalmic laser system of claim 1 , wherein:

the movable lens group has four lenses, the lenses having indices of refraction and sequentially labeled surfaces with corresponding curvatures, all within ranges given in the following table:

Surface

Curvature [1/m]

Distance [mm]

Refractive Index n

1

(−25, −10)

(3, 7)

(1.7, 1.8)

2

(−25, −28)

(0, 2)

1

3

(−43, −24)

(1.5, 5)  

 (1.5, 1.62)

4

 (8.5, 19.4)

(26, 31)

1

5

(−6.2, −4.6)

(10, 16)

(1.53, 1.6) 

6

(−18.4, −14.7)

(34, 49)

1

7

(1.9, 4.2)

 (8, 14)

(1.58, 1.61)

8

 (−11, −9.0)

11. The ophthalmic laser system of claim 10 , wherein:

the movable lens group has four scaled lenses in place of the four lenses, having scaled curvatures corresponding to the curvatures of the four lenses multiplied by a scale factor α and scaled distances in place of the distances, scaled by a scale factor 1/α, wherein

the scale factor α has a value between 0.3 and 3.

12. The ophthalmic laser system of claim 1 , wherein:

the movable lens group is adjustable to change at least one characteristic of the XYZ scanning beam exiting the Z scanner, the characteristics comprising:

a convergence, a beam diameter, a Z focal depth, and a numerical aperture NA.

13. The ophthalmic laser system of claim 1 , wherein:

the movable lens group is configured to adjust a numerical aperture NA and a Z focal depth of the XYZ scanning beam essentially independently from each other.

14. The ophthalmic laser system of claim 1 , wherein:

the Z scanner is configured to focus a beam, emanating from an exit pivot point of the XY scanner into an entrance pivot point of the objective.

15. The ophthalmic laser system of claim 14 , wherein:

the entrance pivot point of the objective is inside the objective.

16. The ophthalmic laser system of claim 14 , wherein:

a position of the entrance pivot point of the objective is adjustable by moving the movable lens group.

17. The ophthalmic laser system of claim 1 , wherein:

the Z scanner is configured to modify an exit pivot point of the XY scanner into an entrance pivot point of the objective.

18. The ophthalmic laser system of claim 17 , wherein:

the entrance pivot point of the objective is inside the objective.

19. The ophthalmic laser system of claim 1 , wherein:

the first lens group is one of a movable lens group and a fixed lens group.

20. A method of ophthalmic surgery, the method comprising the steps of:

generating a pulsed laser beam;

XY scanning the pulsed laser beam in two directions transverse to a Z direction with an XY scanner;

Z scanning the XY scanned beam along a Z direction with a Z scanner by

focusing the XY scanned beam onto an intermediate focal plane with a first lens group;

receiving the beam from the intermediate focal plane by a movable beam scanner;

collimating the beam into an adjustable entrance pivot point of an objective by the movable beam scanner; and

focusing the beam onto an XYZ scanned focal spot in a target region by the objective.

21. The method of claim 20 , wherein the Z scanning step comprises:

adjusting the movable beam scanner to change at least one characteristic of the XYZ scanning beam exiting the Z scanner, the characteristics comprising:

a convergence, a beam diameter, a Z focal depth, and a numerical aperture NA.

22. The method of claim 20 , wherein the Z scanning step comprises:

adjusting a numerical aperture NA and a Z focal depth of the XYZ scanning beam essentially independently from each other.