Contact element for laser machining

Patent metadata

Field	Value
Publication number	US-9265658-B2
Application number	US-59050205-A
Country	US
Kind code	B2
Filing date	Jan 25, 2005
Priority date	Feb 25, 2004
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

An optical contact element for coupling a laser processing device to an object to be processed is described, wherein the laser processing device focuses a scanned laser beam through a surface of the object into a certain region of the object and the contact element comprises an entrance side for receiving the scanned laser radiation and an exit side imparting a defined surface curvature to the surface of the object upon contact therewith, wherein a diffractive optical element is provided on the entrance side, which element reduces the angle of incidence of the laser radiation on the surface of the object.

First claim

The invention claimed is:

1. An optical contact element for coupling a laser processing device to an object to be processed, wherein
the laser processing device focuses a scanned laser beam through a surface of the object into a certain region of the object and
the contact element comprises a plano-concave base body a concave surface of which provides an exit side and a planar surface of which provides an entrance side, and a diffractive optical element being formed on or at a surface of the entrance side, the exit side imparting a defined surface curvature to the surface of the object upon contact therewith, wherein
the entrance side cross section is larger than a cross section of the scanned laser beam which is scanned over the entrance side, and
the diffractive optical element being configured to reduce the angle of incidence of the laser radiation on an interface between the surface of the object and the exit side of the contact element peripheral to an optical axis, the angle of incidence being measured from a normal to the defined surface curvature on the surface of the object across the exit side that imparts the defined surface curvature to the surface of the object.

2. The contact element as claimed in claim 1 , wherein the defined surface curvature is substantially rotation-symmetrical to an optical axis of the laser processing device.

3. The contact element as claimed in claim 2 , wherein the diffractive optical element diffracts laser radiation incident at a distance from the optical axis towards the optical axis, with the angle of diffraction increasing as a distance from the optical axis increases.

4. The contact element as claimed in claim 3 , wherein the diffractive optical element comprises a grating structure having a number of grating lines depending on the distance from the optical axis.

5. The contact element as claimed in claim 4 , wherein a line number of the grating is at least 220 lines per millimeter and not above 500 lines per millimeter.

6. The contact element as claimed in claim 2 , wherein the contact element comprises a contact glass for ophthalmic surgery with the exit side having a substantially spherical surface curvature with a radius of between about seven and about twenty five millimeters.

7. The contact element as claimed in claim 1 , wherein the contact element comprises a material whose refractive index is greater than a refractive index of the object.

8. A laser processing device comprising:
a laser emitting laser radiation and a scanning unit deflecting the laser radiation by an angle of deflection to provide scanned laser radiation;
a contact element including a plano-concave base body a concave surface of which provides an exit side, a planar surface of which provides an entrance side, wherein a diffractive optical element is formed on or at a surface of the entrance side, the exit side imparting a defined surface curvature to the surface of an object upon contact therewith, wherein the entrance side cross section is larger than a cross section of the scanned laser radiation which is deflected by the scanning unit over the entrance side;
wherein the diffractive optical element is configured to reduce the angle of incidence of the scanned laser radiation on an interface between the surface of the object and the exit side of the contact element peripheral to an optical axis, the angle of incidence being measured from a normal to the defined surface curvature on the surface of the object across the exit side that imparts the defined surface curvature to the surface of the object; focusing optics arranged preceding the contact element, said focusing optics focusing the scanned laser radiation into focal points located in the object; wherein the focusing optics comprise a dispersive lens increasing the angle of deflection and a second diffractive optical element gathering the bundles coming from the dispersive lens.

9. The laser processing device as claimed in claim 8 , wherein the second diffractive optical element is provided on a plane-parallel plate.

10. The laser processing device as claimed in claim 8 , wherein the exit side of the contact element has a radius of surface curvature of about ten millimeters, an image field that has a diameter of about eleven millimeters, and a numerical aperture of the focusing optics that is about 0.37.

11. A laser processing device comprising:
means for generating scanned laser radiation;
a contact element including a plano-concave body a concave surface of which provides an exit side and a planar surface of which provides an entrance side, the exit side imparting a defined surface curvature to the surface of an object upon contact therewith;
means for diffractive reduction of an angle of incidence of the laser radiation on an interface between the surface of the object and the exit side of the contact element peripheral to an optical axis, the angle of incidence being measured from a normal to the defined surface curvature on the surface of the object across the exit side that imparts the defined surface curvature to the surface of the object;
means for focusing bundles of the laser radiation into focal points located in the object; wherein the means for focusing comprises means for increasing the angle of deflection and means for diffractive gathering of the bundles coming from the means for increasing the angle of deflection; and
wherein the means for generating scanned laser radiation scans the scanned laser radiation over the means for diffractive gathering.

12. The laser processing device as claimed in claim 11 , wherein means for diffractive gathering is provided on a plane-parallel plate.

13. The laser processing device as claimed in claim 11 , wherein the means for imparting a defined surface curvature has a radius of surface curvature of about ten millimeters, an image field has a diameter of about eleven millimeters, and a numerical aperture of the means for focusing about 0.37.

Assignees

• Dobschal Hans-Jürgen
• Hanft Marco
• Gerlach Mario
• Zeiss Carl Meditec Ag

Inventors

• Dobschal Hans-Jürgen
• Hanft Marco
• Gerlach Mario

Classifications

• A61F9/009 Primary

  Auxiliary devices making contact with the eyeball and coupling in laser light, {e.g. goniolenses (apparatus for eye examination A61B3/0008)} · CPC title

• A61F2009/00872

  Cornea · CPC title

• A61F9/00825

  for photodisruption · CPC title