US 4,289,378 AGranted

Apparatus for adjusting the focal point of an operating laser beam focused by an objective

OwnerErnst Remy, Eberhard Unsoldinventors

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Abstract

A method of and an apparatus for adjusting the focal point of a working laser beam onto a microscopic target region of a transparent biological object to locate the focal point a spaced predetermined microscopic distance from an interface of the object is described. Separate working and auxiliary laser beams are produced which are then collinearly superimposed in parallel relationship, the auxiliary laser beam having a wavelength within the visible range and different from the wavelength of the working laser beam. The superimposed laser beams are focused jointly through the objective of a microscope onto the object. First variable focusing means placed in the path of one of the laser beams is controlled to produce a spacing between the focal spots equal to the predetermined distance. A further variable focusing means in the path of both the working and laser beams is controlled to jointly move the focal spots of both beams without varying the distance therebetween until the focal spot of the auxiliary laser beam appears on the interface of the object, whereby the working laser beam is focused the predetermined distance from the interface in the object.

Claims4

Dependent claims

Apparatus for adjusting the focal spot of a working laser beam onto a microscopic target region within a transparent biological object observed under a microscope to locate that focal spot a predetermined controllable microscopic distance from an interface of said object, said apparatus comprising

(a) a microscope having an objective, an eyepiece, a support for said object and means to move said support so as to bring the target region of said object into the focusing plane of said objective;
(b) a working laser for emitting a parallel laser beam and an auxiliary laser for emitting a parallel laser beam in the visible wavelength region along separate paths;
(c) means for collinearly superimposing said two laser beams from said paths and for introducing the superimposed beams into the microscope so as to be focused jointly through said objective onto said object;
(d) first variable focusing means interposed in the path of one of said laser beams;
(e) second variable focusing means interposed in the path of said superimposed working and auxiliary laser beams, said second variable focusing means comprising a lens arrangement producing intermediate focal spots of said two laser beams and means for varying the distance of said intermediate focal spots from said microscope objective;
(f) first control means for controlling said first variable focusing means so as to produce a longitudinal spacing of predetermined distance between the focal spots produced by said objective;
and
(g) second control means for controlling said second variable focusing means independently of said first variable focusing means for moving the two focal spots jointly without varying the distance therebetween;
(h) whereby the focal spot of said auxiliary laser beam may be made to appear on an interface of said object and said working laser beam may be focused said predetermined distance from said interface.

6 more elements

(a) a microscope having an objective, an eyepiece, a support for said object and means to move said support so as to bring the target region of said object into the focusing plane of said objective;
(b) a working laser for emitting a parallel laser beam and an auxiliary laser for emitting a parallel laser beam in the visible wavelength region along separate paths;
(c) means for collinearly superimposing said two laser beams from said paths and for introducing the superimposed beams into the microscope so as to be focused jointly through said objective onto said object;
(d) first variable focusing means comprising a first lens arrangement interposed in the separate path of one of said laser beams;
(e) second variable focusing means comprising a second lens arrangement interposed in the separate path of the other of said laser beams;
(f) first control means for controlling said first variable focusing means and adapted to establish a predetermined difference in setting of said lens arrangements so as to produce a longitudinal spacing of predetermined distance between the focal spots produced by said objective;
and
(g) second control means for controlling both said first and second variable focusing means and adapted to jointly vary the setting of said two lens arrangements for moving the two focal spots jointly without varying the distance therebetween;
and
(h) whereby the focal spot of said auxiliary laser beam may be made to appear on an interface of said object and said working laser beam may be focused said predetermined distance from said interface.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/084,483Filed 15 Oct 1979 · continuation in part
Priority: 20 Dec 1974
Granted: 15 Sep 1981
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

B23K 26/02
Working by laser beam, e.g. welding, cutting or boring: positioning or observing the workpiece, e.g. with respect to the point of impact;…
G02B 21/082
Condensers: for incident illumination only
G02B 21/24
Microscopes: base structure
G02B 27/16
Beam splitting or combining systems: used as aids for focusing