Laser beam calibration and beam quality measurement in laser surgery systems

Patent metadata

Field	Value
Publication number	US-11896526-B2
Application number	US-202016885252-A
Country	US
Kind code	B2
Filing date	May 27, 2020
Priority date	Oct 21, 2015
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A laser eye surgery system includes a computer which scans a focused laser beam in a trajectory over a reticle or target and determines beam quality via laser light reflected from the target. The target may have a grid pattern of lines, with the diameter of the focused laser beam determined based on a time interval for the scanned beam to move onto a line of the grid pattern. Methods for measuring beam quality in a laser eye surgery system provide a direct, quantitative quality measurement of the focused laser beam, and may be performed quickly and automatically. Using scanning mirror position information together with signals resulting from laser light reflected from the target, the laser eye surgery system may also be calibrated.

First claim

The invention claimed is:

1. A method for calibrating a laser eye surgery system, comprising:
a. scanning a focused laser beam in a trajectory over a target via a scanning mirror, the target having a plurality of lines;
b. sensing laser light reflected or scattered by a first line of the target at time T1 when the laser beam intersects a first edge of the first line to determine an actual laser beam position;
c. sensing a position of the scanning mirror at time T1;
d. repeating steps A-C, the laser beam intersecting subsequent lines at subsequent times;
e. generating a table of digitized actual laser beam position values versus sensed scanning mirror position values at time T1 and the subsequent times; and
f. calibrating the laser eye surgery system based at least in part on the table generated in step E.

2. The method of claim 1 further including mapping pixels on a display of the system to positions on the target.

3. The method of claim 1 , wherein the laser beam is focused via an objective lens and further including supporting the target on a holder attached to the objective lens.

4. The method of claim 1 wherein the focused laser beam is an infrared femtosecond laser beam, a visible light laser beam, or an ultraviolet laser beam.

5. A laser eye surgical system, comprising:
a laser assembly for generating a laser beam;
a sensor mirror between the laser assembly and a scanning mirror;
a sensor positioned to detect light reflected by the sensor mirror;
an objective lens between the scanning mirror and a target;
a target holder configured to support the target at a plurality of different distances from the objective lens along a propagation direction of the laser beam; and
a computer linked to the laser assembly, the sensor, the scanning mirror and the target holder;
wherein the laser assembly projects the laser beam through the sensor mirror to a scanning mirror, wherein the laser beam is reflected by the scanning mirror and projected through the objective lens and onto the target;
wherein the target has a plurality of lines reflecting laser light of the laser beam to the sensor via the objective lens, the scanning mirror and the sensor mirror, and the sensor provides a signal to the computer based on sensed light reflected from the target;
wherein the computer is configured to control the target holder to successively support the target at the plurality of different distances from the objective lens, to receive a plurality of signals from the sensor while the target is successively supported at the plurality of different distances from the objective lens, and to compare the received plurality of signals to identify a focal plane position along the propagation direction of the laser beam where the laser beam is best focused.

6. The system of claim 5 , wherein the target comprises a grid of perpendicular lines.

7. The system of claim 6 , wherein the target comprises reflective metal lines on a transparent substrate.

8. The system of claim 5 , wherein the objective lens has patient interface attachment fittings, and wherein the target is on a holder attached onto the objective lens via the patient interface attachment fittings.

9. The system of claim 5 , wherein the computer, the laser assembly, the sensor mirror, the sensor, and the scanning mirror are within an enclosure, and wherein the target and a portion of the objective lens are outside of the enclosure.

10. The system of claim 9 , wherein the laser assembly, the sensor mirror and the sensor are in fixed positions within the enclosure.

11. The system of claim 5 , wherein the laser beam has a diameter of 1-2 microns and wherein the target has lines at least 40 times wider than the beam diameter.

Assignees

• Amo Dev Llc

Inventors

• Bareket Noah
• Dewey David A
• Simoneau Michael J

Classifications

• A61F9/008 Primary

  using laser · CPC title

• A61F9/009

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

• A61F2009/00844

  Feedback systems · CPC title

• A61F2009/00855

  Calibration of the laser system · CPC title