US 11,852,460 B2
Water-immersed high precision laser focus spot size measurement apparatus
Zheng Sun, San Jose, CA (US); Daniel Bray, Milpitas, CA (US); Zenon Witowski, Pleasanton, CA (US); Timothy Slotterback, Trabuco Canyon, CA (US); and Hong Fu, Pleasanton, CA (US)
Assigned to AMO Development, LLC, Irvine, CA (US)
Filed by AMO DEVELOPMENT, LLC, Irvine, CA (US)
Filed on Jan. 20, 2023, as Appl. No. 18/157,729.
Application 17/452,035 is a division of application No. 16/907,105, filed on Jun. 19, 2020, granted, now 11,156,453, issued on Oct. 26, 2021.
Application 16/907,105 is a division of application No. 16/027,137, filed on Jul. 3, 2018, granted, now 10,690,486, issued on Jun. 23, 2020.
Application 18/157,729 is a continuation of application No. 17/452,035, filed on Oct. 22, 2021, granted, now 11,561,087.
Prior Publication US 2023/0175838 A1, Jun. 8, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G01B 11/24 (2006.01)
CPC G01B 11/2408 (2013.01) 7 Claims
OG exemplary drawing
 
1. A method for measuring a light beam focus spot size, comprising:
by an imaging system which includes at least an objective lens, forming a magnified image of a light beam focus spot on a detecting surface of a two-dimensional image detector;
by a data processing device coupled to the image detector, processing image data generated by the image detector, including:
(a) receiving image data representing the image of the light beam focus spot;
(b) calculating a centroid of the focus spot;
(c) determining whether the centroid is located at a predetermined center position;
(d) when the centroid is located at the predetermined center position, storing the image in an image buffer;
(e) when the centroid is not located at the predetermined center position, defining a region of interest (ROI) of the image containing the focus spot and extracting the ROI to a new image, the new image containing the focus spot centered at a predetermined center position of the new image, and storing the new image in the image buffer; and
(f) analyzing the images stored in the image buffer to obtain a characteristic of the light beam focus spot.