US 12,449,374 B2
Glass inspection
Simon Cherry, Wigan (GB); Ian Ross Williams, Wigan (GB); and Andrew Thomson, Newton-le-Willows (GB)
Assigned to Pilkington Group Limited, Lathom (GB)
Appl. No. 18/262,212
Filed by Pilkington Group Limited, Lathom (GB)
PCT Filed Jan. 21, 2022, PCT No. PCT/GB2022/050171
§ 371(c)(1), (2) Date Jul. 20, 2023,
PCT Pub. No. WO2022/157505, PCT Pub. Date Jul. 28, 2022.
Claims priority of application No. 2100905 (GB), filed on Jan. 22, 2021.
Prior Publication US 2024/0085342 A1, Mar. 14, 2024
Int. Cl. G01N 21/896 (2006.01); G01N 21/88 (2006.01); G01N 21/89 (2006.01)
CPC G01N 21/896 (2013.01) [G01N 21/8806 (2013.01); G01N 21/8851 (2013.01); G01N 21/8901 (2013.01); G01N 2021/8809 (2013.01); G01N 2021/8835 (2013.01); G01N 2021/8867 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of detecting a defect in a sheet of glass, the sheet of glass having a first major surface and a second opposing major surface, the method comprising the steps:
(i) directing a beam from a source of illumination onto the first major surface of the sheet of glass to illuminate the defect in the sheet of glass, the beam that strikes the first major surface of the sheet of glass being a converging beam having a first focal point;
(ii) focusing an image capture device onto a first plane to image the defect in the sheet of glass, the image capture device being at a first position relative to the defect;
(iii) using the image capture device to capture a first image of the defect, the first image comprising a first portion from the illuminated defect and a second portion due to reflection of at least a portion of the beam from the first major surface of the sheet of glass;
(iv) carrying out an adjustment step;
(v) using the image capture device to capture a second image of the defect, the second image comprising a first portion from the illuminated defect and a second portion due to reflection of at least a portion of the beam from the first major surface of the sheet of glass;
wherein in the first image of the defect the first portion is brighter than the second portion, and in the second image of the defect the first portion is darker than the second portion.