US 12,313,480 B2
Prism coupling systems and methods employing light-blocking members
Craig Llewellyn Barnes, North Cohocton, NY (US); Vitor Marino Schneider, Painted Post, NY (US); and Nathaniel David Wetmore, Corning, NY (US)
Assigned to CORNING INCORPORATED, Corning, NY (US)
Filed by CORNING INCORPORATED, Corning, NY (US)
Filed on Jun. 14, 2022, as Appl. No. 17/839,822.
Claims priority of provisional application 63/212,246, filed on Jun. 18, 2021.
Prior Publication US 2022/0404220 A1, Dec. 22, 2022
Int. Cl. G01L 1/24 (2006.01); G02B 7/18 (2021.01); H04N 23/55 (2023.01); H04N 23/56 (2023.01); G02B 27/56 (2006.01)
CPC G01L 1/24 (2013.01) [G02B 7/1805 (2013.01); H04N 23/55 (2023.01); H04N 23/56 (2023.01); G02B 27/56 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A prism coupling system configured to determine at least one stress characteristic in a chemically strengthened substrate having a surface and a near-surface waveguide, comprising:
a light source system that generates measurement light;
a coupling prism to provide optical coupling of the measurement light into and out of the near-surface waveguide over an optical path that comprises a low-angle region and a high-angle region;
a detector system arranged to receive the measurement light from the coupling prism to detect a mode spectrum image; and
a light-blocking member operably disposed to at least partially extend into the low-angle region without extending into the high-angle region,
wherein the mode spectrum image has a first contrast and wherein the light-blocking member is configured so that the first contrast is at least 10% greater than a second contrast of the mode spectrum image as captured without the light-blocking member, and
wherein an elevation light-blocking angle corresponding to a height of the light-blocking member is from greater than 17.4° to less than 25.3°, and the elevation light-blocking angle is measured from a tangent line tangent to the surface of the chemically strengthened substrate at a location where the optical path impinges the surface of the chemically strengthened substrate to an outer periphery of the light-blocking member further from the tangent line, and the light-blocking member extends from a location on the tangent line for the height to the outer periphery.