US 12,032,193 B2
Optical element and method for manufacturing the same
Kenta Sekikawa, Fukushima (JP); Hiromichi Nagayama, Fukushima (JP); and So Ishido, Fukushima (JP)
Assigned to AGC Inc., Tokyo (JP)
Filed by AGC Inc., Tokyo (JP)
Filed on Feb. 1, 2023, as Appl. No. 18/162,909.
Application 18/162,909 is a continuation of application No. PCT/JP2021/028752, filed on Aug. 3, 2021.
Claims priority of application No. 2020-135092 (JP), filed on Aug. 7, 2020.
Prior Publication US 2023/0176270 A1, Jun. 8, 2023
Int. Cl. G02B 5/30 (2006.01); G02B 3/00 (2006.01)
CPC G02B 5/3091 (2013.01) [G02B 3/0018 (2013.01); G02B 5/3016 (2013.01); G02B 5/3041 (2013.01)] 7 Claims
OG exemplary drawing
 
1. An optical element comprising:
a three-dimensional structure having a curved surface; and
a retardation plate bent along the curved surface, wherein
the retardation plate includes a transparent substrate, an alignment layer formed over the transparent substrate, and a liquid crystal layer formed over the alignment layer,
the retardation plate has a slow axis and a fast axis,
the alignment layer has a plurality of grooves parallel to each other on a surface in contact with the liquid crystal layer when viewed from a direction normal to the curved surface of the three-dimensional structure at a center of gravity of the curved surface,
a depth of a groove at a position where a thickness of the retardation plate is thinnest is deeper than a depth of a groove at a position where the thickness of the retardation plate is thickest, and
a glass-transition temperature, Tgne, in a slow axis direction of the retardation plate is higher than a glass-transition temperature, Tgno, in a fast axis direction of the retardation plate.