US 12,222,530 B2
Wavelength selective filter, display, optical device, and method of producing wavelength selective filter
Masashi Kawashita, Tokyo (JP); and Yukari Oda, Tokyo (JP)
Assigned to TOPPAN INC., Tokyo (JP)
Filed by TOPPAN INC., Tokyo (JP)
Filed on Dec. 21, 2021, as Appl. No. 17/557,917.
Application 17/557,917 is a continuation of application No. PCT/JP2020/025397, filed on Jun. 26, 2020.
Claims priority of application No. 2019-120103 (JP), filed on Jun. 27, 2019; and application No. 2019-120104 (JP), filed on Jun. 27, 2019.
Prior Publication US 2022/0113458 A1, Apr. 14, 2022
Int. Cl. G02B 5/26 (2006.01); H01L 27/146 (2006.01)
CPC G02B 5/26 (2013.01) [H01L 27/1462 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A wavelength selective filter, comprising:
a concavo-convex structure layer having a concavo-convex structure on a surface, the concavo-convex structure being composed of a plurality of concavo-convex elements arranged having a subwavelength period, the concavo-convex elements including protrusions and recesses;
a high refractive index layer located on the concavo-convex structure and having a surface shape following the concavo-convex structure, the high refractive index layer including a first grating high refractive index region located on a bottom of the concavo-convex structure to form a subwavelength grating, and a second grating high refractive index region located on a top of the concavo-convex structure to form a subwavelength grating; and
a low refractive index layer located on the high refractive index layer and having a surface shape following a concavo-convex structure on a surface of the high refractive index layer, wherein
the high refractive index layer has a refractive index higher than both of refractive indices of the concavo-convex structure layer and the low refractive index layer,
the concavo-convex structure layer, the high refractive index layer, and the low refractive index layer are made of a material transparent to light in a visible region,
the concavo-convex structure layer includes a UV-curable resin, a heat-curable resin, or a thermoplastic resin, and
the low refractive index layer includes an inorganic compound.