Wire grid polarization plate having dielectric layer with concave portions
Provided is a wire grid polarization plate that has heat resistance and excellent polarization properties, and has durability even in a thin wire structure with a small pitch, and an optical apparatus and a manufacturing method of a polarization plate. A periodic lamellar structure is formed with a material forming arrangement by self-assembling performance, and then, is metallized, and thus, metal wires arranged at a small pitch are prepared, and the obtained wires are fixed by a dielectric material.
1. A polarization plate having a wire grid structure, the polarization plate comprising:
a transparent substrate; and
an array including a plurality of grid-shaped convex portions that are arranged on the transparent substrate at a pitch of greater than or equal to 30 nm and less than or equal to 100 nm and extend in a predetermined direction,
wherein the plurality of grid-shaped convex portions include at least a reflection layer, and have an aspect ratio of greater than or equal to 3 and less than or equal to 15,
a gap between the adjacent convex portions among the plurality of grid-shaped convex portions is filled with a dielectric material,
the array is fixed in a dielectric layer containing the dielectric material, and
the dielectric layer has, on a surface facing away from the transparent substrate, a plurality of concave portions extending approximately parallel to the predetermined direction in which the plurality of grid-shaped convex portions extend,
wherein a respective concave portion among the plurality of concave portions has a width approximately the same as that of the convex portion, and
wherein the respective concave portion has a depth of 10 nm to 50 nm.
2. The polarization plate according to claim 1 ,
wherein a gas layer extending in a predetermined direction is provided in the dielectric material in the gap between the adjacent convex portions.
3. The polarization plate according to claim 1 , further comprising:
an antireflection layer on the dielectric layer.
4. The polarization plate according to claim 1 ,
wherein the convex portion further includes a dielectric absorption layer on the reflection layer.
5. The polarization plate according to claim 1 ,
wherein a surface of the polarization plate on which incident light enters is covered with a protective film containing a dielectric.
6. The polarization plate according to claim 1 ,
wherein a surface of the polarization plate on which incident light enters is covered with an organic water-repellent film.
7. An optical apparatus, comprising:
the polarization plate according to claim 1 .
8. A manufacturing method of the polarization plate according to claim 1 , the method comprising:
a block copolymer arranging step of allowing a block copolymer forming arrangement by self-assembling performance to be self-assembled on a reflection layer of a laminate including a transparent substrate and the reflection layer, and of forming a periodic lamellar structure;
a mask forming step of forming a mask including a plurality of grid-shaped convex portions that are arranged at a pitch of greater than or equal to 30 nm and less than or equal to 100 nm and extend in a predetermined direction, by selectively removing a specific polymer block chain of the arranged block copolymer;
an array forming step of forming an array including a plurality of grid-shaped convex portions that include at least a reflection layer, are arranged at a pitch of greater than or equal to 30 nm and less than or equal to 100 nm, and extend in a predetermined direction, by performing etching with the mask; and
a convex portion fixing step of fixing the array including the convex portions that include at least the reflection layer, in a dielectric layer containing a dielectric material.