A polarizer having an external light incidence side adapted to face an external light, and a side opposite the external light incidence side and spaced from the external light incidence side in a thickness direction of the polarizer, the polarizer (10; 22; 100; 220) comprising: a base (11; 110); and a plurality of grids (12; 13; 120) on the base (11; 110), the plurality of grids (12; 13; 120) comprising a first component (12a; 13a; 120a) and a second component (12b; 13b; 120b), and having a thickness in the thickness direction of the polarizer (10; 22; 100; 220), wherein the first component (12a; 13a; 120a) comprises a dielectric material and the second component (12b; 13b; 120b) comprises a metal, and wherein the first component (12a; 13a; 120a) and the second component (12b; 13b; 120b), each have a concentration gradient in the thickness direction, wherein, in at least a portion of the said thickness of the grids (12; 13; 120), a concentration of the first component (12a; 13a; 120a) in the grids (12; 13; 120) increases along a first direction parallel to the thickness direction, and a concentration of the second component (12b; 13b; 120b) in the grids (12; 13; 120) increases along a second direction parallel to the thickness direction; the first direction being opposite to the second direction; CHARACTERISED IN THAT: the first direction extends toward the external light incidence side and the said second direction extends away from the external light incidence sidle; and the concentration of the first component (12a; 13a; 120a) of the grid (12; 13; 120) increases along the first direction from a central thickness region of the grids (12; 13; 120) to the light incidence surface and the concentration of the second component (12b; 13b; 120b) of the grids (12; 13; 120) increases along the second direction from the light incidence surface to the central region. a base (11; 110); and a plurality of grids (12; 13; 120) on the base (11; 110), the plurality of grids (12; 13; 120) comprising a first component (12a; 13a; 120a) and a second component (12b; 13b; 120b), and having a thickness in the thickness direction of the polarizer (10; 22; 100; 220), wherein the first component (12a; 13a; 120a) comprises a dielectric material and the second component (12b; 13b; 120b) comprises a metal, and wherein the first component (12a; 13a; 120a) and the second component (12b; 13b; 120b), each have a concentration gradient in the thickness direction, wherein, in at least a portion of the said thickness of the grids (12; 13; 120), a concentration of the first component (12a; 13a; 120a) in the grids (12; 13; 120) increases along a first direction parallel to the thickness direction, and a concentration of the second component (12b; 13b; 120b) in the grids (12; 13; 120) increases along a second direction parallel to the thickness direction; the first direction being opposite to the second direction; CHARACTERISED IN THAT: the first direction extends toward the external light incidence side and the said second direction extends away from the external light incidence sidle; and the concentration of the first component (12a; 13a; 120a) of the grid (12; 13; 120) increases along the first direction from a central thickness region of the grids (12; 13; 120) to the light incidence surface and the concentration of the second component (12b; 13b; 120b) of the grids (12; 13; 120) increases along the second direction from the light incidence surface to the central region. the first direction extends toward the external light incidence side and the said second direction extends away from the external light incidence sidle; and the concentration of the first component (12a; 13a; 120a) of the grid (12; 13; 120) increases along the first direction from a central thickness region of the grids (12; 13; 120) to the light incidence surface and the concentration of the second component (12b; 13b; 120b) of the grids (12; 13; 120) increases along the second direction from the light incidence surface to the central region.