Light shielding sheet
A light shielding sheet for a lens is provided, including: a metal substrate, including: a first surface; a second surface opposing the first surface; a first through light hole being in communication with the first surface and having hole radiuses gradually decreasing in a direction from the first surface to the second surface, a ratio of a depth of the first through light hole to a difference between two of the hole radiuses at two ends of the first through light hole being less than or equal to 0.5; and a second through light hole being in communication with the first through light hole and the second surface; and a light extinction film covering the first surface, the second surface, a hole wall of the first through light hole and a portion of a hole wall of the second through light hole of the metal substrate.
1. A light shielding sheet for a lens, comprising:
a metal substrate, including:
a first surface;
a second surface opposing the first surface;
a first through light hole being in communication with the first surface and having hole radiuses gradually decreasing in a direction from the first surface to the second surface, a ratio of a depth of the first through light hole to a difference between two of the hole radiuses at two ends of the first through light hole being less than or equal to 0.5; and
a second through light hole being in communication with the first through light hole and the second surface; and
a light extinction film covering the first surface, the second surface, a hole wall of the first through light hole and a portion of a hole wall of the second through light hole of the metal substrate, wherein the light extinction film includes an anti-reflection film and a light absorption film disposed between the anti-reflection film and the metal substrate, wherein the light absorption film is made of at least one selected from the group consisting of metal, metal nitride, metal hydrogen, metal oxide, a semiconductor element, semiconductor element nitride, semiconductor element hydrogen and semiconductor element hydroxide, wherein the anti-reflection film includes a Si: H layer, a SiO 2 layer and a Ti layer having different refractive indexes and stacked on one another in a high refractive index-low refractive index interaction.
2. The light shielding sheet of claim 1 , wherein the hole wall of the first through hole is an annular inclined plane.
3. The light shielding sheet of claim 1 , wherein the hole wall of the first through hole is an annular concave plane.
4. The light shielding sheet of claim 1 , wherein the light absorption film has a plurality of layers having different refractive indexes and stacked on one another in a high refractive index-low refractive index interaction.
5. The light shielding sheet of claim 1 , wherein the metal is Ti or Cr.
6. The light shielding sheet of claim 1 , wherein the semiconductor element is Si or Ge.
7. The light shielding sheet of claim 1 , wherein the light absorption film includes a Ti layer and the light absorption film has a refractive index of 1.7 to 2.5 for a wavelength of 400 to 700 nm and an absorption index less than 3.6.
8. The light shielding sheet of claim 1 , wherein the Si: H layer has a refractive index of 4.7 to 5.2 for a wavelength of 400 nm to 700 nm and an absorption index less than 2, the SiO 2 layer has a refractive index of 1.46 to 1.51 and an absorption index less than 2, and the Ti layer has a refractive index of 1.85 to 4.1 and an absorption index less than 3.4.
9. The light shielding sheet of claim 1 , wherein the light absorption film includes a Ti layer and a Si: H layer, and wherein the Si: H layer has a total thickness less than a half of a total thickness of the Ti layer.
10. The light shielding sheet of claim 1 , wherein the light absorption film includes a SiO 2 layer and a Si: H layer, and wherein the Si: H layer has a total thickness less than a half of a total thickness of the SiO 2 layer.
11. The light shielding sheet of claim 1 , wherein the light extinction film has an average reflective index less than 0.15% for a wavelength of 400 nm to 700 nm.
12. The light shielding sheet of claim 1 , wherein the light extinction film has a total thickness less than 500 nm.
13. The light shielding sheet of claim 1 , wherein an exposed portion of the hole wall of the second through light hole exposed from the light extinction film has a width less than 5 μm in a direction extending from an axis of the second through light hole.
14. The light shielding sheet of claim 13 , wherein the width of the exposed portion of the hole wall of the second through light hole in the direction extending from the axis of the second through light hole is less than 3 μm.
15. The light shielding sheet of claim 1 , wherein the metal substrate is made of one selected from the group consisting of iron, copper, aluminum, silver and gold.
16. The light shielding sheet of claim 1 , wherein the light extinction film has a chromaticity coordinate, in which 0<L*<1.4, |a*|<1, and −2.5<b*<0.