Photoelectric conversion element, optical subassembly, and method for manufacturing photoelectric conversion element
A photoelectric conversion element includes a substrate including a lens-shaped convex portion and an annular concave portion surrounding the lens-shaped convex portion on a first main surface; a photoelectric conversion layer, positioned on an optical path of light passing through the lens-shaped convex portion, on a second main surface side of the substrate; and a pattern disposed on an outer peripheral side of the annular concave portion on the first main surface and disposed to interpose the lens-shaped convex portion from a first direction and a second direction intersecting the first direction.
1. A photoelectric conversion element comprising:
a substrate including a lens-shaped convex portion and an annular concave portion surrounding the lens-shaped convex portion on a first main surface;
a photoelectric conversion layer, positioned on an optical path of light passing through the lens-shaped convex portion, on a second main surface side of the substrate; and
a pattern disposed on an outer peripheral side of the annular concave portion on the first main surface and disposed to interpose the lens-shaped convex portion from a first direction and a second direction intersecting the first direction,
wherein the pattern is a groove provided on the first main surface.
2. The photoelectric conversion element of claim 1 , wherein the pattern includes:
a first portion disposed apart from the annular concave portion in the first direction, and
a second portion disposed apart from the first portion between the annular concave portion and the first portion.
3. The photoelectric conversion element of claim 2 , wherein a distance between the second portion and the annular concave portion is smaller than a distance between the first portion and the second portion.
4. The photoelectric conversion element of claim 1 , wherein the pattern is a groove provided on the first main surface, and a depth of the groove is shallower than a depth of the annular concave portion.
5. The photoelectric conversion element of claim 1 , wherein
the pattern is disposed in a concentric circle centering on a part of the lens-shaped convex portion.
6. The photoelectric conversion element of claim 1 , wherein
the substrate further includes a lens-shaped second convex portion and an annular second concave portion surrounding the lens-shaped second convex portion on the first main surface.
7. The photoelectric conversion element of claim 6 , further comprising a second pattern disposed on an outer peripheral side of the annular second concave portion on the first main surface and disposed to interpose the lens-shaped second convex portion from a third direction and a fourth direction intersecting the third direction.
8. An optical subassembly comprising:
a photoelectric conversion element comprising:
a substrate including a lens-shaped convex portion and an annular concave portion surrounding the lens-shaped convex portion on a first main surface;
a photoelectric conversion layer, positioned on an optical path of light passing through the lens-shaped convex portion, on a second main surface side of the substrate; and
a pattern disposed on an outer peripheral side of the annular concave portion on the first main surface and disposed to interpose the lens-shaped convex portion from a first direction and a second direction intersecting the first direction;
a package housing the photoelectric conversion element therein; and
an optical element housed in the package and making light incident on the photoelectric conversion element.
9. The optical subassembly of claim 8 , wherein the pattern includes:
a first portion disposed apart from the annular concave portion in the first direction, and
a second portion disposed apart from the first portion between the annular concave portion and the first portion.
10. The optical subassembly of claim 9 , wherein a distance between the second portion and the annular concave portion is smaller than a distance between the first portion and the second portion.
11. The optical subassembly of claim 8 , wherein the pattern is a groove provided on the first main surface, and a depth of the groove is shallower than a depth of the annular concave portion.
12. The optical subassembly of claim 8 , wherein
the pattern is disposed in a concentric circle centering on a part of the lens-shaped convex portion.
13. The optical subassembly of claim 8 , wherein
the substrate further includes a lens-shaped second convex portion and an annular second concave portion surrounding the lens-shaped second convex portion on the first main surface.
14. The optical subassembly of claim 13 , further comprising a second pattern disposed on an outer peripheral side of the annular second concave portion on the first main surface and disposed to interpose the lens-shaped second convex portion from a third direction and a fourth direction intersecting the third direction.
15. A method for manufacturing a photoelectric conversion element forming a lens-shaped convex portion in a first region on a first main surface of a substrate, comprising:
forming a photoelectric conversion layer positioned on an optical path of light passing through the lens-shaped convex portion on a second main surface side of the substrate;
forming a pattern to interpose the first region from a first direction and a second direction intersecting the first direction on the first main surface;
forming a mask for protecting at least a part of the pattern and the first region;
forming, after the mask is formed, an annular concave portion surrounding the first region between the first region and the pattern;
removing, after the annular concave portion is formed, the mask; and
processing, after the mask is removed, the first region into the lens-shaped convex portion by wet etching.
16. The method of claim 15 , wherein, when the pattern is formed, a first portion disposed apart from the annular concave portion in the first direction and a second portion disposed apart from the first portion between the annular concave portion and the first portion are formed.
17. The method of claim 16 , wherein, when the first region is processed into the lens-shaped convex portion by wet etching, the annular concave portion is widened to an outer peripheral side by side etching, and a distance between the second portion and the annular concave portion is smaller than a distance between the first portion and the second portion.
18. The method of claim 15 , wherein the pattern is formed by dry etching the first main surface.
19. The method of claim 15 , wherein a depth of the pattern is formed shallower than a depth of the annular concave portion.
20. The method of claim 15 , wherein the pattern is formed in a concentric circle centering on a part of the first region.