Solid-state imaging element and imaging device
To improve detection efficiency in a solid-state imaging element including a SPAD in which an electrode and wiring are placed in a central portion. A solid-state imaging element includes a photodiode and a light collecting section. The photodiode includes a light receiving surface and an electrode placed on the light receiving surface, and that outputs an electrical signal in accordance with light incident on the light receiving surface in a state where a voltage exceeding a breakdown voltage is applied to the electrode. The light collecting section causes light from a subject to be collected in the light receiving surface other than a region where the electrode is placed.
1. A solid-state imaging element comprising:
a photodiode that includes a light receiving surface and an electrode placed on the light receiving surface, and that outputs an electrical signal in accordance with light incident on the light receiving surface in a state where a voltage exceeding a breakdown voltage is applied to the electrode; and
a light collecting section that causes light from a subject to be collected in the light receiving surface other than a region where the electrode is placed.
2. The solid-state imaging element according to claim 1 , wherein, in the photodiode, the electrode is placed substantially at a center of the light receiving surface.
3. The solid-state imaging element according to claim 1 , wherein the light collecting section includes a microlens having a concavity in a substantially central portion.
4. The solid-state imaging element according to claim 3 , wherein the microlens has an opening in the concavity.
5. The solid-state imaging element according to claim 3 , further comprising:
wiring that is electrically connected the electrode,
wherein the microlens has a concavity continuing along the wiring.
6. The solid-state imaging element according to claim 5 , wherein the microlens has a cut in a bottom portion of the continuing concavity.
7. The solid-state imaging element according to claim 1 , wherein the light collecting section includes a plurality of microlenses each of which is configured to cause light to be collected in the light receiving surface other than a region where the electrode is placed.
8. The solid-state imaging element according to claim 7 , further comprising:
wiring that is placed between the plurality of microlenses adjacent to each other, and that is electrically connected to the electrode.
9. The solid-state imaging element according to claim 7 , wherein each of the plurality of microlenses has a quadrangular bottom surface.
10. The solid-state imaging element according to claim 1 , wherein the light collecting section includes a first light collecting member and a second light collecting member that are sequentially arranged between the electrode and the subject, the second light collecting member having a larger refractive index than the first light collecting member.
11. An imaging device comprising:
a pixel circuit in which pixels each of which includes a photodiode and a light collecting section are arranged in a two-dimensional array form, the photodiode including a light receiving surface and an electrode placed on the light receiving surface, and outputting an electrical signal in accordance with light incident on the light receiving surface in a state where a voltage exceeding a breakdown voltage is applied to the electrode, the light collecting section causing light from a subject to be collected in the light receiving surface other than a region where the electrode is placed; and
a processing circuit that processes the output electrical signal.