Solid-state imaging element and electronic device
In a solid-state imaging element that measures a distance on the basis of a light receiving timing of reflected light, the shortest distance that can be measured is shortened. A photoelectric conversion region generates charges through photoelectric conversion. A multiplication region multiplies the generated charges. An output electrode outputs the multiplied charges. A detection circuit detects the presence or absence of photons contained in reflected light with respect to radiation light on the basis of the charges output from the output electrode. An additional electrode discharges the charges from the photoelectric conversion region in a case where a predetermined potential is applied to the additional electrode. A control circuit applies the predetermined potential to the additional electrode at a radiation timing when the radiation light is radiated.
1 . A solid-state imaging element, comprising:
a photoelectric conversion region configured to generate charges through photoelectric conversion;
a multiplication region configured to multiply the generated charges;
an output electrode configured to output the multiplied charges;
a detection circuit configured to detect a presence or an absence of photons contained in reflected light with respect to radiation light based on the charges output from the output electrode;
an additional electrode configured to discharge the charges from the photoelectric conversion region in a case where a specific potential is applied; and
a control circuit configured to apply the specific potential to the additional electrode at a radiation timing in a case where the radiation light is radiated,
wherein the detection circuit includes:
a current source,
a transistor in which an enable signal is input to a gate, and
a logic gate that outputs a pulse signal based on a potential of a connection node between the current source and the transistor, wherein
the current source and the transistor are connected in series between a power source node and a reference node, and
the output electrode is connected to the connection node.
2 . The solid-state imaging element according to claim 1 , wherein
the output electrode and the additional electrode are cathodes, and
the charges are electrons.
3 . The solid-state imaging element according to claim 1 , wherein the control circuit is further configured to apply the specific potential over a specific period to control the transistor to be in an on state with the enable signal over a period from a start timing of the specific period to a specific timing before an end timing of the specific period.
4 . The solid-state imaging element according to claim 1 , further comprising a signal processing unit configured to calculate a distance based on the pulse signal.
5 . The solid-state imaging element according to claim 4 , wherein the signal processing unit is further configured to:
acquire a reference distance based on the pulse signal within a specific reference distance measurement period,
calculate a distance based on the pulse signal within a specific distance measurement period, and
correct the distance based on the reference distance.
6 . The solid-state imaging element according to claim 4 , wherein
the photoelectric conversion region, the multiplication region, the output electrode, the detection circuit, and the additional electrode are in each of a reference pixel and a distance measurement pixel, and
the signal processing unit is further configured to:
acquire a reference distance based on the pulse signal from the reference pixel,
calculate a distance based on the pulse signal from the distance measurement pixel, and
correct the distance based on the reference distance.
7 . An electronic device, comprising:
a light emitting unit configured to radiate radiation light;
a photoelectric conversion region configured to generate charges through photoelectric conversion;
a multiplication region configured to multiply the generated charges;
an output electrode configured to output the multiplied charges;
a detection circuit configured to detect a presence or an absence of photons contained in reflected light with respect to the radiation light based on the charges output from the output electrode;
an additional electrode configured to discharge the charges from the photoelectric conversion region in a case where a specific potential is applied to the additional electrode; and
a control circuit configured to apply the specific potential to the additional electrode at a radiation timing in a case where the radiation light is radiated,
wherein the detection circuit includes:
a current source,
a transistor in which an enable signal is input to a gate, and
a logic gate that outputs a pulse signal based on a potential of a connection node between the current source and the transistor, wherein
the current source and the transistor are connected in series between a power source node and a reference node, and
the output electrode is connected to the connection node.
8 . A solid-state imaging element, comprising:
a pixel array unit including a plurality of pixels, wherein each of the plurality of pixels includes:
a photoelectric conversion region configured to generate charges through photoelectric conversion,
a multiplication region configured to multiply the generated charges, and
an output electrode configured to output the multiplied charges;
a detection circuit configured to detect a presence or an absence of photons contained in reflected light with respect to radiation light based on the charges output from the output electrode,
wherein the detection circuit includes:
a current source,
a transistor in which an enable signal is input to a gate, and
a logic gate that outputs a pulse signal based on a potential of a connection node between the current source and the transistor, wherein
the current source and the transistor are connected in series between a power source node and a reference node, and
the output electrode is connected to the connection node; and
an additional electrode in a region including a boundary between the plurality of pixels, wherein the additional electrode is configured to discharge the charges from the photoelectric conversion region.
9 . The solid-state imaging element according to claim 8 , wherein
the pixel array unit is divided into a plurality of sharing blocks,
each of the plurality of sharing blocks includes a specific number of pixels, and
each of the plurality of sharing blocks includes the specific number of pixels share the additional electrode.
10 . The solid-state imaging element according to claim 9 , wherein four pixels are in each of the plurality of sharing blocks.
11 . The solid-state imaging element according to claim 9 , wherein two pixels are in each of the plurality of sharing blocks.
12 . The solid-state imaging element according to claim 8 , wherein the additional electrode is for each pixel.
13 . The solid-state imaging element according to claim 8 , wherein the additional electrode is in a region including corners of the pixels in the boundary.
14 . The solid-state imaging element according to claim 8 , wherein the additional electrode is in a region not including corners of pixels of the plurality of pixels in the boundary.
15 . The solid-state imaging element according to claim 8 , wherein
the output electrode and the additional electrode are cathodes, and
each of the plurality of pixels includes an anode embedded in the boundary.
16 . The solid-state imaging element according to claim 8 , wherein
a specific semiconductor region is between the output electrode and the additional electrode, and
the output electrode and the additional electrode are formed of a semiconductor having a polarity different from that of the specific semiconductor region.
17 . An electronic device, comprising:
a light emitting unit configured to radiate radiation light;
a pixel array unit including a plurality of pixels, wherein each of which the plurality of pixels includes:
a photoelectric conversion region configured to generate charges through photoelectric conversion,
a multiplication region configured to multiply the generated charges, and
an output electrode configured to output the multiplied charges are disposed are arranged;
a detection circuit configured to detect a presence or an absence of photons contained in reflected light with respect to radiation light based on the charges output from the output electrode, wherein the detection circuit includes
a current source,
a transistor in which an enable signal is input to a gate, and
a logic gate that outputs a pulse signal based on a potential of a connection node between the current source and the transistor, wherein
the current source and the transistor are connected in series between a power source node and a reference node, and
the output electrode is connected to the connection node; and
an additional electrode in a region including a boundary between the plurality of pixels, wherein the additional electrode is configured to discharge the charges from the photoelectric conversion region.