Image sensing device and method for sensing distance
An image sensing device is provided to include a first pixel including a first single-photon avalanche diode (SPAD) that includes a cathode to receive a first bias voltage; a second pixel including a second SPAD that includes an anode to receive a second bias voltage; and a selection circuit coupled to the first pixel and the second pixel and configured to select the first pixel or the second pixel to produce an output.
1 . An image sensing device comprising:
a first pixel including a first single-photon avalanche diode (SPAD) that includes a cathode to receive a first bias voltage;
a second pixel including a second SPAD that includes an anode to receive a second bias voltage; and
a selection circuit coupled to the first pixel and the second pixel and configured to select the first pixel or the second pixel to produce an output.
2 . The image sensing device according to claim 1 , wherein the selection circuit includes:
a mode selector configured to activate the first pixel or the second pixel in response to a mode selection signal based on at least one of illuminance information, power information, user selection information, or temperature information.
3 . The image sensing device according to claim 2 , wherein:
the first pixel includes:
a first control transistor coupled between the cathode of the first SPAD and the mode selector and configured to receive a mode selection voltage in response to the mode selection signal; and
the second pixel includes:
a second control transistor coupled between the anode of the second SPAD and the mode selector and configured to receive the mode selection voltage.
4 . The image sensing device according to claim 3 , wherein:
the first control transistor is configured to be turned on, in response to the mode selection voltage being the first bias voltage, to transmit the first bias voltage to the cathode of the first SPAD.
5 . The image sensing device according to claim 3 , wherein:
the second control transistor is configured to be turned on, in response to the mode selection voltage being the second bias voltage, to transmit the second bias voltage to the anode of the second SPAD.
6 . The image sensing device according to claim 3 , wherein:
the first control transistor is a PMOS transistor; and
the second control transistor is an NMOS transistor.
7 . The image sensing device according to claim 2 , wherein:
the first pixel includes:
a first control transistor coupled between the cathode of the first SPAD and a node to which the first bias voltage is applied, and configured to receive a mode selection voltage in response to the mode selection signal; and
the second pixel includes:
a second control transistor coupled between the anode of the second SPAD and a node to which the second bias voltage is applied, and configured to receive the mode selection voltage.
8 . The image sensing device according to claim 7 , wherein the first control transistor is configured to be turned on, in response to the mode selection voltage being at a first activation voltage lower than the first bias voltage, to transmit the first bias voltage to the cathode of the first SPAD.
9 . The image sensing device according to claim 7 , wherein:
the second control transistor is configured to be turned on, in response to the mode selection voltage being at a second activation voltage higher than the second bias voltage, to transmit the second bias voltage to the anode of the second SPAD.
10 . The image sensing device according to claim 2 , wherein:
the mode selector is configured to activate the first pixel in response to the illuminance information indicating that an illuminance value is equal to or greater than a predetermined threshold value.
11 . The image sensing device according to claim 2 , wherein:
the mode selector is configured to activate the second pixel in response to the illuminance information indicating that an illuminance value is less than a predetermined threshold value.
12 . The image sensing device according to claim 1 , wherein the selection circuit includes:
an output selector configured to select an output signal of the first pixel or an output signal of the second pixel as a pixel output signal in response to a mode selection signal based on illuminance information.
13 . The image sensing device according to claim 12 , wherein:
the output selector is configured to select the output signal of the first pixel in response to the illuminance information indicating that an illuminance value is equal to or greater than a predetermined threshold value.
14 . The image sensing device according to claim 12 , wherein:
the output selector is configured to select the output signal of the second pixel in response to the illuminance information indicating that an illuminance value is less than a predetermined threshold value.
15 . The image sensing device according to claim 1 , wherein:
the first pixel and the second pixel are alternately arranged in a first direction.
16 . The image sensing device according to claim 1 , wherein:
the first pixel and the second pixel are configured to form a first block and a second block, respectively, each of the first block and the second block having a (Mx N) matrix structure,
wherein at least one of M and N is a natural number of 2 or greater,
in the first block, the first pixel is arranged to be adjacent to another first pixel, and
in the second block, the second pixel is arranged to be adjacent to another second pixel.
17 . The image sensing device according to claim 1 , wherein each of the first pixel and the second pixel includes:
a sensor layer configured to include the first SPAD or the second SPAD, and
a logic layer configured to include a circuit for driving the first SPAD or the second SPAD.
18 . The image sensing device according to claim 1 , wherein the second pixel further includes:
a first optical structure configured to increase sensitivity of the second SPAD.
19 . The image sensing device according to claim 18 , wherein the first optical structure further includes:
a plurality of uneven structures formed to scatter light incident on the second pixel.
20 . The image sensing device according to claim 1 , wherein the first pixel further includes:
a second optical structure configured to reduce sensitivity of the first SPAD.
21 . The image sensing device according to claim 1 , wherein the first pixel includes:
a first output node disposed at a center of the first pixel and corresponding to an anode of the first SPAD; and
a first biasing node disposed to surround the first output node and corresponding to the cathode of the first SPAD.
22 . The image sensing device according to claim 1 , wherein the first pixel includes:
a first P-type region disposed on a top surface of a semiconductor substrate and configured to correspond to the anode of the first SPAD; and
a first N-type region spaced apart from the first P-type region and configured to correspond to the cathode of the first SPAD.
23 . The image sensing device according to claim 1 , wherein the first pixel includes:
a first output node disposed at a center of the first pixel and corresponding to an anode of the first SPAD; and
a first biasing node disposed at each vertex of the first pixel and corresponding to the cathode of the first SPAD.
24 . The image sensing device according to claim 1 , wherein the first pixel includes:
a central biasing node disposed at a center of the first pixel and corresponding to the cathode of the first SPAD;
a first output node disposed to surround the central biasing node and corresponding to an anode of the first SPAD; and
a first biasing node disposed at each vertex of the first pixel.
25 . An image sensing device comprising:
a first pixel including a first single-photon avalanche diode (SPAD) with a first detection sensitivity;
a second pixel including a second SPAD with a second detection sensitivity higher than the first detection sensitivity; and
a selection circuit coupled to the first pixel and the second pixel and configured to select the first pixel or the second pixel to produce an output.