Solid-state imaging element and imaging apparatus
The present technology relates to a solid-state imaging element and an imaging apparatus that provides an ample dynamic range. The solid-state imaging element includes a pixel array section and a readout load section. The pixel array section has a readout pixel and a reference pixel. A pixel signal proportional to an amount of incident light is read out from the readout pixel. The reference pixel has characteristics similar to those of the readout pixel. The readout load section forms a differential amplification circuit together with the readout pixel and the reference pixel and inputs, to the reference pixel, a pseudo-dark current signal corresponding to a dark current signal that occurs in the readout pixel, thus canceling the dark current signal. The present technology is applicable to a CMOS image sensor.
1. A solid-state imaging element comprising:
a pixel array section having a readout pixel from which a pixel signal proportional to an amount of incident light is read out and a reference pixel having characteristics similar to those of the readout pixel; and
a readout load section that forms a differential amplification circuit together with the readout pixel and the reference pixel and that inputs, to the reference pixel, a pseudo-dark current signal corresponding to a dark current signal that occurs in the readout pixel so as to cancel the dark current signal.
2. The solid-state imaging element of claim 1 , wherein
the readout pixel and the reference pixel are used to form a differential pair of the differential amplification circuit.
3. The solid-state imaging element of claim 1 , wherein
the reference pixel is provided on a positive input side of the differential amplification circuit and the readout pixel is provided on a negative input side of the differential amplification circuit.
4. The solid-state imaging element of claim 1 , wherein
the reference pixel includes a dummy pixel located outside an effective region where the readout pixel is provided.
5. The solid-state imaging element of claim 4 , wherein
a light-receiving surface of the dummy pixel is shielded from light.
6. The solid-state imaging element of claim 1 , wherein, when the pixel signal is read out from the readout pixel, another readout pixel whose pixel signal readout has already been completed is used as the reference pixel.
7. The solid-state imaging element of claim 1 , further comprising:
a pseudo-signal generation section adapted to generate the pseudo-dark current signal on a basis of a pixel signal read out from a light-shielded pixel having characteristics equivalent to those of the readout pixel and whose light-receiving surface is shielded from light.
8. The solid-state imaging element of claim 7 , wherein
the pseudo-dark current signal includes an analog voltage signal or an analog current signal.
9. The solid-state imaging element of claim 1 , wherein the pixel signal of the readout pixel is generated on a basis of a reset level of the readout pixel that includes a pseudo-dark current signal component and a signal level of the readout pixel that does not include the pseudo-dark current signal component but includes a dark current signal component.
10. The solid-state imaging element of claim 1 , wherein the pixel signal of the readout pixel is generated on a basis of a reset level of the readout pixel that does not include a pseudo-dark current signal component and a signal level of the readout pixel that includes the pseudo-dark current signal component and a dark current signal component.
11. The solid-state imaging element of claim 1 , wherein
the solid-state imaging element includes a back-illuminated imaging element.
12. The solid-state imaging element of claim 11 , wherein
the solid-state imaging element includes:
a first substrate on which the pixel array section is formed; and
a second substrate on which pixel peripheral circuits including the readout load section are formed.
13. An imaging apparatus comprising:
a pixel array section having a readout pixel from which a pixel signal proportional to an amount of incident light is read out and a reference pixel having characteristics similar to those of the readout pixel; and
a readout load section that forms a differential amplification circuit together with the readout pixel and the reference pixel and that inputs, to the reference pixel, a pseudo-dark current signal corresponding to a dark current signal that occurs in the readout pixel so as to cancel the dark current signal.