CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase of International Patent Application No. PCT/JP2018/022322 filed on Jun. 12, 2018, which claims priority benefit of Japanese Patent Application No. JP 2017-148821 filed in the Japan Patent Office on Aug. 1, 2017. Each of the above-referenced applications is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present technology relates to a solid-state image sensor, an imaging device, and a method of controlling a solid-state image sensor. Specifically, the present invention relates to a solid-state image sensor that outputs a pixel signal via a vertical signal line, an imaging device, and a method of controlling the same.

BACKGROUND ART

Conventionally, solid-state image sensors that photoelectrically convert light to capture image data have been used in imaging devices or the like. For example, for the purpose of increasing sensitivity, a differential amplification-type solid-state image sensor has been proposed, which amplifies a difference (that is, performs differential amplification) between respective pixel signals of a pair of pixels in a differential mode (for example, (See Non-Patent Document 1). This solid-state image sensor can change a circuit configuration in a pixel and output a pixel signal without performing the differential amplification in a non-differential mode. In the non-differential mode, the sensitivity is reduced while the readout speed is increased as compared with the differential mode. Furthermore, in the solid-state image sensor, a vertical signal line VRD for supplying a reset power supply in the differential mode and a vertical signal line VSL for outputting a pixel signal in the differential mode and the non-differential mode are wired for every column.

CITATION LIST

Non-Patent Document

Non-Patent Document 1: Jaehyuk Choi, et al., An Energy/Illumination-Adaptive CMOS Image Sensor With Reconfigurable Modes of Operations, IEEE JOURNAL OF SOLID-STATE CIRCUITS 2015.

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, the above-described conventional technology is difficult to further increase the readout speed in the non-differential mode. If the number of wired vertical signal lines VSL used for output, of the vertical signal lines VRD and VSL, is set to two per column, two rows can be simultaneously read and the readout speed can be doubled. However, the increase in the number of wired lines makes miniaturization difficult and thus is not favorable. As described above, the solid-state image sensor capable of switching the differential mode and the non-differential mode has a problem of a difficulty in increasing the readout speed in the non-differential mode.

The present technology has been devised in view of such a situation, and an object is to increase a readout speed of a pixel signal in a non-differential mode in a solid-state image sensor that performs differential amplification in a differential mode and does not perform differential amplification in the non-differential mode.

Solutions to Problems

The present technology has been made to solve the above-described problems, and the first aspect of the present technology is a solid-state image sensor and a method of controlling the same, the solid-state image sensor including: a first pixel connected to a first signal line; a second pixel connected to a second signal line; a third pixel; a fourth pixel; a connection control unit configured to sequentially perform control of connecting the first pixel to a reset power supply via a third signal line and control of connecting the second pixel to the reset power supply via a fourth signal line in a differential mode, and perform control of connecting the third pixel to the third signal line and control of connecting the fourth pixel to the fourth signal line in a non-differential mode; and a drive unit configured to output a signal obtained by amplifying a difference between respective pixel signals of the first and second pixels via one of the first and second signal lines in the differential mode, and output respective pixel signals of the first, second, third, and fourth pixels via the first, second, third, and fourth signal lines in the non-differential mode. The above configuration brings about an effect of outputting the signal obtained by amplifying the difference in the pixel signals in the differential mode, and outputting the respective pixel signals of the first, second, third, and fourth pixels in the non-differential mode.

Furthermore, in the first aspect, the connection control unit may further perform control of connecting the first and second pixels to a predetermined current source via fifth and sixth signal lines in the differential mode, and may further perform control of connecting the first and third pixels to a power supply via the fifth signal line and control of connecting the second and fourth pixels to a power supply via the sixth signal line in the non-differential mode. The above configuration brings about an effect of supplying a current via the fifth and sixth signal lines in the differential mode and supplying a current via the fifth and sixth signal lines in the non-differential mode.

Furthermore, in the first aspect, each of the first and second pixels may include a charge storage unit configured to store a charge, and a pair of reset transistors configured to initialize an amount of the stored charge, and the connection control unit may sequentially perform control of connecting one of the pair of transistors of the first pixel to the reset power supply via the third signal line and control of connecting one of the pair of transistors of the second pixel to the reset power supply via the fourth signal line in the differential mode, and may perform control of connecting the others of the respective pairs of transistors of the first and third pixels to the power supply via the fifth signal line and control of connecting the others of the respective pairs of transistors of the second and fourth pixels to the power supply via the sixth signal line in the non-differential mode. The above configuration brings about an effect of driving the different reset transistors in the differential mode and in the non-differential mode.

Furthermore, in the first aspect, the first, second, third, and fourth signal lines may be wired along a perpendicular direction to a predetermined direction, the first and second pixels may be arrayed in the predetermined direction, the first and third pixels may be arrayed in the perpendicular direction, and the third and fourth pixels may be arrayed in the predetermined direction. The above configuration brings about an effect of outputting the signals from the pixels of 2 rows×2 columns.

Furthermore, in the first aspect, the first, second, third, and fourth signal lines may be wired along a perpendicular direction to a predetermined direction, and the first, second, third, and fourth pixels may be arrayed in the predetermined direction. The above configuration brings about an effect of outputting the signals from the pixels of 1 row×4 columns.

Furthermore, in the first aspect, the first, second, third, and fourth signal lines may be wired along a perpendicular direction to a predetermined direction, and the first, second, third, and fourth pixels may be arrayed in the perpendicular direction. The above configuration brings about an effect of outputting the signals from the pixels of 4 rows×1 column.

Furthermore, in the first aspect, each of the first, second, third, and fourth pixels may include a charge storage unit configured to store a charge, a plurality of photoelectric conversion elements each configured to photoelectrically convert incident light to generate the charge, and a transfer unit configured to transfer the charge from each of the plurality of photoelectric conversion elements to the charge storage unit. The above configuration brings about an effect of outputting the signals from the plurality of pixels sharing the charge storage unit.

Furthermore, in the first aspect, each of the first, second, third, and fourth pixels may include a microlens configured to collect incident light, a photoelectric conversion layer configured to photoelectrically convert the collected incident light to generate a charge, and a wiring layer arranged between the photoelectric conversion layer and the microlens, and the first, second, third, and fourth signal lines may be wired in the wiring layer. The above configuration brings about an effect of outputting a signal from a front surface irradiation-type solid-state image sensor.

Furthermore, in the first aspect, each of the first, second, third, and fourth pixels may include a microlens configured to collect incident light, a wiring layer, and a photoelectric conversion layer arranged between the microlens and the wiring layer and configured to photoelectrically convert the collected incident light to generate a charge, and the first, second, third, and fourth signal lines may be wired in the wiring layer. The above configuration brings about an effect of outputting a signal from a back surface irradiation-type solid-state image sensor.

Furthermore, in the first aspect, the first, second, third, and fourth pixels and the connection control unit may be arranged in a first semiconductor chip, and the drive unit may be arranged in a second semiconductor chip stacked on the first semiconductor chip. The above configuration brings about an effect of outputting a signal from a stacked-type solid-state image sensor.

Furthermore, in the first aspect, the first, second, third, and fourth pixels may be arranged in a first semiconductor chip, and the connection control unit and the drive unit may be arranged in a second semiconductor chip stacked on the first semiconductor chip. The above configuration brings about an effect of outputting a signal from a stacked-type solid-state image sensor in which only pixels are arranged in the first semiconductor chip.

Furthermore, in the first aspect, an analog-to-digital conversion unit configured to execute sampling processing of converting the pixel signal into a digital signal every time the pixel signal is output over a plurality of times, and an adder circuit configured to add and output the digital signals may be further included. The above configuration brings about an effect of outputting an added result of execution of the sampling processing over a plurality of times.

Furthermore, the second aspect of the present technology is an imaging device including a first pixel connected to a first signal line; a second pixel connected to a second signal line; a third pixel; a fourth pixel; a connection control unit configured to sequentially perform control of connecting the first pixel to a reset power supply via a third signal line and control of connecting the second pixel to the reset power supply via a fourth signal line in a differential mode, and perform control of connecting the third pixel to the third signal line and control of connecting the fourth pixel to the fourth signal line in a non-differential mode; a drive unit configured to output a signal obtained by amplifying a difference between respective pixel signals of the first and second pixels via one of the first and second signal lines in the differential mode, and output respective pixel signals of the first, second, third, and fourth pixels via the first, second, third, and fourth signal lines in the non-differential mode; and an image processing unit configured to execute predetermined processing for image data generated from the pixel signals. The above configuration brings about an effect of processing image data generated from the signal obtained by amplifying the difference in the pixel signals in the differential mode, and processing image data generated from the respective pixel signals of the first, second, third, and fourth pixels in the non-differential mode.

Effects of the Invention

According to the present technology, an excellent effect of increasing a readout speed of a pixel signal in a non-differential mode can be exhibited in a solid-state image sensor that performs differential amplification in a differential mode and does not perform differential amplification in the non-differential mode. Note that effects described here are not necessarily limited, and any of effects described in the present disclosure may be exhibited.

