BACKGROUND

The present disclosure relates to a solid-state imaging device, a method of driving the solid-state imaging device, and an electronic apparatus, and particularly to a solid-state imaging device, a method of driving the solid-state imaging device, and an electronic apparatus that can improve autofocusing (AF) speed and accuracy.

A solid-state imaging device that performs AF with so-called a phase difference detection method in which an imaging pixel and a phase difference detection pixel are provided in a pixel array unit and AF is performed based on the amount of displacement between signals output from a pair of phase difference detection pixels has been known.

In some of these solid-state imaging devices, the number of phase difference detection pixels is increased and the AF accuracy is improved by providing two photoelectric conversion units in a pixel (see, for example, Japanese Patent Application Laid-open No. 2012-165070 and Japanese Patent Application Laid-open No. 2007-243744).

SUMMARY

In the phase difference detection pixel disclosed in Japanese Patent Application Laid-open No. 2012-165070, however, because the two photoelectric conversion units share one amplification transistor, it may be impossible to expose and read from the two photoelectric conversion units simultaneously, which makes AF tracking capabilities with respect to a fast-moving subject insufficient.

On the other hand, in the phase difference detection pixel disclosed in Japanese Patent Application Laid-open No. 2007-243744, by providing a charge storage unit configured to store charges for each photoelectric conversion unit, it is possible to expose and read from the two photoelectric conversion units simultaneously.

However, by providing a charge storage unit, the area of the photoelectric conversion unit decreases. As a result, the sensitivity of the phase difference detection pixel and the AF accuracy are reduced.

The present disclosure had been made in view of the above circumstances, and it is desirable to improve the AF speed and accuracy.

According to an embodiment of the present disclosure, there is provided a solid-state imaging device, including a pixel array unit in which a plurality of imaging pixels configured to generate an image, and a plurality of phase difference detection pixels configured to perform phase difference detection are arranged, each of the plurality of phase difference detection pixels including a plurality of photoelectric conversion units, a plurality of floating diffusions configured to convert charges stored in the plurality of photoelectric conversion units into voltage, and a plurality of amplification transistors configured to amplify the converted voltage in the plurality of floating diffusions.

In each of the plurality of phase difference detection pixels, at least one of the plurality of photoelectric conversion units may share the floating diffusion and the amplification transistor with at least one of the plurality of imaging pixels, which is adjacent to the phase difference detection pixel.

The phase difference detection pixel may include a first photoelectric conversion unit and a second photoelectric conversion unit, the first photoelectric conversion unit may share the floating diffusion and the amplification transistor with a first imaging pixel adjacent to the phase difference detection pixel, and the second photoelectric conversion unit may share the floating diffusion and the amplification transistor with a second imaging pixel that is different from the first imaging pixel and is adjacent to the phase difference detection pixel.

The phase difference detection pixel and the first imaging pixel may be included in one pixel sharing unit, and the second imaging pixel may be included in another pixel sharing unit.

According to an embodiment of the present disclosure, there is provided a method for driving a solid-state imaging device that includes a pixel array unit in which a plurality of imaging pixels configured to generate an image, and a plurality of phase difference detection pixels configured to perform phase difference detection are arranged, each of the plurality of phase difference detection pixels including a plurality of photoelectric conversion units, a plurality of floating diffusions configured to convert charges stored in the plurality of photoelectric conversion units into voltage, and a plurality of amplification transistors configured to amplify the converted voltage in the plurality of floating diffusions, the method including storing charges in the plurality of photoelectric conversion units, and reading signals corresponding to the charges stored in the plurality of photoelectric conversion units, by the solid-state imaging device, in the phase difference detection pixel.

According to an embodiment of the present disclosure, there is provided an electronic apparatus, including a solid-state imaging device that includes a pixel array unit in which a plurality of imaging pixels configured to generate an image, and a plurality of phase difference detection pixels configured to perform phase difference detection are arranged, each of the plurality of phase difference detection pixels including a plurality of photoelectric conversion units, a plurality of floating diffusions configured to convert charges stored in the plurality of photoelectric conversion units into voltage, and a plurality of amplification transistors configured to amplify the converted voltage in the plurality of floating diffusions.

According to an embodiment of the present disclosure, a plurality of FDs convert charges stored in the photoelectric conversion units into voltage in the phase difference detection pixel, and a plurality of amplification transistors amplify the voltage of the FDs.

According to an embodiment of the present disclosure, it is possible to improve the AF speed and accuracy.

These and other objects, features and advantages of the present disclosure will become more apparent in light of the following detailed description of best mode embodiments thereof, as illustrated in the accompanying drawings.

