Solid-state imaging element and imaging device

An imaging device, comprising:

• a high-sensitivity photodiode that has a first sensitivity higher than a specific sensitivity;
• a first charge storage unit;
• a high-sensitivity-side transfer transistor configured to transfer a first charge from the high-sensitivity photodiode to the first charge storage unit;
• a low-sensitivity photodiode that has a second sensitivity lower than the specific sensitivity;
• a second charge storage unit;
• a low-sensitivity-side transfer transistor configured to transfer a second charge from the low-sensitivity photodiode to the second charge storage unit;
• an amplification transistor configured to amplify a voltage of the first charge storage unit;
• a first conversion efficiency control transistor configured to open and close a first pathway between the first charge storage unit and the second charge storage unit to control a conversion efficiency of the imaging device,
• wherein the conversion efficiency corresponds to conversion of at least one the first charge or the second charge to the voltage;
• a third charge storage unit;
• a second conversion efficiency control transistor configured to open and close a second pathway between the second charge storage unit and the third charge storage unit to control the conversion efficiency;
• a select transistor;
• a driving circuit configured to:
• drive each of the high-sensitivity-side transfer transistor, the low-sensitivity-side transfer transistor, the first conversion efficiency control transistor, the second conversion efficiency control transistor, and the select transistor;
• control the high-sensitivity-side transfer transistor to transfer the first charge in a first period in which the first conversion efficiency control transistor is switched on and the second conversion efficiency control transistor is switched off;
• and
• control, based on the transfer the first charge in the first period, the select transistor to output a signal of the amplified voltage as a voltage signal;
• and
• a signal processing unit configured to execute a signal process on the voltage signal.

A solid-state imaging element, comprising:

• a high-sensitivity photodiode that has a first sensitivity higher than a specific sensitivity;
• a first charge storage unit;
• a high-sensitivity-side transfer transistor configured to transfer a first charge from the high-sensitivity photodiode to the first charge storage unit;
• a low-sensitivity photodiode that has a second sensitivity lower than the specific sensitivity;
• a second charge storage unit;
• a low-sensitivity-side transfer transistor configured to transfer a second charge from the low-sensitivity photodiode to the second charge storage unit;
• an amplification transistor configured to amplify a voltage of the first charge storage unit;
• a first conversion efficiency control transistor configured to open and close a first pathway between the first charge storage unit and the second charge storage unit to control a conversion efficiency of the solid-state imaging element,
• wherein the conversion efficiency corresponds to conversion of at least one the first charge or the second charge to the voltage;
• a third charge storage unit;
• a second conversion efficiency control transistor configured to open and close a second pathway between the second charge storage unit and the third charge storage unit to control the conversion efficiency;
• a select transistor;
• and
• a driving circuit configured to:
• drive each of the high-sensitivity-side transfer transistor, the low-sensitivity-side transfer transistor, the first conversion efficiency control transistor, the second conversion efficiency control transistor, and the select transistor;
• control the low-sensitivity-side transfer transistor to transfer the second charge in a first period in which the first conversion efficiency control transistor is switched on and the second conversion efficiency control transistor is switched off;
• and
• control the select transistor to:
• output a first signal of the amplified voltage as a first voltage signal based on the transfer of the second charge in the first period;
• and
• output a second signal of the amplified voltage as a second voltage signal, based on a third charge that overflows from the low-sensitivity photodiode, wherein
• the second voltage signal is output in a second period in which both the first conversion efficiency control transistor and the second conversion efficiency control transistor are switched on.