Solid-state imaging device operable in wide dynamic range

A solid-state imaging device comprising:

• an imaging portion for photoelectrically converting incident light to thereby produce “n” sorts (symbol “n” being an integer larger than, or equal to 2) of signal charges having different sensitivities, said imaging portion having at least one vertical transfer register for transferring said signal charges;
• a horizontal transfer register arranged adjacent to said imaging portion, for receiving signal charges from said at least one vertical transfer register and for independently transferring said signal charges to an output gate for clipping said signal charge of the highest sensitivity at a terminal portion thereof, for transferring said “n” sorts of signal charges having said different sensitivities in a point sequential manner;
• a charge detecting portion arranged adjacent to said output gate, for detecting said signal charges transferred from said output gate;
• a bias applying circuit for applying a bias voltage to said output gate so as to set a clip level for clipping said signal charge of said high sensitivity;
• and
• adding means for adding said signal charge of said high sensitivity to said signal charge of said low sensitivity in said charge detecting portion.

A solid-state imaging device comprising:

• an imaging portion for photoelectrically converting incident light to thereby produce a signal charge of a high sensitivity and a signal charge of a low sensitivity lower than said high sensitivity, said imaging portion having at least one vertical transfer register for transferring said signal charges;
• a horizontal transfer register arranged adjacent to said imaging portion, for receiving signal charges from said at least one vertical transfer register and for independently transferring said high sensitivity and low sensitivity signal charges to an output gate at a terminal portion thereof, which clips said signal charge of said high sensitivity;
• a charge detecting portion arranged adjacent to said output gate, for detecting said signal charges transferred from said output gate;
• and
• a bias applying circuit for applying a bias voltage used to drive said horizontal transfer register to said output gate so as to set a clip level for clipping said signal charge of said high sensitivity.

A method for solid-state imaging comprising the steps of:

• photoelectrically converting incident light to produce a signal charge of a high sensitivity;
• photoelectrically converting incident light to produce a signal charge of a low sensitivity lower than said high sensitivity;
• transferring said high sensitivity and low sensitivity signal charges along a vertical transfer register to a horizontal transfer register;
• independently transferring said high sensitivity and low sensitivity signal charges from said vertical transfer register to an output gate terminal along said horizontal transfer register;
• clipping said high sensitivity signal charges at said output gate terminal;
• detecting said signal charges transferred from said output gate;
• and
• applying a bias voltage to said output gate so as to set a clip level for clipping said high sensitivity signal charge.