Solid-state image pickup device
This invention is a solid-state image pickup device that solves the problem of limited dynamic range in the high luminance region in an image sensor having white pixels. White pixels or yellow pixels and at least red pixels, green pixels or blue pixels are arranged in array form on the light receiving surface of a semiconductor substrate. White pixels or yellow pixels have an additional capacitance C S connected to the photodiode via the floating diffusion, a capacitance coupling transistor S that can couple or separate the floating diffusion and the additional capacitance. The proportion of white or yellow pixels to the total number of pixels is higher in a central portion of the light receiving surface than a peripheral portion. The white or yellow pixel may share a floating diffusion with a red, green or blue pixel.
1. A solid-state image pickup device comprising:
a light receiving surface of a semiconductor substrate having an array of pixels, said array of pixels including white pixels having no color filter and red, green and blue pixels having corresponding red, green and blue color filters;
said white pixels include:
a photodiode generating and accumulating photocharges corresponding to received light,
a floating diffusion,
a transfer transistor having a source-drain path connected between said photodiode and said floating diffusion and a gate receiving a transfer drive signal, said transfer transistor selectively coupling said photodiode and said floating diffusion to transfer photocharges from said photodiode to said floating diffusion or isolating said photodiode and said floating diffusion dependent upon a digital state of said transfer drive signal,
an additional capacitance,
a capacitance-coupling transistor having a source-drain path connected between said floating diffusion and said additional capacitance and a gate receiving a capacitance-coupling drive signal, said capacitance-coupling transistor selectively coupling said floating diffusion to said additional capacitance to share charge or isolating said floating diffusion from said additional capacitance dependent upon a digital state of said capacitance-coupling drive signal.
2. The solid-state image pickup device of claim 1 , wherein:
said red, green and blue pixels each include:
a second photodiode generating and accumulating photocharges corresponding to received light,
a second floating diffusion,
a second transfer transistor having a source-drain path connected between said photodiode and said floating diffusion and a gate receiving a second transfer drive signal, said second transfer transistor selectively coupling said second photodiode and said second floating diffusion to transfer photocharges from said second photodiode to said second floating diffusion or isolating said second photodiode and said second floating diffusion dependent upon a digital state of said second transfer drive signal,
a second additional capacitance,
a second capacitance-coupling transistor having a source-drain path connected between said second floating diffusion and said second additional capacitance and a gate receiving said capacitance-coupling drive signal, said capacitance-coupling transistor selectively coupling said second floating diffusion to said second additional capacitance to share charge or isolating said second floating diffusion from said second additional capacitance dependent upon a digital state of said capacitance-coupling drive signal.
3. The solid-state image pickup device of claim 2 , wherein:
said additional capacitance of said white pixels include a larger capacitance than said second additional capacitance of said red, green and blue pixels.
4. The solid-state image pickup device of claim 1 , wherein:
said light receiving surface includes a central area and a peripheral area, a proportion of said white pixels to all pixels in said peripheral area is higher than a proportion of said white pixels to all pixels in said central area.
5. A solid-state image pickup device comprising:
a light receiving surface of a semiconductor substrate having an array of pixels, said array of pixels including white pixels having no color filter and red, green and blue pixels having corresponding red, green and blue color filters;
said white pixels include:
a first photodiode generating and accumulating photocharges corresponding to received light,
a floating diffusion,
a first transfer transistor having a source-drain path connected between said photodiode and said floating diffusion and a gate receiving a first transfer drive signal, said transfer transistor selectively coupling said photodiode and said floating diffusion to transfer photocharges from said photodiode to said floating diffusion or isolating said photodiode and said floating diffusion dependent upon a digital state of said first transfer drive signal,
an additional capacitance,
a capacitance-coupling transistor having a source-drain path connected between said floating diffusion and said additional capacitance and a gate receiving a capacitance-coupling drive signal, said capacitance-coupling transistor selectively coupling said floating diffusion to said additional capacitance to share charge or isolating said floating diffusion from said additional capacitance dependent upon a digital state of said capacitance-coupling drive signal; and
each white pixel having a corresponding at least one red, green and blue pixels, each of said corresponding at least one red, green and blue pixels including:
a second photodiode generating and accumulating photocharges corresponding to received light,
a second transfer transistor having a source-drain path connected between said second photodiode and said floating diffusion and a gate receiving a second transfer drive signal, said second transfer transistor selectively coupling said second photodiode and said floating diffusion to transfer photocharges from said second photodiode to said floating diffusion or isolating said second photodiode and said floating diffusion dependent upon a digital state of said second transfer drive signal.
6. A solid-state image pickup device comprising:
a light receiving surface of a semiconductor substrate having an array of pixels, said array of pixels including yellow pixels having a yellow color filter and red, green and blue pixels having corresponding red, green and blue color filters;
said yellow pixels include:
a photodiode generating and accumulating photocharges corresponding to received light,
a floating diffusion,
a transfer transistor having a source-drain path connected between said photodiode and said floating diffusion and a gate receiving a transfer drive signal, said transfer transistor selectively coupling said photodiode and said floating diffusion to transfer photocharges from said photodiode to said floating diffusion or isolating said photodiode and said floating diffusion dependent upon a digital state of said transfer drive signal,
an additional capacitance,
a capacitance-coupling transistor having a source-drain path connected between said floating diffusion and said additional capacitance and a gate receiving a capacitance-coupling drive signal, said capacitance-coupling transistor selectively coupling said floating diffusion to said additional capacitance to share charge or isolating said floating diffusion from said additional capacitance dependent upon a digital state of said capacitance-coupling drive signal.
7. The solid-state image pickup device of claim 6 , wherein:
said red, green and blue pixels each include:
a second photodiode generating and accumulating photocharges corresponding to received light,
a second floating diffusion,
a second transfer transistor having a source-drain path connected between said photodiode and said floating diffusion and a gate receiving a second transfer drive signal, said second transfer transistor selectively coupling said second photodiode and said second floating diffusion to transfer photocharges from said second photodiode to said second floating diffusion or isolating said second photodiode and said second floating diffusion dependent upon a digital state of said second transfer drive signal,
a second additional capacitance,
a second capacitance-coupling transistor having a source-drain path connected between said second floating diffusion and said second additional capacitance and a gate receiving said capacitance-coupling drive signal, said capacitance-coupling transistor selectively coupling said second floating diffusion to said second additional capacitance to share charge or isolating said second floating diffusion from said second additional capacitance dependent upon a digital state of said capacitance-coupling drive signal.
8. The solid-state image pickup device of claim 7 , wherein:
said additional capacitance of said yellow pixels include a larger capacitance than said second additional capacitance of said red, green and blue pixels.
9. The solid-state image pickup device of claim 6 , wherein:
said light receiving surface includes a central area and a peripheral area, a proportion of said yellow pixels to all pixels in said peripheral area is higher than a proportion of said yellow pixels to all pixels in said central area.
10. A solid-state image pickup device comprising:
a light receiving surface of a semiconductor substrate having an array of pixels, said array of pixels including yellow pixels having a yellow color filter and red, green and blue pixels having corresponding red, green and blue color filters;
said yellow pixels include:
a first photodiode generating and accumulating photocharges corresponding to received light,
a floating diffusion,
a first transfer transistor having a source-drain path connected between said photodiode and said floating diffusion and a gate receiving a first transfer drive signal, said transfer transistor selectively coupling said photodiode and said floating diffusion to transfer photocharges from said photodiode to said floating diffusion or isolating said photodiode and said floating diffusion dependent upon a digital state of said first transfer drive signal,
an additional capacitance,
a capacitance-coupling transistor having a source-drain path connected between said floating diffusion and said additional capacitance and a gate receiving a capacitance-coupling drive signal, said capacitance-coupling transistor selectively coupling said floating diffusion to said additional capacitance to share charge or isolating said floating diffusion from said additional capacitance dependent upon a digital state of said capacitance-coupling drive signal; and
each yellow pixel having a corresponding at least one red, green and blue pixels, each of said corresponding at least one red, green and blue pixels including:
a second photodiode generating and accumulating photocharges corresponding to received light,
a second transfer transistor having a source-drain path connected between said second photodiode and said floating diffusion and a gate receiving a second transfer drive signal, said second transfer transistor selectively coupling said second photodiode and said floating diffusion to transfer photocharges from said second photodiode to said floating diffusion or isolating said second photodiode and said floating diffusion dependent upon a digital state of said second transfer drive signal.