Solid-state imaging device and electronic apparatus

1. A solid-state imaging device comprising:

an R pixel provided with an R filter for transmitting red-color light;

a B pixel provided with a B filter for transmitting blue-color light;

an S 1 pixel which is provided with an S 1 filter with a visible light transmittance independent of wavelengths in a visible light region across red, green and blue wavelengths and has a sensitivity higher than that of said R pixel; and

an S 2 pixel which is provided with an S 2 filter with a visible light transmittance independent of wavelengths in said visible light region across red, green and blue wavelengths and a transmittance that is lower than the visible light transmittance of said S 1 filter and has a sensitivity lower than the sensitivity of said S 1 pixel, and further wherein filters for the S 1 and S 2 pixels alone determine a relative sensitivity for these pixels.

2. The solid-state imaging device according to claim 1 wherein the sensitivity of said S 1 pixel has a value in the range 40 to 100 on the assumption that the sensitivity of a pixel having no filter is 100.

3. The solid-state imaging device according to claim 1 wherein the sensitivity of said S 2 pixel is not greater than 60 on the assumption that the sensitivity of a pixel having no filter is 100.

4. The solid-state imaging device according to claim 1 wherein the sensitivity of said S 2 pixel is set at a value lower than the higher sensitivity of the sensitivities of said R and B pixels.

5. The solid-state imaging device according to claim 1 wherein:

an image luminance signal is generated by making use of signals output from said S 1 and S 2 pixels; and

one image is generated by synthesizing said image luminance signal generated from said S 1 pixel with said image luminance signal generated from said S 2 pixel.

6. The solid-state imaging device according to claim 1 wherein:

an image luminance signal is generated by making use of signals output by said R, B, S 1 and S 2 pixels; and

a green signal is generated by making use of a ratio of said signal output by said S 1 pixel to a signal output by a pixel having a filter absorbing no light in a visible light region.

7. The solid-state imaging device according to claim 1 , wherein a pixel signal saturation determination for the S 1 pixels determines which pixels are used for generating the image data.

8. The solid-state imaging device according to claim 1 , wherein a green pixel signal is generated based on levels of a corresponding S 1 or S 2 pixel and R and B pixel data.

9. An electronic apparatus employing:

a solid-state imaging device comprising

an R pixel provided with an R filter for transmitting red-color light;

a B pixel provided with a B filter for transmitting blue-color light;

an S 1 pixel which is provided with an S 1 filter with a visible light transmittance independent of wavelengths in a visible light region across red, green and blue wavelengths and has a sensitivity higher than that of said R pixel; and

an S 2 pixel which is provided with an S 2 filter with a visible light transmittance independent of wavelengths in said visible light region across red, green and blue wavelengths and a transmittance that is lower than the visible light transmittance of said S 1 filter and has a sensitivity lower than the sensitivity of said S 1 pixel;

an optical system for guiding incident light to an imaging section of said solid-state imaging device; and

a signal processing circuit for processing a signal output by said solid-state imaging device, and further wherein filters for the S 1 and S 2 pixels alone determine a relative sensitivity for these pixels.

10. The electronic apparatus according to claim 7 , wherein a pixel signal saturation determination for the S 1 pixels determines which pixels are used for generating the image data.

11. The electronic apparatus according to claim 9 , wherein a green pixel signal is generated based on levels of a corresponding S 1 or S 2 pixel and R and B pixel data.