IMAGE SENSOR HAVING IMPROVED SPECTRAL CHARACTERISTICS
The present invention relates to an image sensor sensor having improved spectral characteristics, and improves a color characteristic and sensitivity of an image sensor by implementing an image sensor sensor using a stacked substrate structure having photodiodes formed on each of two substrates, and generating a color signal having improved spectral characteristics based on an electrical signal outputted from each of the photodiodes formed on two substrates.
1 . An image sensor having improved spectral characteristics, comprising:
a first substrate including
a micro-lens suitable for concentrating a light;
an optical filter suitable for passing a light of a specific frequency band; and
a first photodiode suitable for converting a light signal that passes through the optical filter into an electrical signal,
a second substrate including a second photodiode suitable for converting the light signal that passes through the optical filter of the first substrate into the electrical signal;
an output driving circuit, which is formed on at least one of the first substrate and the second substrate, suitable for selectively outputting the electrical signals converted by the first photodiode and the second photodiode; and
a control unit suitable for generating a color signal having improved spectral characteristics based on the electrical signals, which are converted by each of the first photodiode and the second photodiode and which are outputted from the output driving circuit.
2 . The image sensor having improved spectral characteristics of claim 1 , wherein the optical filter includes a black and white filter, or a red, green and blue (RGB) color filter.
3 . The image sensor having improved spectral characteristics of claim 2 , wherein the optical filter further includes an infrared (IR) filter.
4 . The image sensor having improved spectral characteristics of claim 2 , wherein in case that the optical filter is the RGB color filter, the control unit improves a cross-talk caused by an infrared ray and improves a color characteristic by offsetting an output signal element of the second photodiode from an output signal element of the first photodiode.
5 . The image sensor having improved spectral characteristics of claim 2 , wherein in case that the optical filter is the black and white filter, the control unit improves a black and white sensitivity characteristic by reinforcing an output signal element of the second photodiode to an output signal element of the first photodiode.
6 . The image sensor having improved spectral characteristics of claim 3 , wherein in case that the optical filter is the IR filter, the control unit improves a sensitivity characteristic of an infrared ray by reinforcing an output signal element of the second photodiode to an output signal element of the first photodiode.
7 . The image sensor having improved spectral characteristics of claim 1 , wherein a spectral characteristic is adjusted by adjusting a thickness of at least one of the first substrate and the second substrate.
8 . The image sensor having improved spectral characteristics of claim 1 , wherein a spectral characteristic is adjusted by adjusting a thickness of at least one of the first photodiode and the second photodiode.
9 . The image sensor having improved spectral characteristics of claim 1 , wherein the first photodiode and the second photodiode are arrayed in multi-to-multi structure.
10 . The image sensor having improved spectral characteristics of claim 1 , wherein the first photodiode and the second photodiode are arrayed in multi-to-one structure.