Solid-state imaging element, manufacturing method of the same, and electronic device
The present technology relates to a solid-state imaging element, a manufacturing method of the same, and an electronic device that achieve the extension of a dynamic range by making a difference in light-receiving sensitivity between low-sensitivity pixels and high-sensitivity pixels without changing spectral characteristics. The solid-state imaging element includes a pixel array portion in which two kinds of pixels different in light-receiving sensitivity, high-sensitivity pixels and low-sensitivity pixels are arrayed. The low-sensitivity pixels have a gray filter on or under a color filter to decrease light transmission factor in a visible-light region by a predetermined ratio. The present technology is applicable to solid-state imaging elements and the like, for example.
1. A solid-state imaging element, comprising:
a pixel array portion that comprises a plurality of low-sensitivity pixels and a plurality of high-sensitivity pixels, wherein
each low-sensitivity pixel of the plurality of low-sensitivity pixels comprises:
a gray filter;
a flattened film; and
a color filter;
the color filter is between the gray filter and the flattened film, and
the gray filter is configured to decrease a light transmission factor in a visible-light region by a ratio.
2. The solid-state imaging element according to claim 1 , wherein the color filter is at least one of a Red (R) color filter, a Green (G) color filter, a Blue (B) color filter, and a Clear (C) color filter.
3. The solid-state imaging element according to claim 2 , wherein an average transmission factor of the C color filter in wavelengths of 400 nm to 700 nm is one of 90% or more.
4. The solid-state imaging element according to claim 2 , further comprising an on-chip lens, wherein the C color filter includes a material same as that for the on-chip lens.
5. The solid-state imaging element according to claim 1 , wherein
an array of color filters in the plurality of low-sensitivity pixels is same as an array of color filters in the plurality of high-sensitivity pixels,
the plurality of low-sensitivity pixels is in a two-dimensional arrangement, and
the plurality of high-sensitivity pixels is in a two-dimensional arrangement.
6. The solid-state imaging element according to claim 1 , wherein the plurality of high-sensitivity pixels and the plurality of low-sensitivity pixels have different pixel sizes.
7. The solid-state imaging element according to claim 1 , wherein
each pixel, of the plurality of low-sensitivity pixels and the plurality of high-sensitivity pixels, comprises an inter-pixel light-shielding film,
the inter-pixel light-shielding film comprises an opening region for each pixel of the plurality of low-sensitivity pixels and the plurality of high-sensitivity pixels, and
the plurality of high-sensitivity pixels and the plurality of low-sensitivity pixels correspond to different opening region sizes.
8. The solid-state imaging element according to claim 1 , wherein a first depth-wise position, at which a photo diode is present in a pixel of the plurality of low-sensitivity pixels, is different from a second depth-wise position at which a photo diode is present in a pixel of the plurality of high-sensitivity pixels.
9. The solid-state imaging element according to claim 1 , wherein a light-receiving sensitivity of each pixel of the plurality of low-sensitivity pixels is one of 50% or less of a light-receiving sensitivity of each pixel of the plurality of high-sensitivity pixels.
10. The solid-state imaging element according to claim 1 , wherein the gray filter includes a material in which a light-shielding material is dispersed in an organic resin.
11. The solid-state imaging element according to claim 10 , wherein the light-shielding material is one of an organic pigment, an inorganic pigment, or carbon black.
12. The solid-state imaging element according to claim 1 , wherein
the gray filter has an average transmission factor of 10% to 90% in wavelengths of 400 nm to 700 nm,
the light transmission factor, of a plurality of light transmission factors of the gray filter, correspond to a wavelength in the wavelengths of 400 nm to 700 nm, and
the plurality of transmission factors is within a range of −15% to +15% of the transmission factor in a wavelength of 550 nm.
13. The solid-state imaging element according to claim 1 , wherein a film thickness of the gray filter is within a range of 100 nm to 1000 nm.
14. The solid-state imaging element according to claim 1 , wherein the gray filter comprises layers of a plurality of kinds of films.
15. The solid-state imaging element according to claim 14 , wherein one of the plurality of kinds of films is a film including a material in which a light-shielding material is dispersed in an organic resin.
16. A manufacturing method of a solid-state imaging element, the method comprising:
forming a gray filter on a color filter to decrease a light transmission factor in a visible-light region by a ratio for a plurality of low-sensitivity pixels of the solid-state imaging element, wherein
the solid-state imaging element comprises a pixel array portion,
the pixel array portion comprises the plurality of low-sensitivity pixels and a plurality of high-sensitivity pixels,
each low-sensitivity pixel of the plurality of low-sensitivity pixels comprises:
the gray filter;
a flattened film; and
the color filter, and
the color filter is between the gray filter and the flattened film.
17. An electronic device, comprising:
a solid-state imaging element including:
a pixel array portion that comprises a plurality of low-sensitivity pixels and
a plurality of high-sensitivity pixels, wherein
each low-sensitivity pixel of the plurality of low-sensitivity pixels comprises:
a gray filter;
a flattened film; and
a color filter,
the color filter is between the gray filter and the flattened film, and
the gray filter is configured to decrease a light transmission factor in a visible-light region by a ratio.