Solid-state imaging device and electronic equipment
View Patent ↗A solid-state imaging device includes: a semiconductor substrate having a light receiving surface sectioned for red, green, blue, and white pixels arranged in a matrix with photodiodes formed thereon; color filters formed on the semiconductor substrate in light incident paths to the photodiodes of the respective formation regions of the red, green, and blue pixels and respectively transmitting lights in red, green, and blue wavelength regions; and photochromic films formed on the semiconductor substrate in the light incident path to the photodiodes in the formation regions of at least some of the white pixels, and containing a photochromic material having light transmittance varying in response to incident light intensity in a predetermined wavelength region, wherein a half period of the light transmittance of the photochromic films is shorter than one frame as a period in which pixel signals obtained in the pixels are read out with respect to all pixels.
1. A solid-state imaging device comprising:
a semiconductor substrate having a light receiving surface sectioned for red pixels, green pixels, blue pixels, and white pixels arranged in a matrix with photodiodes formed thereon;
color filters formed on the semiconductor substrate in light incident paths to the photodiodes of respective formation regions of the red pixels, the green pixels, and the blue pixels and respectively transmitting light in red, green, and blue wavelength regions; and
photochromic films formed on the semiconductor substrate in light incident paths to the photodiodes in formation regions of at least some of the white pixels, and containing a photochromic material having light transmittance varying in response to incident light intensity in a predetermined wavelength region,
wherein a half period of the light transmittance of the photochromic films is shorter than one frame as a period in which pixel signals obtained in the pixels are read out with respect to all pixels, and wherein first sets of pixels containing white pixels on which the photochromic films are formed and second sets of pixels containing white pixels on which no photochromic films are formed are alternately arranged on the light receiving surface.
2. The solid-state imaging device according to claim 1 , wherein the photochromic films are also formed on the semiconductor substrate in the light incident paths to the photodiodes of the respective formation regions of at least some of the red pixels, the green pixels, and the blue pixels.
3. The solid-state imaging device according to claim 1 , wherein each of the first sets of pixels and the second sets of pixels includes one red pixel, one green pixel, one blue pixel, and one white pixel, and a common photochromic film is formed with respect to each of the first sets of pixels.
4. The solid-state imaging device according to claim 1 , wherein each of the first sets of pixels and the second sets of pixels includes pixels arranged in one column in juxtaposition, and a common photochromic film is formed with respect to each of the first sets of pixels.
5. The solid-state imaging device according to claim 1 , wherein each of the first sets of pixels and the second sets of pixels includes pixels arranged in plural columns in juxtaposition, and a common photochromic film is formed with respect to each of the first sets of pixels.
6. The solid-state imaging device according to claim 1 , wherein the photodiode in the white pixel with the photochromic film formed thereon has an output part that logarithmically converts and outputs a value of a light signal corresponding to light charge generated in the photodiode.
7. The solid-state imaging device according to claim 1 , further comprising a light amount measurement part that measures an amount of light absorbed by the photochromic film.
8. The solid-state imaging device according to claim 7 , further comprising a signal processing part that combines a light signal according to the amount of light measured in the light amount measurement part and the light signal obtained in the photodiode of each pixel.
9. The solid-state imaging device according to claim 7 , further comprising a reset part that resets a light signal generated when the photochromic film absorbs light.
10. The solid-state imaging device according to claim 2 , wherein the photochromic films are formed using different materials corresponding to wavelength regions transmitted through the color filters.
11. The solid-state imaging device according to claim 2 , wherein the photochromic films are formed using the same material independent of wavelength regions transmitted through the color filters.
12. The solid-state imaging device according to claim 2 , wherein the photochromic film and the color filter are formed as the same film.
13. The solid-state imaging device according to claim 8 , wherein gamma correction processing and auto gain control processing are performed as signal processing in the signal processing part.
14. The solid-state imaging device according to claim 1 , wherein the photochromic film has light transmittance that changes in response to incident light intensity in a visible light region.
15. The solid-state imaging device according to claim 1 , wherein the light transmittance of the photochromic film in a visible light region is higher when the amount of incident light is smaller than when the amount is larger.
16. The solid-state imaging device according to claim 1 , wherein the light transmittance of the photochromic film in a visible light region continuously changes in response to the amount of incident light.
17. The solid-state imaging device according to claim 1 , wherein the photochromic material is a hexaarylbisimidazole derivative.
18. Electronic equipment comprising:
a solid-state imaging device;
an optical system that guides incident light to an imaging unit of the solid-state imaging device; and
a signal processing circuit that processes an output signal of the solid-state imaging device,
the solid-state imaging device including a semiconductor substrate having a light receiving surface sectioned for red pixels, green pixels, blue pixels, and white pixels arranged in a matrix with photodiodes formed thereon, color filters formed on the semiconductor substrate in light incident paths to the photodiodes of respective formation regions of the red pixels, the green pixels, and the blue pixels and respectively transmitting lights in red, green, and blue wavelengths, and photochromic films formed on the semiconductor substrate in light incident paths to the photodiodes of formation regions of at least some of the white pixels, and containing a photochromic material having light transmittance varying in response to incident light intensity in a predetermined wavelength region, wherein a half period of the light transmittance of the photochromic films is shorter than one frame as a period in which pixel signals obtained in the pixels are read out with respect to all pixels, and wherein first sets of pixels containing white pixels on which the photochromic films are formed and second sets of pixels containing white pixels on which no photochromic films are formed are alternately arranged on the light receiving surface.
19. The electronic equipment of claim 18 , wherein the photochromic films are also formed on the semiconductor substrate in the light incident paths to the photodiodes of the respective formation regions of at least some of the red pixels, the green pixels, and the blue pixels.
20. The electronic equipment of claim 18 , wherein each of the first sets of pixels and the second sets of pixels includes one red pixel, one green pixel, one blue pixel, and one white pixel, and a common photochromic film is formed with respect to each of the first sets of pixels.