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One more foveon like Sony patent!


The three layer design from Sony

And here it is the next back-illuminated and three color layer Sony sensor patent! You can read the full (and very technical) description at freepatentsonline (Click here). It is not the first time we see such a “foveon like” patent. Sigma is currently the only manufactures that produces cameras based on that concept Like the new Sigma DP2s and SD15.

Here is the original patent description:
In recent years, in the CCD image sensor or the CMOS image sensor, since the size of a pixel decreases and the number of photons incident on a unit pixel decreases, sensitivity deteriorates and thus a decrease in S/N occurs. In widely used pixel arrangement where red, green, and blue pixels are arranged on a planar surface, for example, the Bayer arrangement using the primary color filters, green and blue light does not penetrate a color filter in red pixels and is not used in photoelectric conversion. Therefore, sensitivity may decrease. Moreover, when a color signal is formed by executing an interpolation process between pixels, a problem of a false color may arise.
In order to solve these problems, Japanese Unexamined Patent Application Publication No. 2007-12796 discloses a solid-state imaging device in which green, blue, and red photoelectric conversion units are laminated in a depth direction of the same pixel. In the solid-state imaging device, a blue photodiode (photoelectric conversion unit) and a red photodiode (photoelectric conversion unit) are formed in the depth direction in a silicon substrate. In addition, the solid-state imaging device includes an organic photoelectric conversion unit in which a green organic photoelectric conversion layer interposed between electrodes is formed on the upper layer of the front surface of the silicon substrate on the side of a light incident side with a wiring layer interposed therebetween. According to the configuration disclosed in Japanese Unexamined Patent Application Publication No. 2007-12796, since a light loss does not occur in the above-mentioned color filter, the sensitivity is improved. Moreover, since the interpolation process is not performed between pixels, a false color does not occur.

The patent description is very long and complicated and I would appreciate if you could help me to find some interesting details. Thanks!

P.S.: I don’t expect the A77 or NEX-7 cameras to feature such a sensor. But in my opinion “Foveon-like” sensors are the future!

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