Sony Proposes BCMD with Reduced Dark Current

Sony patent application US20170229493 "Pixel circuit and imaging apparatus" by Kouichi Harada and Toshiyuki Nishihara proposes dark current reduction in bulk charge modulated device (BCMD).

"...the above image sensor needs to read 1000 times in one frame for example, and has problems of increase in read voltage and increase in read time. Also, as the number of reads per frame increases, dark current of the FD increases proportionally. As a result, the dark current of the FD becomes the main component of the dark current of the pixel. The dark current of the FD is unable to be reduced easily, and thus even if the conversion efficiency can be set to 600 μV/e−, the accuracy of detecting one photon is reduced. If there is no FD, the accuracy of detecting one photon is improved.

...According to the present technology, it is possible to obtain an excellent effect that the dark current of the FD in the image sensor is eliminated, and that the conversion efficiency of converting the electric charge to a voltage can be improved."