A 1/2.5-inch 8Mpixel CMOS image sensor with a staggered shared-pixel architecture and an FD-boost operation

In order to shrink pixel sizes for mobile phone cameras, several shared-pixel architectures have previously been proposed [1–3]. However, the use of conventional shared-pixel architectures leads to a Gr/Gb sensitivity imbalance because the Gr pixel and the Gb pixel have a different layout structure when using a Bayer Color Filter Array (CFA) [3,4]. The Gr/Gb sensitivity imbalance causes conspicuous fixed-pattern noise in reproduced images [4]. In many cases, the noise level has a scene-color temperature dependence, due to the sensitivity imbalance caused by the attenuation of the incident light by the electromagnetic effect. Therefore, conventional shared-pixel architectures need complicated digital signal processing to properly correct for this Gr/Gb sensitivity imbalance.