Image Sensor Pixel Charge Removal for Dynamic Range

The patent applies the discarding and recovering principle by intentionally removing excess charges from the photodiode through the removal transistor when saturation is detected. Instead of expanding storage capacity (which would reduce fill factor), the system discards overflow charges and recovers the ability to handle high-intensity light by controlling the charge removal timing, thus maintaining both dynamic range and fill factor.

The patent applies universality by making the photodiode serve multiple functions: it acts as both the primary charge generation element and the storage element. By controlling the removal transistor, the same photodiode can operate in different modes (accumulation vs. controlled discharge) to achieve wide dynamic range without requiring separate storage structures that would reduce fill factor.

The patent applies dynamics by making the charge removal capability dynamic and adaptive. The removal transistor is controlled based on real-time detection of charge saturation levels, allowing the system to adapt its sensitivity to varying light intensities. This dynamic control enables the pixel to maintain optimal sensitivity across different illumination conditions while achieving wide dynamic range.