Patent ID: 7820467

Claim:
A method of operating a solid-state imaging device having an integrated array of a plurality of pixels, each pixel having a photodiode for receiving light and generating photoelectric charges, a transfer transistor for transferring the photoelectric charges, a storage transistor, a floating region coupled to the photodiode via the transfer transistor, and a storage capacitor element for accumulating photoelectric charges overflowing from the photodiode via the transfer transistor and the storage transistor during an accumulating operation, the storage transistor controllably coupling or splitting potentials of the storage capacitor element and the floating region, the operating method comprising the steps of: turning off the transfer transistor and turning on the storage transistor for discharging the photoelectric charges of the floating region and the storage capacitor element, prior to accumulating charges; reading out a voltage signal at a reset level of the floating region and the storage capacitor element; accumulating, in the photodiode, pre-saturated charges among the photoelectric charges generated in the photodiode and accumulating, in the floating region and the storage capacitor element, supersaturated charges overflowing from the photodiode; turning off the storage transistor to split potentials of the floating region and the storage capacitor element and discharging the photoelectric charges in the floating region; reading out a voltage signal at a reset level of the floating region; turning on the transfer transistor so as to transfer the pre-saturated charges to the floating region and reading out a voltage signal of the pre-saturated charges; turning on the storage transistor to couple the potentials of the floating region and the storage capacitor element for mixing the pre-saturated charges and the supersaturated charges and reading out a voltage signal of a sum of the pre-saturated charges and the supersaturated charges; canceling noise of a voltage signal of a sum of the pre-saturated charges and the supersaturated charges by taking a difference between the voltage signal of the sum of the pre-saturated charges and the supersaturated charges and a voltage signal at a reset level of the floating region and the storage capacitor element; adjusting a gain of the voltage signal of the sum of the pre-saturated charges and the supersaturated charges so as to make the gain substantially the same as a gain of the voltage signal of the pre-saturated charges; and selecting either one of the noise-cancelled voltage signal of the pre-saturated charges and the noise-cancelled voltage signal of the sum of the pre-saturated charges and the supersaturated charges by comparing with a reference voltage.