The 1969 idea was clocked charge storage
Boyle and Smith conceived the charge-coupled device in 1969, initially in a memory context. Voltages on neighboring gates reshape potential wells, moving stored charge without giving each pixel its own amplifier.
Its imaging use combined that transport mechanism with photoelectric charge generation. Later sensor development turned the idea into practical cameras; the Nobel award in 2009 recognizes the CCD invention.
Exposure and readout happen in different stages
During exposure, a pixel collects electrons from absorbed photons, together with dark charge. During readout, a sequence of clocks passes the packet through neighboring wells and a serial register to an amplifier. Pixel order is carried by that sequence.
Sources: [1]
Small transfer errors accumulate
Traps can delay electrons, leaving a trail behind a bright packet. Even excellent per-transfer efficiency compounds over many shifts. Read noise is added at the amplifier, so it is distinct from charge lost or deferred during transport.
Sources: [1]
The new Lab follows each packet to the amplifier
The CCD Lab displays phased gates and charge transport, then compares stored packets with read samples. Its synthetic transfer and noise controls isolate those stages. Lens focusing belongs to the existing camera-optics work and is not rebuilt here.