Sony Cyber-shot PRO DSC-D700, Service Manual

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4-1 DSC-D700 (UC,CE)
SECTION 4
CIRCUIT DESCRIPTION
4-1. OPERATION THEORY OF CCD
A CCD (Charge Coupled Device) image sensor consists of a regularly laid-out MOS
(Metal-Oxide-Semiconductor) capacitor.
The MOS capacitor has three basic functions below that treat a charge.
1. Photoelectric Conversion (Photosensor)
When incident light falls on the MOS capacitor, the charge is generated in
proportion to the illumination received.
2. Charge Storage
When a voltage is applied to the electrode of a MOS capacitor, a “potential well”
is generated in the silicon layer. The charge is stored in this well.
3. Charge Transfer
When a higher voltage is applied to the electrode, a deeper well is generated.
When a lower voltage is applied, a shallower well is generated.
The charge is transferred using this characteristic. When a higher voltage is
applied to the electrode, a deeper “potential well” is generated. The charges
accumulated in an adjacent well flows into the “potential well”.
When this operation is sequentially repeated in the regularly laid-out electrode,
the charge is transferred from one MOS capacitor to another MOS capacitor.
This is the theory of the CCD charge transfer.