– 4 –
Fig. 1-6. Horizontal Transfer of CCD Imager and Extraction of Signal Voltage
Fig. 1-7. Theory of Signal Extraction Operation
5. Transfer of Electric Charge by the Horizontal CCD
The transfer system for the horizontal CCD emplays a 4-phase drive method.
The electric charges sent to the final stage of the horizontal CCD are transferred to the floating diffusion (FD), as shown in Fig.
1-6. PR is turned on by the timing in (1), and the floating diffusion is charged to the potential of RD.
The PR is turned off by the timing in (2). In this condition, the floating diffusion is floated at high impedance.
The H2 potential becomes shallow by the timing in (3), and the electric charge now moves to the floating diffusion.
Here, the electric charges are converted into voltages at the rate of V = Q/C by the equivalent capacitance C of the floating
diffusion. PR is then turned on again by the timing in (1) when the H2 potential becomes deep.
Thus, the potential of the floating diffusion changes in proportion to the quantity of transferred electric charge, and becomes
CCD output after being received by the source follower. The equivalent circuit for the output circuit is shown in Fig. 1-7.
6. Lens drive block
6-1. Shutter drive
The regulator (IC952) drives by P ON signal which is output
from the power control IC (IC501) is drived, and then power is
supplied to iris shutter drive IC (IC951). The drive signal
(GPIO4, GPIO5, GPIO6, GPIO7) which is output from the
ASIC (IC102) is drived the iris shutter drive IC (IC951), and
the iris shutter spring is open and closed.
Reset gate pulse
20 V Pre-charge drain bias (PD)
Direction of transfer
Voltage output
Electric
charge
H Register
Floating diffusion gate is
floated at a high impedance.
C is charged
equivalently
H1 H4 H3 H2 H1 H4 H3
(1)
(2)
(3)
H3
H4
H1
CCD OUT
(1)(2) (3)
H2
OG
PR
FD
RD
H1 H4 H3 H2 H1 H4 H3
H2
OG
PR
FD
RD
H1 H4 H3 H2 H1 H4 H3
H2
OG
PR
FD
RD
H2
PR
