BenQ 2720S, Service Manual

Page: 24 / 67

The main module is composed of the main board. This module is located
at the bottom of the 2740S scanner. The I/O module is the SCSI output
port, and the line motor..
Scan Module
CCD/Sensor
Board
SCSI Output port
Main Board
Line Motor
Main Module I/O Module
Inverter
&
Lamp
ICE Function
Figure 5-2 Film Scanner System Block Diagram
When running in normal mode ,the light source(white light) comes
from a Lamp at CCD module, which is controlled by the Main Board, and
the light power comes from the Inverter Board on the scan module. The
image is passed through lens and into the CCD. The image are captured
from CCD (Charge Coupled Device). The CCD transfers light intensity to
electrical charges via photo-diodes, then these charges are sampled and
shifted serially with “analog charge coupled devices,” and converted, then,
into sampled voltage. The sampled voltage is transmitted to Main Board
and amplified by the differential operational amplifier. The image signals
are compensated with some digital/analog circuits and converted via the
A/D converter to get the digitized data.
Running in ICE mode is almost the same as normal mode , except for
light source coming from both the ICE Function and Lamp.
These digitized pixels are stored into the memory, which is managed
5-2 API Confidential Electrical Systems
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