BenQ 2720S, Service Manual

Page: 31 / 67

The image are captured from color CCD (Charge Coupled Device). The
CCD transfers the light intensity to electrical charges via photo-diodes,
then these charges are sampled and shifted serially with analog charge
coupled devices and, then, converted into sampled voltage. The sampled
voltage is amplified and transmitted into MainBoard. The block diagrams
of ASP are described in figure 5-7.
5.5 CCD Head/Elements
This section describes the CCD head module, and other elements
( includes: line motor, home sensor, and panel ).
The CCD Board contains the CCD, CCD signal amplifier, which is mounted
on this board. As illustrated in figure 5-8
A m p lif ie r
C o lo r C C D
+ 1 2 V R e g u la to r
M a in
B o a r d
Figure 5-8 Film Scanner CCD Board
5.5.1 Line Motor Driver
The Line Motor is driven by the L6219. It is a bipolar motor driver. Given
the clock pulses and the necessary power, it is very easy to interface with
the bipolar stepping motor.
5.5.2 Sensor Elements
The home sensor: a photo-coupler is mounted on the panel sensor board
to do the home positioning job, when the 2740S scanner is calibrating or
returning after finishing a scan.
Electrical Systems API Confidential 5-9
No Copy/Reproduction allowed