CHAPTER 2
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COPYRIGHT 2003 CANON INC. CANOSCAN 9900F REV.0 FEB. 2003 PRINTED IN JAPAN (IMPRIME AU JAPON)
Figure 2-9-1
Figure 2-9-2
Figure 2-9-3
2. Operating FARE Function
Two light sources mounted in CanoScan 9900F have different frequencies ( the FAU lamp
(cold cathode fluorescent lamp): 380- 700nm, and IR LED : 880nm). If there light sources are
used under the same optical system, the image will be out of focus(Figure 2-9-2).
CanoScan 9900F is equipped with FARE unit. This unit is placed between the CCD and
lens and is consists of a refraction glass that changes the refractive index of light and
electromagnetic switch that change the position of the refraction glass.
First, scan a film with light of the FAU lamp transmitting the refraction glass. Secondl,
scan a film with the IRLED and turn on the electromagnetic switch to move the refraction
glass to the position where no IR LED light can transmit the glass (Figure 2-9-3).
Above functions make it possible to obtain the scanned image with the focus of light on the
film while using two light sources with different frequencies.
Light Source
Film
Lens
Refraction Glass
(FARE Unit)
CCD
FAU Lamp
IR LED
IR LED
