Canon Canoscan CS8000F Service Manual download pdf (Page 26)

CHAPTER 2

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2002 CANON INC. CANOSCAN 8000F REV.0 OCT. 2002 PRINTED IN JAPAN (IMPRIME AU JAPON)

Figure 2-9-1 Figure 2-9-2 Figure 2-9-3

2. Operation of FARE Function

The frequency of the FAU lamp (cold cathode fluorescent lamp) is 380-700nm, while that of

the infrared LED is 880nm, therefore, their light refractive indexes differ resulting in out of

focus (Figure 2-9-2).

As a solution, CanoScan 8000F employs FARE unit between the CCD and lens, which

consists of a refraction glass for changing the light refractive index and of an electromagnetic

switch for changing the position of the refraction glass.

Firstly, the FAU lamp scans a film passing through the refraction glass. Secondly, the

infrared LED scans a film, at the same time, the electromagnetic switch is turned ON to move

the refraction glass to the position where the infrared LED light does not pass through (Figure

2-9-3).

Finally, the FAU lamp and infrared LED can scan a properly focused film.

Light Source

Film

Lens

Refraction Glass

(FARE Unit)

CCD

FAU Lamp

IR LED IR LED

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Canon Canoscan CS8000F Service Manual Page 26