Kodak DirectView CR 825 Theory Manual page 58

THEORY GUIDE
10DEC05
GALVO
TG4825-1
Page
58 of 120
A3
DIGITIZER
BOARD
The GALVO moves the laser beam to scan the SCREEN:
• rotates the GALVO MIRROR to cause the laser beam to scan across the SCREEN - fast
scan
• moves to the beginning of the next line on the SCREEN
• scans the next line until the SCREEN is fully scanned
The GALVO uses a feedback system in which the desired position of the GALVO MIRROR is
compared to the actual position in the rotation, and corrections are made to keep the GALVO
in the correct position on the SCREEN at the correct time. When the GALVO is in the correct
position, the laser beam is also in the correct position.
A4
GALVO BOARD
Clock Signal
Desired Position
Plate Size
Offset and Amplitude
Line Start Signal
Desired Position Signal
Closed Loop
Servo Circuit
Drive Signal
Actual
Position
Signal
PRE-REGULATOR
GALVO
MIRROR
GALVO
A18 A17
LASER DRIVER LASER DRIVER
DIODE BOARD
BOARD
Optical
H194_5041HC