2. Moving the Lens
a. Moving the Lens in Y (vertical) Direction
The machine’s lens is mounted on a lens stage, which is moved in Y (vertical
direction) when the lens Y motor (M5) is rotated.
b. Moving the Lens in the X (horizontal) Direction
The lens X motor (M4) mounted behind the lens stage is used to move the lens in X
(horizontal) direction.
3. Lens Motor Control Circuit
The lens X motor (M4) and the lens Y motor (M5) are 4-phase stepping motors. Both
motors are controlled in the same way, and the lens X motor is discussed here.
The motor is controlled by the four types of motor drive signals from the DC controller
PCB: M4A, M4A*, M4B, M4B*. The direction of the motor is changed by changing the
timing at which these motor drive signals are sent.
To keep the lens X motor stationary, the lens X motor hold signal (X-HOLD) is
generated, thereby applying brakes in the form of a voltage lower than when rotating the
motor.
Figure 3-203
DC controller PCB
Q156
Micro-
processor
24V
24V
Lens X
motor
drive
circuit
Lens Y
motor
drive
circuit
J110A
-3
-6
-1
-2
-4
-5
X-HOLD
M4A
M4A*
M4B
M4B*
J736
J736
J739
M4
M5
Lens (X) motor
Lens (Y) motor
J110A
-12
-15
-10
-11
-13
-14
Y-HOLD
M5A
M5A*
M5B
M5B*
COPYRIGHT © 1997 CANON INC. CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 3 EXPOSURE SYSTEM
3-3