Fig. 4-18 Optical Assembly Main Components - Canon NP-70 Service Manual

4-14
NP•70
4.3-2
ASSEMBLY MAIN COMPONENTS
The optical system consists of a lens unit and a light chamber. The latter contains a mirror,
dustproofing glasses 1 & 2, a dustproofing cover and a hood as shown in Fig. 4-18.
Mirror
Exposure
Dustproofing
Mask
Glass 2
Dustproofing Glass 1
Hood
Dustproofing Cover
Light Chamber
Fig. 4-18 Optical Assembly Main Components
Lens
Ass'y
Unit
Pivot
1) DUSTROOFING GLASS PLATES 1 & 2
They protect the minor and the lens inside the chamber from dirt by sealing up the chamber.
As an image passes through these glass plates, they must be completely clear and flawless to
pass the image correctly.
2) IMAGE MIRROR
This minor must reflect the image accurately to the lens unit, thus the reflection angle and the
plane angle are very critical.
3) DUSTPROOFING COVER
The light chamber is covered by this dustproofing cover to prevent the mirror and lens of the
optical chamber from being contaminated. Additionally, extraneous light is prevented from
entering the chamber.
Second Printing,lune, 1974 © CANON INC.