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2-2-2.
Replication
pit
c::::::::J
'(=
9
glass disc
Nickel plating,,-§
c::::::::J
c:::::J
1
mother
~
remover
Ni~kel p l a t i n g - - - ~
stamper
stamping
plastic mould
=
Aluminum r e f l e c t o r ~
e~aporation
~
===
protection coating --"
reading side
both sid,e disc
~
.
.
. .
. .
. .
.
.
.
.
. .
==
.
.
.
. .
.
. . .
.
...
.
\
\
ad
.
.d
pit
re
mg st e
Fig. 2-8. Replication
12
Conductivity is given to the photo-resist surface of the master
disc by evaporation or plating. The disc is covered by Nickel plating
so that a mother disc is obtained.
Remover is coated on the mother and then the mother is Nickel
plated again, so that the resultant is a stamper. Flatness of the
stamper must be as flat as possible for reducing a warp and a distor-
tion of a disc.
An injection molding, a compression molding, or 2P molding can
be employed as the disc molding methods. The compression mold-
ing is that vinyl chloride pplymer is placed on the stamper, heated,
pressed, and cooled for transcription of pits. The 2P molding is that
a plastic solvent which can be stiffened by ultraviolet rays is poured
onto an acrylic cast plate and stiffened by ultraviolet rays for
forming the pits.
AlumJnum reflective layer of about 400A is evaporated on the
face where the pits were transcribed. A plastic protective coating is
placed over on the aluminum layer.
Two discs are put together to form a both side disc with the
protective coating sides facing each other. This disc ha,s the pits on
its two sides.
2-2-3.
Disc Specifications
Diameter:
Spindle hole diameter:
Thickness:
Recording range:
Track pitch:
Playing time:
Rotation:
Laser:
Signal coding:
q,300 mm (12 inches)
q,35 mm (installation hole)
1.25 mm x 2.5
mm
(incl. adhesive & label)
q,110 min to q,295 mm
l.67µm
CAY 30 min. (one side) (5,400 frames)
CL V 60 min. ( one side) ( I 0,800 frames)
CAY 1800rpm
CLV I800rpm to 680rpm
(line velocity: about 11 m/sec.)
He-Ne laser (X=0.6328µm)
Direct NTSC
Video
Sound
Sync tip;
7 .6 MHz
White peak; 9 .3 MHz
2.3MHz± I00KHz (CH-1/L)
2.8 MHz
:t
100 KHz (CH-2/R)
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