Back to results
US 4,564,932 AGranted
Method of fabrication of a protected optical disk and a disk obtained by said method
AssigneeThomson-CSF
InventorFrancois Lange
Life of this patent
Estimating the term…
Abstract
A protected optical disk for recording information is fabricated by a method whereby at least one cover is rigidly fixed by a welding to an optical disk having at least one layer of recording material which can be both written and read optically. At least two joints are thus formed by welding, each joint being constituted by at least two weld zones each located respectively within a concentric ring.
Claims8
A protected optical disk comprising a protective casing of thermoplastic material, annular optically recordable structure enclosed in said casing;
- said casing being made of at least first and a second disk shaped member delimiting an annular chamber and assembled to each other with welded circular joints;
- said first disk shaped member having an annular recess in confronting relationship with said recordable structure and two ring shaped raised portions respectively inwardly and outwardly bounding said annular recess;
- said second disk shaped member mating said raised portions;
- said welded circular joints extending between said second disk shaped member and said ring shaped raised portions for sealing said casing;
- at least first and second of said welded circular joints being spaced and concentrically arranged on one side of the inner and outer sides of said annular recess;
- one of said disk shaped members having an inner flat face supporting said recordable structure;
- the radial spacing of said first and second welded circular joints lying in a range from 0.4 to 6 millimeters.
4 more elements
Dependencies are inferred from the claim text.