Carbon coatings in replicated optics art

DETAILED DESCRIPTION A principal object of the invention is to provide masters and replicated optical products having superior wear surfaces and wear surfaces which improve release characteristics during replication processes.
Another object of the invention is to provide amorphous carbon wear surfaces having the aforesaid improved wear and release characteristics.
A further object of the invention is to provide a process whereby compressive stresses of a amorphous carbon surface are carefully controlled to preserve, and even enhance, the optical properties of optical masters and the replicated optical products.
Other objects will be obvious to those skilled in the art on their reading of this disclosure.
The above objects have been substantially achieved by the provision of an improved surface for use with replicated optics, one formed of amorphous carbon and which also serves as an excellent wear surface for protecting the various critical surfaces used in the replicated optics art.
In one aspect of the invention, the discovery of the beneficial release properties of the i-carbon coating allows an easier, more dependable release of a replicated optical article from, say, a master.
Amorphous carbon coatings have been known for their wear-resistant properties.
However, they are even more notorious for the extraordinary compressive-forces which they generate--often a magnitude or more greater than commonly-coated inorganic material.
Thus, no matter how beneficial the other properties of a carbon coating may be, they are of little consequence unless the extraordinary compressive stresses of amorphous carbon can be controlled to avoid its tendency to pull away from the underlying surface and also to avoid the mechanical distortion of the optical surface, to which the carbon coating is well adhered.
The Inventor has addressed this problem and found that by careful control of both carbon-deposition kinetics and the thickness of the carbon layer, the compressive stress of the carbon coating can be reduced to a tolerable level, i