of Pilkington Bros. has been
identified as the inventor of the float glass process
even though it was first patented in 1848 by Henry
Bessemer, an English engineer. The float glass process
was also patented in the United States in 1902 by W. E.
Heal and again in 1925 by Hitchcock (a revised version of
Heal's patent). What Pilkington Bros. should be
recognized for is their success in commercializing the
float glass process, obtaining "Original License
Patents", restricting its use through licenses and
by defining it as "Confidential Information" in
their confidentiality agreements.
"Original Licensed Patents"
registered to Pilkington's in the U. S. relating to the
manufacturing of float glass have expired making the technology and
know-how contained within them public domain information. In
addition to the expiration of the "Original Licensed Patents", in
1986, a U. S. Federal Court published a slip decision at the request
of Pilkington in an attempt to win a law suit they had filed against
Guardian Industries. In the 1986 slip decision, the court declared
that Guardian breached Pilkington's "Original License Patents" and
"Confidential Information" by constructing their first float glass
plant in 1970. Guardian also breached Pilkington's "Confidential
Information" licensed to Ford Motor Company's glass division.
Because both Pilkington and Ford were aware of the breach and did
nothing about it, their rights expired in 1974 to the float glass
manufacturing technology and know-how. In summary, the court
declared that Pilkington's float glass manufacturing technology and
know-how was public domain information (see Note).
In addition to the
1986 U. S. Federal Court slip decision, in 1994 the U. S.
Justice Department obtained and published a consent
decree reached with Pilkington Bros. as the final
resolution to an anti trust law suit they filed against
them in Tucson, AZ. The consent decree (U. S.
Justice Department, case # CIV94-345TUCWDB Final Judgment
dated May 24, 1995 allows AJZ to use the information
contained with the "Original Licensed Patent"
and "Confidential Information" without having
to obtain permission or license from Pilkington Bros. or
any other float glass manufacturer.
Note: Public domain is what becomes of the
data/information contained within patents that expire.
This means that all of the patents claims can be used by
anyone to design and build a float bath for a glass
manufacturing plant. It also applies to confidential and
proprietary relating to the design, construction and
operation of a float bath (tin bath/float furnace)
information that has been used without permission
(breached) and no legal action was taken before the
statue of limitations expired (the number of years after
a breech was identified and known to have occurred by the