Dick Tracy played a role in patent history. Tracy's comic book
renderings of a futuristic means of communication using a wristwatch
radio were used as prior art to deny a patent application when an
inventor applied for a patent on the wristwatch radio he designed. The
burden of proving "novelty" falls upon the applicant, and the law allows
the Federal Courts to set aside a patent which is disclosed in prior
art, is obvious or defies physics.
The first test of the validity of a patent is prior art. According to a
Patent and Trademark Office (PTO) publication, an invention cannot be
patented if "(a) The invention was known or used by others in this
country, or patented or described in a printed publication…, before the
invention thereof by the applicant for patent, or (b) The invention was
… in public use or on sale in this country more than one year prior to
the application for patent in the United States…" Many times the courts
set aside granted patents because of prior art not revealed by the
The second test for a patent is whether or not the invention is obvious.
Even if the idea to be patented is not exactly shown in prior art, a
patent may still be refused if the differences are obvious. To be
patented, an idea must be different enough so that it is unobvious to a
person having ordinary skill in the area of technology related to the
The third test requires the invention to be possible. In other words,
the concepts and processes involved must be true and real, and the
invention, as described in the patent, must work.
AAROFLEX has researched and collected over 5000 pages of documents
pertaining to three-dimensional printing processes which demonstrate
prior art in the area of stereolithography. The use of light to create
three-dimensional objects was first introduced by Frenchmen E. Luzy and
C. Dupuis in 1912 with the French patent 461,600. The use of UV light to
harden a photopolymer was introduced into the public domain by Otto John
Muntz upon the expiration of his U.S. patent 2,775,758, referred to as
"photo-glyph recording", in 1973.
The concept of stacking two-dimensional cross-sections to form a
three-dimensional objects dates back to 1981, when Hideo Kodama, a
Japanese researcher, published an article concerning his research on the
concept of 3D printing in which he discussed fabricating solid models by
stacking cross-sectional layers of photo-hardening polymer. 1982, Allen
Herbert, of 3M company, published an article in which he discussed using
a laser beam to selectively solidify a photo-polymer to sketch and stack
cross-sectional layers to create a three-dimensional object.
Other components and mechanisms, such as perforated platforms are an
example of obvious use, as the concept has been in use throughout time
to separate solid objects from liquid objects in machinery such as
washers and dryers, and utensils as simple as a sieve. Any person
looking to separate solidified resin from liquid resin would have
devised a perforated platform.
Most stereolithography concepts and processes have been made available
in the public domain via expired patents, publications and technical
papers. The specific mechanisms of the stereolithography machines may be
patented if they are sufficiently novel and unobvious; however, AAROFLEX
conducted in depth research and obtained five patent opinions stating
that the AAROFLEX technology does not infringe upon the valid patents of
any competitor. Patent litigation in the area of stereolithography will,
most likely, only serve to invalidate currently held patents, and
further open the market to competition.
Albert C. Young, Jr., P.E.
8550 Lee Highway, Suite 525
Fairfax, VA 22031
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