written on April 07, 2009 by David Burge
Misunderstandings about patents are common. For example, patents are often said to give their inventors a "monopoly" -- but, a patent seldom covers an invention sufficiently basic that it precludes the viable existence of competitors in a particular field of practice.
In truth, unless the invention protected by a patent is extremely basic, the grant of the patent does not even give to its owner the right to make, use, import and sell products that embody the invention protected by the patent. This is because the right granted by a patent is a negative right -- a negative right granted to the patent owner to "exclude others" from making, using, importing and selling the invention, not a positive right granted to the patent owner to exclusively make, use, import and sell the invention.
As is explained in the "The Parable of the Chair"1 found in the book Patent & Trademark Tactics & Practice,2 if a first inventor working in a primitive land where only logs and boulders are available to sit on, should patent a plank with three depending legs that form a stool, this stool invention of the first inventor may be so basic that the patent owner's negative right not only excludes others from making stool type sitting appliances, but also sets up the patent owner as the only entity entitled to provide stool type seating appliances to those who want them.
Should a second inventor in the same primitive land later patent a plank with four depending legs and an upstanding backboard, his patent on a chair type seating appliance may entitle him to prevent others from making, using, importing and selling chairs -- but, if the chair inventor himself wants to make, use, import and sell chairs during whatever years may remain of the term of the stool patent granted to the first inventor, the second inventor will need a license from the first inventor. This is because a chair assembly that includes four legs, a plank and an upstanding backboard infringes the first inventor's stool patent that gave the first inventor the right to exclude others from supplying seating appliances that include three legs and plank. Three legs and a plank to sit on are found in a chair which has four legs and a plank as well as an upstanding backboard.
Likewise, if a third inventor patents a plank with four depending legs, an upstanding backboard, two arms and two rockers connecting pairs of the legs that are assembled to form a rocking chair, his patent may entitle him to prevent others from making, using, importing and selling rocking chairs -- but, if the rocking chair inventor wants to make, use, import and sell rocking chairs, he will need licenses from each of the first and second inventors because the assembly of four legs, a plank and a backboard infringes the first inventor's patent protecting the use of three legs and plank, and infringes the second inventor's patent protecting the use of four legs, a plank and a backboard.
The need the third inventor may face to secure licenses from the first and second inventors will terminate when the patents granted to the first and second inventors expire -- but, when the first and second patents expire, members of the public will then be free to make, use, import and sell both stools and chairs, hence the third inventor's rocking chair will need to provide a much-wanted improvement over stools and chairs if the third inventor is to survive in a marketplace where stools and chairs can be made and sold by an unlimited number of competitors.
What this simple example illustrates is that few inventors are entirely free to exploit their inventions without taking into account what has been patented by their predecessors. Moreover, few patents actually protect inventions so basic that their owners enjoy anything even resembling a monopoly.
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1Available in complete and unabridged form at www.newnexperts.com/documents/parable_of_the_chair.pdf where "The Parable Of The Chair" is reprinted with the permission of the publisher, John Wiley & Sons.
2Published by John Wiley & Sons, 3rd ed. Copyright 1999, All Rights Reserved. ISBN 0471-32932-0.