The Patent Right – and the Parable of the Pencil
What Right Does a Patent Give You?
everyone on the same page, let’s talk about what a patent right is, and is not.
A patent is a grant of a right. That right is the right to exclude. This is
important to understand. A patent right does not grant you the right to produce
and sell your own invention. You may have that right, but you did not get it
from your patent. I have found in my practice that this is one of the principle
areas of confusion for someone approaching patents for the first time. This is
so important to understand that I would like to tell you the Parable of the
The Parable of the Pencil
Imagine a time before the pencil was invented. Writing is done by
quill pens dipped in ink. Writing can be messy. Spills of ink. Blobs of ink on
the page. Do-overs.
A bright inventor (George) looks at this problem and decides to
solve it. He retires to his workshop and develops the pencil – a wooden rod
with a hollow core filled with graphite. You can carry it in your pocket –
write with it without carrying ink around. It is revolutionary.
George submits a an application to the Patent Office. The application describes
the problem (messy ink), describes the solution, includes drawings of how a
pencil is constructed, and ends with a claim as follows:
The Pencil Claim
1. A writing instrument,
a cylindrical rod of wood having a first and second end, the rod
having a hollow core; and
a material for making a
permanent mark on paper filling said core in said rod at least at said first
The examiner carefully reads the application, scans the prior art,
and concludes that this is novel. She grants George a patent. George now has
the patent right to exclude anyone from making a pencil as he has claimed it.
George builds a pencil plant and starts making big money selling
Fred (another inventor) starts using pencils and sees a problem
with them. Sure, they can be carried in your pocket; they eliminate the mess of
ink. But they still leave a permanent mark and if you make a mistake it still
requires a do-over. Fred notices that this graphite stuff is not permanently
bound to the paper so he retires to his workshop and invents an eraser.
Fred files a application in the patent office. The same examiner gets
it. Fred describes the problem – the current pencil leaves permanent mistakes.
He describes his solution – an eraser attached to one end of the pencil. He
includes drawings of how to construct it and ends with a claim as follows:
The Pencil With Eraser Claim
1. A writing instrument,
a cylindrical rod of wood
having a first and second end, the rod having a hollow core;
a material for making a
permanent mark on paper filling the core in said rod at least at said first
an eraser mounted on said
second end of said rod.
And in the body of the patent Fred is careful to define and
describe what an eraser is. But you will notice that Fred’s claim is George’s
claim with one additional element – the eraser mounted on one end.
What does the examiner do – does she grant Fred a patent? The
answer is probably yes. Unless she finds written evidence that someone else has
developed an eraser for a pencil.
So Fred receives a patent. So what patent right does he have?
Remember – the patent right is only the right to exclude. Fred can exclude
anyone (including George) from making a pencil with an eraser. George can
exclude anyone from making a pencil. So Fred cannot make his own invention –
because to do so he would first have to make a pencil.
This little parable teaches several important things to understand
1. A patent does not
necessarily give you the right to manufacture or sell your invention.
2. It is possible, in fact
common, to get valid patents by adding just one element to a patent claim.
George’s patent is often called a parent patent – Fred’s is a child. A parent
patent can have many children. The parent tends to dominate.
3. If Fred tried to make his
invention he would infringe another patent. Why did the patent office not warn
him of this? Because a patent office is not concerned with infringement. A
patent office is only concerned with validity of a patent. Fred’s patent is
valid. Infringement is a concern of courts, when an infringement charge is
4. Was Fred foolish to patent?
Not at all. His patent right could be important. If his invention is valuable
he can do a number of things. For instance, Fred could meet with George, show
him his pencil with eraser and point out to him that he could sell 3 times more
pencils if they had erasers on them. So a negotiation could take place in which
Fred gives George an exclusive license for pencils with erasers in return for
getting 5 cents for each one sold. Then George would revamp his factory, make
really valuable pencils and expand his business greatly. Fred would then retire
to Hilton Head and play golf, free of any worries of capital expenditures,
inventories, and grouchy employees. So the patent right was very valuable to
There are of course other possibilities. There could be cross
licensing, in which both George and Fred could end up in the pencil business
competing with each other but with royalties being paid.
How Claims are Written
Another teaching of this parable is how claims are written. Note
the claims exhibited above. All claims have essentially the same structure as
A preamble: A writing instrument
A transition phrase: comprising
Followed by a number of elements:
a cylindrical rod of wood having a first and
second end, the rod having a hollow core;
a material for making a permanent mark on paper
filling the core in said rod at least at said first end; and
an eraser mounted on said second end of said
The transition phrase “comprising” has a very specific meaning in
patent law. It means “including at least”. So a patent claim such as George’s
with only two elements is a broad and strong claim. It claims a writing
instrument including at least only two elements. But it also covers all pencils
with more elements because it claims at least the first two elements. A later
pencil can have many other things added to it but it still falls under the
description of George’s claim. That is why it captured Fred’s pencil with an
simplistic way of viewing claims is that claims with few elements are strong
with respect to catching potential infringers. As more elements are added the
claim is weakened. But as more elements are added the claim is more likely to
be valid – because it gets around more prior art. Fred’s claim is valid because
it got around George’s patent by adding an element. In a well-developed field
you will see claims with many elements – even as many as 6, 8. or 12. The next
time you pick up a patent see if you can identify the preamble, the transition
phrase, and the elements.
A disclaimer on the parable of the pencil. While I like the
parable of the pencil because it is a nice and simple illustration of many aspects of
patents, including the patent right – the pencil actually preceded the U.S.
Patent Office. Pencil like devices using lead were known in ancient Rome.
Graphite for marking came into use in the late 1500’s and mass produced pencils
were made in Germany in the 1600’s.