If it looks like a duck, swims like a duck, and quacks like a duck, then it is probably a duck, or so goes the old adage.
“A quackers idea for a patent”
Let’s assume, for a moment, that I have invented a robotic duck to keep me company, and have applied for a patent to protect him. I might consider a main claim as follows:
A robotic duck comprising a duck-shaped chassis, a swim thruster attached to the chassis, and a quack circuit.
Now, I’m a crafty patent attorney, and I have read section 125(1) of the UK Patents Act, which states:
[..] an invention […] shall, unless the context otherwise requires, be taken to be that specified in a claim of the specification of the application or patent, as the case may be, as interpreted by the description and any drawings contained in that specification […].
Similarly, Article 69(1) EPC states:
The extent of the protection conferred by a European patent or a European patent application shall be determined by the claims. Nevertheless, the description and drawings shall be used to interpret the claims.
My claim is therefore interpreted in view of the description and drawings, so I put a caveat into my description along the lines of:
For the purposes of the present invention, a duck is interpreted to be any animal in the Class Aves, a swim thruster is defined as any apparatus adapted to produce a movement appropriate for the specific animal in the Class Aves, and a quack circuit is defined as any circuit which produces an audible output corresponding with the specific animal in the Class Aves.
I have heard on the grapevine that a Silicon Valley billionaire is producing some sort of turkey. With my neat workaround in the description, surely I will catch all and sundry robotic poultry infringers? My description clearly states how the claims should be interpreted.
“Falling fowl of the previous judgments”
The summary provided in Virgin Atlantic Airways Ltd v Delta Airways Inc  gives a reasonable insight into the likely thought process of a judge in construing the claim above:
This [claim] is to be construed on familiar Kirin-Amgen principles: what would the person skilled in the art have understood the patentee to be using the language of the claim to mean?
It is the interpretation of the person skilled in the art which matters, and they are assumed to have read and understood the scope of the description and drawings, and infer therefrom the scope of the claims.
I have, however, clearly attempted to obscure the scope of the claims by using a word which has a specific meaning (duck), and, using the lexicon that is the description, attempted to broaden the scope of this term to achieve a more wide-ranging patent.
The Protocol on Article 69 – Interpretation of Article 69 provides an insight into the European position.
Article 69 […] is to be interpreted as defining a position between these extremes which combines a fair protection for the patent proprietor with a reasonable degree of legal certainty for third parties.
There is a critical overriding objective that the scope of the claims must be fair to both the patentee and third parties. The attempt to reclassify the term duck as meaning bird loosens the legal certainty for third parties, since a literal reading of the claims produces a wildly different outcome to the reading of the claims in view of the description.
“The technical bird of appeal’s view”
The judgment in T1175/04 gives a little context as to how my claim might be interpreted.
The expression “integrally formed” has a clear technical meaning [… of] made of a single piece or formed into a single piece. The use of the expression “formed integrally” in document D2 in respect of Figure 1 thereof (cf. column 3, lines 47 to 51) is not in conformity with the normal use of this expression in the English language and thus cannot give rise to an ambiguity of this expression. […].
Effectively, the technical board of appeal was asked what would be meant by the term integrally formed, in the context of an inventive step discussion. It was deemed that integrally formed can mean something which is made of a single piece or formed into a single piece. There is an ambiguity in the normal use of the expression in the English language. On the other hand, the use of the less common formed integrally was deemed to have a less ambiguous meaning, and therefore could only be interpreted in line with its use in the prior art citation reviewed.
This would seem to imply that the term duck would be interpreted narrowly, despite my attempts to alter the scope of the claim using the description. Duck has a common meaning in the English language; had I wished to claim broader protection, I should have used a broader term in my claim.
So perhaps the thing that looks like a duck, swims like a duck, and quacks like a duck is indeed a duck, even in the context of a patent application. It almost certainly won’t turn into a swan during infringement proceedings.
What can we therefore apply as “take-home messages”?
- Use plain and clear English in your claims to avoid misinterpretation; and
- Use claim terminology which is commensurate with the scope of protection for which you are seeking.