HomeOpinionIntellectual Property Perspectives: Infringement of patent rights

Intellectual Property Perspectives: Infringement of patent rights

Richard Pasipanodya

IN this 42nd instalment, we canvass acts of infringement of patent rights and their establishment.


                 Putting into perspective
“The ultimate accolade for a patentee is to prosecute successfully an action for infringement against a competitor who has copied his invention, in face of a counterclaim for revocation on the basis that the patent is invalid,” states author Brian C. Reid.
From this statement, it follows therefore that patent infringement is essentially a statutory tort founded on two fundamental premises, namely; whether the act complained of is one that inherently constitutes infringement, and if so, whether the patent, as claimed, covers the alleged infringement act. In this enquiry, the onus rests upon the patentee to, on a balance of probabilities, prove the infringing act.
  Acts of infringement
Acts of infringement are premised on standard commercial practices by which the infringer may make inroads into the patentee’s monopolistic rights. Among these are making, using, exercising, disposing of or offering to dispose of, or importing the patented product or process.
    Establishment of infringement
The determination of the scope of protection or ambit of the monopoly afforded by a patent is one of the most difficult and yet important tasks in patent law. This is because there are very few cases where this scope is crystal-clear merely by construing the patent document. Also, it is equally rare for the alleged infringement to be a carbon-copy of that which is described or illustrated in the patent specification. The courts will only arrive at this determination after hearing the parties’ contentions as to the preferred construction of the patent document.
In this pursuit it is incumbent on the courts to give the patent claims the same construction for infringement as that applied to validity of patents. In which regard where the patentee urges for a wider construction of the patent claims, they may be surprised to find out later that they have in fact simultaneously opened the door to a wider attack on the validity of their patented inventions on grounds of either novelty or obviousness. Conversely, where a defendant urges for a narrower construction of the patent claims, they may receive shock waves to find their claim for invalidity eroded, hence failing. This is termed “squeeze” in patent infringement or validity enquiries.
In the aftermath distilled from the courts’ jurisprudence over the years are the following succinctly stated guidelines:
      Guideline 1
The apparent boundary or ambit of patent monopoly is delimited by the ordinary, literal or primary meaning of the words as couched in the claims. Accordingly, the function of patent claims is to clearly and precisely define, without any possibility of doubt or confusion, the extent of the claimed monopoly in such a manner that third parties will be able to know the exact boundaries of the area within which they will be trespassers. The primary objective is to limit and not to unduly extend the scope of the monopoly claimed.
In this pursuit, therefore, when construing or interpreting patent claims, it is not permissible for the court to limit or extend the patent monopoly by importing non-existent wording or stray phrases into the claims or specification, but to construe the claims against the background of the complete specification as a whole. In consequence whereof what is not claimed is disclaimed.
Guideline 2
The boundary or scope of the patent monopoly must be determined or ascertained from the patent alone without an eye or mischief to accommodate the alleged infringing act’s anticipation of the patented invention. That is to say, courts must by all ethics adopt an objective approach in construing the patent and not twist the ordinary meaning of the claim and specification so as to catch an infringer whose actions are perceived as morally reprehensible or unacceptable to trade practices.
          Guideline 3
While the court may receive expert evidence as to the meaning of the technical terms in the claims, it must not thereby surrender its function and task of ultimately ascertaining the boundary of the claims to the witnesses. In this regard expert witnesses are precluded from stating what the specification means except to present evidence as to:


  • the state of the art as at any given time under review;
  • explaining the meaning of the technical terms used in the state of the art;
  • stating their opinion as whether what is described or illustrated in the specification is capable of industrial application by a skilled person, and
  • whether the described method of working the invention could be carried out by the skilled worker to give the desired technical result.

Guideline 4
Beyond its ordinary literal meaning, a claim must additionally be given a “purposive meaning.” This guideline, popularly termed the “doctrine of purposive meaning” postulates that the construction of claims should go beyond their ordinary literal meaning to embrace the purpose and function of each essential features or integers of the invention. In which pursuit the question would be whether the patentee intended that strict compliance with the ordinary meaning of the wording of the claims was an essential requirement on how the invention works.
Guideline 5
The court must distinguish between the essential and non-essential features of the claimed invention so as to establish the scope of patent monopoly based on the essential features alone. Having ascertained the essential features of the claimed invention, the court then compares these claimed features to those corresponding features of the alleged infringing articles.  In this regard, the alleged infringing article must have incorporated all the essential features of the claimed invention disregarding, of course, non-essential features.
  Guideline 6
It is neither justifiable nor permissible for a court to artificially strain the construction of the claim so as to include in the scope of the patent monopoly some material variant to the essential features of the invention which has a material effect on the working of the claimed invention. This would be tantamount to unethically extending the boundaries of the patent monopoly beyond what is originally claimed by the patentee.
     Guideline 7
That the alleged infringing article represents an improvement of the patented invention does not in itself necessarily exclude it from infringement. Though separately eligible for patent protection, what matters in this case is whether or not it falls within the claims of the patented invention as properly construed. For, such inventions may be the product of “…superadding of ingenuity to a robbery” of a validly patented invention without the permission of the proprietors thereof.
Guideline 8
Though it is perfectly permissible to include a variant of some given essential features of an invention, this may only be validly done where it obviously is of equivalent function to the claimed feature, provided this is done as at the time of publication of the patent and not thereafter.
Guideline 9
The courts will not extend the scope of patent protection by including variant features to the claimed invention where the patentee will have committed themselves to the exclusion of variants. The rationale being that by such committal, the patentee will have intended to confine themselves to the ordinary meaning of the wording of their claims, and are thus accordingly debarred from unfairly having a second bite of the cherry.


  • Pasipanodya is an IP consultant who writes in his own capacity. Feedback on: mobile +263 775053007, or e-mail:henripasi@gmail.com.

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