Infringement, Validity Challenges, Remedies and Enforcement
Infringement
Infringement is assessed by comparing the construed claim with the alleged infringing product or process. Direct infringement requires all essential integers to be present; absence of one integer means no infringement. Candidates must also know the contributory and authorisation provisions: supplying a product for use in a patented process, and authorising another to exploit the invention.
Exemptions and defences
Statutory exemptions include private use, experimental use, and use for obtaining regulatory approval. Traps: treating experimental use as covering commercial trials; overlooking the regulatory-approval exemption; and forgetting that a defendant may counterclaim for revocation, putting validity in issue.
Validity challenges
Revocation can be sought on the s 18 grounds, plus grounds such as fraud, false suggestion, and failure to disclose. The standard of proof is the balance of probabilities. Candidates should know that a successful validity challenge defeats the infringement claim entirely.
Remedies
Available remedies include an injunction, damages or an account of profits (not both), and delivery up. Additional damages may be available for flagrant infringement. Innocent infringement may reduce damages.
Worked example
A patent claims a three-component device. The defendant's product omits one component and achieves the same result another way. If the omitted integer was essential, there is no infringement; if it was non-essential, infringement may lie. Rule of thumb: always construe the claim first, then compare integer by integer, and only then consider defences.