Facing a patent infringement lawsuit threatens your products, business operations, and finances. Accused infringers must develop defense strategies that can defeat infringement claims, invalidate asserted patents, or minimize potential damages. Understanding available defenses and strategic options helps defendants respond effectively to patent assertions.
Non-Infringement Defenses
The most straightforward defense argues that accused products don't actually infringe the asserted claims. Non-infringement analysis focuses on claim construction, seeking interpretations that exclude accused technology. If claims are construed to require elements missing from your products, infringement fails regardless of how similar your technology appears to the patented invention.
Detailed technical comparison between claim elements and accused products forms the foundation of non-infringement defenses. Expert witnesses explain technical differences and why accused products don't practice claimed limitations. Even minor differences can establish non-infringement if claims require specific features your products lack.
Invalidity Challenges
Invalid patents cannot be infringed, making invalidity a complete defense. Prior art showing the claimed invention was known or obvious before the filing date can invalidate patents. Inadequate patent disclosure, improper claiming of inventions, and other defects in the patent application process may also establish invalidity.
Prior art searches for references predating the patent can reveal anticipatory art showing the exact invention or combinations making the invention obvious. Patent owners cannot claim inventions the public already possessed. Inter partes review proceedings at the Patent Office provide alternative venues for challenging validity with lower burdens of proof than litigation.
Inequitable Conduct
Patents obtained through misconduct during prosecution may be unenforceable due to inequitable conduct. When patent applicants deceive the Patent Office by withholding material prior art or making false statements, the resulting patents may be unenforceable regardless of validity. This defense requires showing both materiality and intent to deceive.
Prosecution history review may reveal undisclosed prior art the applicant knew about, mischaracterizations of reference teachings, or other conduct suggesting deception. While inequitable conduct defenses are difficult to prove, they can render entire patents unenforceable when established.
License and Exhaustion Defenses
Defendants may have express or implied licenses to practice claimed inventions, negating infringement. Licenses arise from contracts, patent holders' conduct, or legal doctrines like implied license from authorized sales. Patent exhaustion prevents patent holders from controlling products after authorized sales, limiting their ability to pursue downstream purchasers or users.
First sale doctrine exhausts patent rights in specific items after authorized sales. Purchasers of patented products can use and resell them without infringement. Exhaustion limits patent holder control over distribution chains and secondary markets.
Strategic Considerations
Defense strategy balances litigation costs, business impacts, and settlement possibilities. Aggressive defenses may defeat weak claims but cost substantial legal fees. Settlement through licensing may preserve business relationships while avoiding litigation risk. Design-arounds modifying products to avoid infringement offer alternatives to litigation.
Evaluate assertion economics including plaintiff motivation, settlement demands, and litigation costs. Patent trolls seeking quick settlements face different calculus than competitors seeking market exclusion. Understanding plaintiff goals helps formulate appropriate defense and settlement strategies.