12.8.3 Compensation for damage and prejudice caused by the owner of an invalid patent having acted in bad faith Article 104(1) of LP-2015 provides that “a declaration of invalidation shall imply that the patent has never been valid” and thus cannot produce the effects provided for in Title VI115 of the Law. Article 104(3) of LP-2015, to establish the limits of such retroactivity vis-à-vis res judicata decisions, begins with the phrase “without prejudice to compensation for damage and prejudice that may be due when the owner of the patent has acted in bad faith”. That implies that a party injured by an invalidated patent is entitled to compensation for the damage and prejudice caused when the patent owner acted in bad faith. Such bad faith implies that the owner was aware of the cause of their patent’s invalidity116 and has to be assessed based on when the damage was caused.117 This enables a person convicted for infringing a patent later ruled invalid to recover amounts paid as compensation for the supposed infringement, so long as the validity of the patent was not discussed in the initial litigation. Effects of the patent and of the patent application.Judgment of the Provincial Court of Barcelona 77/2018 of February 6, 2018, ECLI:ES:APB:2018:949 (SAPB 77/2018): “Our understanding in this context is that the owner's bad faith depends on their knowledge at the time of the patent's invalidity and of their noncompliance with the requirements for patentability.”SAPB 77/2018: “Bad faith must be assessed based not on when registration was applied for but on when the owner decided to bring and persist in the infringement action, despite knowing that they had not met the novelty requirement.”