An International Guide to
Patent Case Management for Judges

12.4.2 The effects of invalidity

12.4.2.1 Partial invalidity of a patent

A claim is either invalid or valid in its entirety. If the invalidity affects only part of a claim, the claim can be limited in accordance with Article 102(2) of LP-2015, but only the owner can propose such limitation (Article 103(4) of LP-2015). The court cannot limit a claim through partial invalidation. It can only invalidate the claim in its entirety. In referring to total or partial invalidity of a patent, Article 104(5) of LP-2015 speaks of invalidating all or some of its claims, but not of partially invalidating a single claim. This was better explained in Article 112(2) of LP-1986:

Where the causes of invalidation only affect part of the patent, partial invalidation shall be declared through annulment of the claim or claims affected by those causes. Partial invalidation of a claim may not be declared.

Now, while the earlier explicit provision has been rescinded, the rule preventing partial invalidation of a claim still applies. If a cause of invalidity partially affects a claim, it is up to the owner to limit it. If the owner does not do so, the judge will have to declare the entire claim invalid.³⁹

12.4.2.2 The ex tunc effects of invalidation

Article 104(1) of LP-2015 provides that:

A declaration of invalidation shall imply that the patent has never been valid and that neither the patent nor its original application have had any of the effects provided for in Title VI of the present Law, to the extent that invalidation has been declared.

Without prejudice to compensation for damage and prejudice that may be due when the owner of the invalidated patent has acted in bad faith, according to Article 104(3) of LP-2015,

The retroactive effect of invalidation shall not affect the following:

1. a) Decisions on infringement of the patent that have become res judicata and have taken place prior to the declaration of invalidation.
2. b) Contracts concluded before the declaration of invalidation, to the extent that they were executed prior to the declaration. However, for reasons of equity and to the extent justified by the circumstances, restitution of the amounts paid under the contract may be claimed.

Once it has become final, the declaration of invalidation of a patent shall become res judicata in respect of all persons.⁴⁰