Applying the ordinary-meaning rule to Liebel-Flarsheim’s patent, the Court found the meaning of the claim terms to be unambiguous. That being the case, the Court found no need to consider whether the resulting construction might also render the patents invalid.
In addition to clarifying when to apply the axiom regarding preserving patent validity, the Liebel-Flarsheim case provided the Federal Circuit with a chance to underscore the prohibition of importing limitations from the specification into the claims. The specification of Liebel-Flarsheim’s patent described several preferred embodiments, all of which had pressure jackets surrounding the claimed syringes. After seeing the defendant’s products in the marketplace, the patentee attempted to claim its invention more broadly to include syringes without pressure jackets. The district court, focusing on the written description, held that the claims inherently required the pressure jackets described in the specification.
In reversing the district court, the Federal Circuit stated that because the specification did not clearly disavow the broader scope implicit in the plain meaning of the claims, it was improper for the district court to import that limitation into the broader claims. The Court noted that whether the broadly construed claims would be invalid should not have been taken into consideration in construing otherwise unambiguous claims. The Court also further noted that there was nothing necessarily improper in amending pending claims to cover newly discovered competitive products.
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