Saint-Gobain Adfors S.A.S v 3M Innovative Properties Company

Patent claims must be construed purposively, by asking what the skilled person would understand the words to mean in the context of the specification. A claim involving a question of degree is not insufficient merely because its boundary is fuzzy; uncertainty arises where the correct test for performance cannot be identified. A product claim must be enabled across its whole scope, including materially different values within a claimed range. Routine trial and error is permissible, but the specification must provide a route to success without undue burden. An obviousness case based on a skilled person exploring a multi-dimensional process space fails where the proposed route depends on hindsight selection of a particular combination of conditions.

Saint-Gobain sought revocation of a patent owned by 3M for dish-shaped abrasive particles made from alpha alumina. The patent claimed particles having a recessed face and an average thickness ratio, calculated by measuring fifteen randomly selected dish-shaped particles.

The challenge alleged lack of novelty and inventive step over the earlier Rowenhorst patent, lack of plausible technical contribution, uncertainty-type insufficiency, and undue-burden insufficiency. The central issues were the construction of the claim, whether Rowenhorst inevitably or obviously produced the claimed particles, and whether the patent enabled production across the claimed thickness-ratio range.

1. Construction. The expression “dish-shaped” included both planar/concave and concave/convex particles. The claim required a random selection of fifteen dish-shaped particles and calculation of the thickness ratio by averaging their corner and interior thicknesses. It did not require each individual particle to have the specified ratio. The sample nevertheless had to contain enough dish-shaped particles to permit a genuinely random and representative selection.
2. Novelty and obviousness over Rowenhorst. The evidence did not establish that practising Rowenhorst would inevitably, or even frequently, produce batches satisfying the claim. The obviousness case depended on the skilled person making a particular combination of changes within a multi-dimensional space of process variables. That was a hindsight-driven step-by-step analysis. A skilled person seeking to make Rowenhorst’s flat particles would also discard, rather than sinter, precursor particles which appeared accidentally dished. The claims were therefore not invalid over Rowenhorst for lack of novelty or inventive step.
3. Technical contribution. The patent made plausible, through the ice-cream-scoop theory and the experimental results, a technical benefit for dish-shaped particles compared with essentially flat particles. The thinness theory could not support the whole claim because it depended on absolute interior thickness rather than shape or thickness ratio, but the attack based on lack of plausible technical effect failed.
4. Uncertainty. Whether a particle was dish-shaped involved a permissible fuzzy boundary. The theoretical possibility that different random samples might produce different averages did not establish insufficiency. Practical, material uncertainty had not been proved.
5. Undue burden. The evidence did not show that producing some particles within the claims, or carrying out the measurement test, required undue burden. The position differed across the full claimed range. The specification disclosed production around ratios of 1.55 to 2.32 but gave no adequate route to ratios approaching 5.00. The cross-reference to US 001 could not supplement the disclosure without evidence that the skilled person would consult and use the particular passages relied upon.
6. The patent was insufficient across the scope of claim 1. The subsidiary claims did not avoid that finding. The patent was ordered to be revoked, with the form of order adjourned.