University of Queensland v Siemens Magnet Technology Ltd & Anor

Patent claims must be construed in their context, beginning with the words chosen by the patentee. A technically arbitrary limitation may receive a broader contextual meaning where the specification indicates that strict compliance was not intended.

For added matter, the comparison is between the disclosure of the application as filed and the disclosure of the patent as granted. Subject matter is added unless it was clearly and unambiguously disclosed, expressly or implicitly, in the application as filed.

For obviousness, the court identifies the inventive concept, adopts the viewpoint of the normally skilled but unimaginative person, identifies the differences from the prior art, and asks whether those differences required invention. Claims covering an obvious product cannot be saved by a non-obvious design method unless they are limited to that method.

The claimant alleged infringement of UK patent GB 2 308 451, concerning superconducting magnets for magnetic resonance imaging. The defendants denied infringement and counterclaimed for revocation on grounds including added matter, obviousness and insufficiency.

The dispute concerned, among other matters, the construction of the expressions “common inner radius” and “prior to shimming”, the scope of direct and indirect infringement, and whether the claimed magnet configurations were disclosed or rendered obvious by the prior art, particularly the US patent referred to as Ohta.

The court also considered whether the claims impermissibly introduced a feature absent from the application as filed.

The action failed and the counterclaim succeeded. The patent was revoked.

1. Construction. The phrase “common inner radius” was construed contextually as meaning a generally cylindrical configuration, rather than requiring exact equality of the radii. The phrase “prior to shimming” referred to the theoretical design of the magnet, while the claim also required the actual system, in use, to produce a substantially homogeneous field over the specified volume. The claim was therefore directed to a physical magnetic resonance system incorporating a magnet with the stated design features.

2. Infringement. Testing a magnet with test equipment did not produce a “magnetic resonance system”, because the assemblage merely measured its own magnetic field and did not measure an external subject or produce an image. The OR76 could satisfy the relevant design requirement, but did not directly infringe during testing. Supply of means under section 60(2) of the Patents Act 1977 required knowledge, or obviousness to a reasonable person, that the means were suitable for and intended to put the invention into effect in the United Kingdom. The OR122 did not meet the homogeneity requirement. The Magnetom Espree infringed claim 18, subject to the patent’s validity.

3. Added matter. Applying the three-stage comparison identified in Bonzel v Intervention (No 3), the application as filed did not disclose that the coils possessed a common inner radius. That feature was disclosed in the granted patent. It therefore constituted added matter, and the claims could not be amended to remove it because that would extend their scope.

4. Obviousness. Applying the Windsurfing International checklist, the inventive concept was the addition of at least one oppositely wound coil to shorten a magnet while maintaining homogeneity. Starting with the well-known Garrett design and applying Ohta’s teaching made claimed arrangements obvious. The claims were consequently invalid independently of the added-matter objection.

5. It was unnecessary to decide insufficiency in detail. Claims covering the product were too broad to rely on the non-obviousness of the simulated-annealing design method.