3.5. Different descriptions

In T 2563/11 the appellants had contended that the prohibition on double patenting did not apply because, despite their identically worded independent claims, the parent patent and the divisional application had different descriptions and so each conferred a different extent of protection under Art. 69 EPC. The board observed, however, that the important point for the purposes of the prohibition on double patenting was whether the "same subject-matter" was claimed. A claim's subject-matter was defined by its category and technical features (Art. 84 EPC and R. 43(1) EPC), so the description was irrelevant in establishing whether the same subject-matter was claimed, especially if the claims in question were anyway clear and understandable in themselves (see T 197/10). By contrast, while the claims were likewise the basis for determining the extent of protection conferred by a European patent, Art. 69(1) EPC provided that the description and drawings were to be used to interpret them for this purpose. This meant that the extent of protection conferred by the patent might be broader than the subject-matter claimed. That what mattered was not the extent of protection that the application being examined would confer as compared to the already granted patent but instead what subject-matter was claimed in each case ("protected subject-matter") was in line with G 1/05 (point 13.4 of the Reasons) and e.g. T 2461/10 (point 16 et seq. of the Reasons) and T 879/12 (points 7, 10 and 14 of the Reasons).