T 0068/85 - Allowability of functional features ("Synergistic herbicides") - #37

Citation rank: 37
No. of citations: 112

T 68/85 is concerned with the conditions under which functional features are allowed in patent claims.

Claim 1 in the underlying examination case related to: "An agent for selective weed control based on a mixture of [a substance II with a substance Ia or Ib] in a quantity producing a synergistic herbicidal effect."

A synergistic effect of substance II with substances Ia or Ib was demonstrated in the application as filed, albeit only within relatively narrow concentration ranges.

The Examining Division had refused the patent application for lack of sufficient disclosure (Art. 83 EPC). They were of the opinion that the skilled person "could not prepare mixtures that were genuinely synergistic ... without knowing the range of ratios in which ingredients had to be mixed". And further, in the eyes of the Examining Division, it had "not been demonstrated that the synergistic effect ... occurred throughout the claimed range".

The applicant filed an appeal against the refusal.

The Board in T 68/85 did not find the Art. 83 objection justified. They stated that the patent application as a whole must contain sufficient information to make the claimed synergistic mixtures of substance II with substances Ia or Ib, and suitable weight ratios were disclosed in the description.

Regarding the presence of a functional feature in claim 1 (i.e., "... in a quantity producing a synergistic herbicidal effect"), the Board noted:

"However, the applicant cannot simply define a feature in a claim as he wishes; he must choose the form that is objectively more precise (T 14/83). This requirement is met in the present case as the Board does not see how the limits within which the two herbicide couples combine to give a synergistic effect could be defined more precisely than has been done without limiting the scope of the invention. Accepting the Examining Division's suggestion and including in Claim 1 [specific concentration ranges of substances II and Ia or Ib] so as to render the former more precise would mean limiting the scope of the invention unjustifiably to a particular range of weight ratios and thus unacceptably restricting protection to only part of the invention as disclosed." (point 8.4.2 of the reasons)

However, the Board also noted that a claim may not include a functional feature, if

"... it jeopardises the clarity of a claim as required by Article 84 EPC. That clarity demands not only that a skilled person be able to understand the teaching of the claim but also that he be able to implement it. In other words, the feature must provide instructions which are sufficiently clear for the expert to reduce them to practice without undue burden, if necessary with reasonable experiments."

The Board thus examined whether the application included sufficient information for the skilled person to make synergistic mixtures of substances II and Ia or Ib for the relevant combinations of crops to be protected and crops to be decimated. The Board noted in this regard that the application disclosed specific examples of synergistic concentration ranges, which the skilled person could use as guidance or starting points. The application also disclosed reproducible test methods to establish whether synergistic effects were present. The test methods even allowed to quantify the synergistic effect. The Board observed that the tests were cumbersome (because seeds had to first germinate, before an effect could be observed), but this would be reasonable; in fact usual in the field of herbicides. Therefore the use of a functional feature to functionally express the weight ratios of the synergistic compounds in the mixture was considered to be in accordance with Art. 84.

Finally, the Board also regarded the claimed synergistic mixtures inventive over the prior art. The case was hence remitted to the Examining Division with the order to grant a patent.

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Headnote:

Functional features defining a technical result are permissible in a claim, if from an objective viewpoint, such features cannot otherwise be defined more precisely without restricting the scope of the invention, and if these features provide instructions which are sufficiently clear for the expert to reduce them to practice without undue burden, if necessary with reasonable experiments.

The full text of the decision can be found here.

Quotes from decisions citing T 68/85 can be found here.