Patent claim construction in Australia: Federal Court confirms the need for careful consideration of the use of “comprising” and “contains” in patent claims

In contested patent proceedings in Australia the interpretation of claim features that are introduced using the words “comprise” or “contain” is frequently in issue. An August 2017 decision of the Federal Court is an example in which the interpretation adopted was determinative in a finding that a patent was not infringed.

The decision reconfirms that it is important for patent applicants to carefully consider the use of claim terms like comprise and contain, which can be construed in either an exhaustive or an inclusive sense. In particular, if the claims use these terms, then patent applicants should actively manage the risk of an unfavourable interpretation.

Introduction: two possible meanings of “comprises” and “contains”

The Australian Patent Office Manual of Practice and Procedure provides guidance to examiners on how to interpret the words “comprises” and “contains” in an integer of a claim.¹ For example an integer of a claim may be in one of the following forms:

A component X comprising features Y.

A component X containing features Y.

The manual identifies that both “comprises” and “contains” are susceptible to:

An exhaustive meaning whereby component X has only features Y; and

An inclusive meaning whereby component X has features Y and may have other features.

Examiners are instructed to interpret these words having regard “to the context of its use”. In particular, the Manual specifies that it is relevant to consider whether the advantages of the invention arise only from the specified features and whether the specified features are the predominant feature of that integer of the claim.

The inclusive meaning is clearly broader than the exhaustive meaning. For this reason it is often the subjective intention of the patentee that an inclusive meaning be adopted. Subjective intention is however irrelevant, as claim construction is an objective exercise.

Infringement case fails at first instance due to use of “contains” in an exhaustive sense

In an August 2017 first instance decision, the Federal Court gave an exhaustive interpretation to an integer of a claim to a light emitting diode (LED). As a direct consequence of this, the claim for infringement failed.²

The claim specified that a phosphor component of the LED contains a category of fluorescent material. The court interpreted “contains” in an exhaustive sense. The claim for infringement consequently failed, as the alleged infringing LEDs contained not only fluorescent material within the defined category, but also other fluorescent material not within the defined category.

In its reasons the Court referred to the following considerations:

• The problem that the inventors addressed can be attributed to the characteristics of fluorescent materials used in prior art devices.
• The disclosed invention is to use of a particular category of fluorescent materials and twelve examples were provided, all using only one or two fluorescent materials in the category. Two comparative examples were given that did not use a fluorescent material in the category.
• The specification said nothing about the use of other materials and could make no promises as to their characteristics when used in a LED.
• Each consistory statement for the claim “describes the phosphor as a fluorescent material of the stated formula” (italic emphasis in original) and “do not even suggest, let alone say, that the phosphor can be anything other than the specifically stated fluorescent material defined by the general formula”.

Thus it can be seen that the interpretation exercise was a matter of some complexity. Complexity gives rise to uncertainty. The patentee advanced several arguments in support of an inclusive interpretation of “contains”, but these were not found persuasive

Lessons for Australian practice

The decision of the Federal Court adds to a line of cases that consider whether integers of a claim are exhaustive or non-exhaustive. Ignoring the issue and its development in Australia is rife with risk.

In an attempt to manage this risk, in recent years it has become common practice for Australian patent specifications to include a definition of “comprises” as having an inclusive meaning. The intent is to forestall an argument that the word should be interpreted in the more narrow exhaustive sense. It is less common for a specification to define “contains”, perhaps because this term less often appears in the claims.

An explicit inclusive definition of claim terms that can have an inclusive or exhaustive meaning may broaden the scope of the claim. However, this approach will need to be tempered in some cases by the need to distinguish prior art. Sometimes both options need to be covered, to best protect the applicant’s position for both infringement and validity.

Each patent application should therefore be individually evaluated. Suitable claim and specification drafting strategies can then be utilized to manage the risk of uncertainty between an inclusive and exhaustive interpretation.