As a patent attorney, I am often asked the question – ‘shall I draft my own patent specification?’ Of course, my answer is ‘no’. There are lots of reasons for this. One of which is that the particular way in which a patent specification is drafted, including the specific words used in the claims to define the scope of your invention, and how the body of the specification supports the claimed scope of protection is crucial when it comes to validity and enforcement.

As reported in our earlier article regarding Nichia Corporation v Arrow Electronics, the primary judge found that Arrow Electronics did not infringe Nichia’s patent based on the interpretation of the word ‘contains’ in the claims. The appeal of this decision was recently dismissed with the Full Court confirming the findings of the primary judge on issues relating to claim construction and infringement.

Claim 3 being the relevant claim of Nichia’s patent defined:

A light emitting device…wherein the phosphor contains fluorescent material represented by a general formula (Rel-rSmr)3(Al1-sGas)5O12:Ce, where 0≤r<l and 0≤s≤1 and Re is at least one selected from Y and Gd. (emphasis added).

The question mainly centered around whether the word ‘contains’ should be construed in the exhaustive sense or the inclusive sense. For example, if I say that my lunch contains a sandwich, there are two possible scenarios for the contents of my lunch:

  1. My lunch only contains a sandwich and nothing else (exhaustive interpretation); or
  2. My lunch contains a sandwich and some other food items, such as fruit, chocolates and various other snacks (inclusive interpretation).

The Court confirmed the primary judge’s finding that the word ‘contains’ in claim 3 should be construed in the exhaustive sense to mean that the fluorescent material must be the fluorescent material represented by the general formula and not that fluorescent material together with some other fluorescent material not represented by the general formula.

In arriving at this conclusion, the court considered a range of arguments for construing the word ‘contains’ in an exhaustive and in an inclusive sense, and found both sides of the argument to be fairly balanced. Moreover, the dependent claims (including claim 6 which specified that the phosphor contains two or more fluorescent materials of different compositions represented by the general formula) could be construed consistently with either construction.

However, the Court noted that the specification does not mention, in the context of the invention, any phosphors other than those containing the fluorescent material of the kind described in the claims, and that the specification is silent about the possibility of the fluorescent material containing those of the kind described in the claims together with any other kind.

Consequently, infringement was not established as Arrow’s LEDs included a fluorescent material which was within the general formula and other fluorescent material that was not within the general formula.

As is evident from this case, words such as ‘contains’, ‘includes’ and ‘comprises’ may be ambiguous without context. It is therefore important for the body of the specification to clarify the intended meaning. If an inclusive interpretation is desired, the specification should specifically mention this and provide example embodiments to support this construction, even if those example embodiments do not necessarily embody the commercial product.