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Independent and dependent claims

2.45 Claims can either be independent or dependent. Generally an independent claim is one that does not refer to any other claim. Some independent claims may refer to other claims. For example, in chemistry, an independent claim appended on another claim may be encountered. It stands alone in defining the invention or an aspect of it. An independent claim is not necessarily the broadest claim in the application, but the broadest claim in an application is normally an independent claim. This is because there may be numerous independent claims, each covering a different aspect of the invention.

2.46 A dependent claim can depend upon one or more independent claims or one or more dependent claims. It should be noted that while some countries will not allow multiple dependent claims (that is, claims that are dependent on several claims), these are allowed under the Singapore law. Singapore law also allows claims to be dependent on multiple dependent claims. Examples of multiple dependent claims are:

“The method of claim 1 or 2, further comprising …”

“The process of any of claims 1-4 …, comprising …”

“The composition according to any one of the preceding claims, wherein …”

2.47 Furthermore, a claim may refer to a later claim or claims rather than a preceding claim or claims. In most cases this may be due to an error in drafting and the Examiner may, as a matter of courtesy, bring it to the attention of the applicant. However, unless the error results in a lack of clarity, no objection is necessary.

2.48 Independent claims should define all of the essential features of an invention. Generally, the preamble will indicate the subject matter of the claim:

“A compound of Formula I …” (the subject is a compound)

“A method of preparing article X …” (the subject is a method)

“An apparatus comprising …” (the subject is an apparatus)

2.49 Claims which are appended to another claim will generally import all of the features of the claims to which they are appended, and serve to narrow the scope of the claim, for example:

1. An apparatus comprising component A and component B.

2. The apparatus of Claim 1 wherein component B is an in-line filter.

2.50 In this case Claim 2 is dependent on Claim 1 and all of the features of Claim 1 are imported into Claim 2. The scope of the claim is then narrowed to the apparatus in which component B is a particular embodiment.

2.51 In contrast, the following claim, while appended is not truly dependent.

1. A method of preparing Article X comprising the steps of …

2. Article X as defined in Claim 1 having features …

In this case the preamble of Claim 2 suggests that the claim is directed to the article per se and not to the process of making the article. This appendence does not import the features of Claim 1 (in this case the steps of the method), and may simply be a shorthand way of defining the article without reiterating matter that has already been defined in the previous clam (for example in the case of chemicals, it might avoid redefining large numbers of substituents). This claim is not dependent despite the fact that it is appended to Claim 1. Furthermore, this impacts on the scope of the search since a search of Claim 2 would not necessarily be limited to the features defined in Claim 1.

2.52 Other examples of this type are the following:

1. Process for the preparation of compounds of Formula X wherein R is alkyl, halo or aryl comprising the steps of …

2. Compound of Formula X wherein R is halo or aryl.

In this case the inventor has found a new way of preparing compounds of Formula X and has claimed it for the preparation of compounds of Formula X wherein R is alkyl, halo or aryl. Claim 2 appears to be directed to a subgroup of compounds of Formula X – presumably the inventor considers these are novel and is seeking to claim the compound per se. The search in this case would need to cover both the general preparation, as well as the compounds of Formula X having R as halo and aryl.

2.53 In the following case:

1. Apparatus comprising component A and component B.

2. Component B as defined in Claim 1 comprising …

Claim 2 would be interpreted as having a kind of “partial dependency” where the claim is directed to component B only and would not include component A. A search would need to cover both the apparatus of claim 1 and the component B of claim 2.

2.54 In some cases, a dependent claim will include embodiments that do not fall within the scope of the claim to which it is appended. This situation can often occur in the chemistry area where a novelty objection results in amendment of the independent claim to remove some matter, but the dependent claim is not amended accordingly to remove specific embodiments. In such cases a clarity objection will probably be required.

2.55 A similar situation occurs where a claim that appears to be dependent removes a feature, for example:

1. A composition comprising A, B and C.

2. The composition of Claim 1 wherein C is absent.

In this case, Claim 2 is actually broader than Claim 1. However, this may not be objectionable since it is not mandatory that the broadest claim be the first claim. Indeed in some cases the broadest claim may be a later claim. The key consideration when determining whether an objection is required will be whether the person skilled in the art could readily ascertain the scope of the claim. Full support will be a consideration – is component C indicated as being essential to the invention, or merely optional? Are there inconsistencies between these and other claims that result in a lack of clarity as to the scope of the claims? In any case, the Examiner will also need to ensure that the search covers the broadest claim.