Unity of Invention and Divisional Applications

Legal background

According to Chinese Patent Law a patent or utility model application can only contain one invention or a group of inventions linked by a single inventive concept. The relevant provisions of the Chinese Patent Law are:-

Article 3l.   An application for a patent for invention or utility model shall be limited to one invention or uti1ity model. Two or more inventions or utility models belonging to a single general inventive concept may be filed as one application
     

Rule 35.    Two or more inventions or utility models belonging to a single general inventive concept which may be filed as one application in accordance with the provision of Article 3l, paragraph one of the Patent Law shall be technically inter-related and contain one or more of the same or corresponding special technical features. The expression "special technical features" shall mean those technical features that define a contribution which each of those inventions or utility models, considered as a whole, makes over the prior art.

Chinese Patent Office’s assessment of Unity

Thus a single application can have two or more independent claims, if each independent claim contains the same novel and inventive feature (“special technical feature”) or a non-identical, but corresponding special technical feature. This is very similar to the European Patent Office’s approach to unity of invention.

It is usually possible to have several different categories of claim (method, apparatus, product etc) in the same application, as long as the independent claims share a common novel and inventive feature.

If an independent claim contains two or more alternative technical solutions, then each alternative is examined for unity.

Dependent claims are deemed to have unity with each other unless the independent claim that they refer to lacks novelty or inventive step. In that case the dependent claims will only have unity if they share a common novel and inventive feature (see Example 5 below).

In response to a non-unity objection it is possible to argue that the claims are unified or to amend the claims (e.g. to delete claims or to introduce new unifying technical features). Any deleted subject matter may be made the subject of a divisional application.

Examples

Example 1

Claim 1: A conveyer belt X is characterized in A;

Claim 2: A conveyer belt Y is characterized in B;

Claim 3: A conveyer belt Z is characterized in A and C.

A and B are not known from the prior art. Therefore both claims 1 and 2 are novel and inventive (as is claim 3). A and B are unrelated to each other.

Claims 1 and 3 have unity of invention because they share the same novel and inventive feature A. Claim 2 lacks unity with claims 1 and 3, however, because although claim 2 is inventive it has no inventive feature (special technical feature) in common with claims 1 and 3.

Example 2

Claim 1: A transmitter characterized in that it uses a special signal modulation method X

Claim 2: A receiver characterized in that it uses a special signal demodulation method Y;

Both X and Y are new and inventive. The demodulation method Y is the inverse of X.

X is the novel and inventive (special) technical feature of claim 1 and it corresponds to and has a technical relationship with the special technical feature Y of claim 2. Therefore claims 1 and 2 have unity of invention.

Example 3

Claim 1: A method "B" for making product "A";

Claim 2: A method "C" for making Product "A";

Claim 3: A method D for making product "A".

Compared with the prior art, product "A" is new and inventive. Thus, product "A" is a common special technical feature of all three process claims and methods "B", "C", and "D" possess unity.

If however product "A" lacked novelty, then it could not be regarded as the specific technical feature and the unity of claims 1 to 3 would have to be re-considered (in that case they would only have unity if methods B, C and D had one or more of the same or corresponding novel and inventive process steps).

Example 4

Claim 1: A compound X;

Claim 2: A method of preparing compound X;

Claim 3: The use of compound X as a pesticide.

Situation 1: The compound X possesses novelty and inventiveness. Therefore compound X is a special technical feature present in all three of these claims and claims 1 to 3 have unity of invention.

Situation 2: The compound X does not possess novelty and inventiveness compared with the prior art. The only common technical feature of Claim 2 and Claim 3 is compound X, but compound X is not a “special technical feature” because it is not new and inventive and so makes no contribution to the prior art. Therefore claims 2 and 3 lack unity (even if the method of preparation and the use as a pesticide are themselves new and inventive).

Example 5

Claim 1: An indicator has features A and B.

Claim 2: An indicator as claimed in Claim 1 has another feature C.

Claim 3: An indicator as claimed in Claim 1 has another feature D.

Situation 1: Compared with the indicators disclosed in the prior art, an indicator having features A and B as claimed in Claim 1 is novel and inventive. Claims 2 and 3 have unity because they are dependent claims unified by the features of claim 1.

Situation 2: Due to an obvious combination of two prior art documents, the indicator as claimed in Claim 1 is not inventive. C and D are not disclosed in the prior art and make a contribution over it. C and D have no technical relationship with each other.

In this situation, claims 2 and 3 lack unity because they do not share the same or a corresponding novel and inventive feature. Although claims 2 and 3 have features A and B in common, these features are obvious from the prior art and therefore cannot act as a “special technical feature” to unify the two claims. Put another claims 2 and 3 differ from the prior art in different ways and are therefore different inventions.

Chemical Inventions

The above principles apply equally to chemical inventions. However, the Examiners’ Guidelines, contains the following extra guidance for particular issues, which may arise in applications related to chemical inventions.

Markush claims

A Makush claim is considered as conforming with the requirement of unity if its selectable elements all possess a similar property.

Chemical compounds are regarded as having similar property and the Makush claim to possess unity if the selectable compounds meet the following requirements:

(1) All of the selectable compounds possess the common property or function; and

(2) All of the selectable compounds possess a common structure, i.e., they share a common main structural unit; or under the circumstances that they cannot have a common structure, all of the selectable compounds in the relevant technologies of the invention are regarded as belonging to the same group.

The main structural unit may be the main part of a compound or a part that distinguishes it from the prior art. Compounds are considered to “belong to the same group" if the same results will be achieved after they have been substituted for each other.

Intermediate Products

1.       Intermediate products have unity with the end product if :- (a) the intermediate product and the end product have same basic structure unit, or their chemical structures are technologically closely related and the basic structure unit of the intermediate product goes into the end product; and (b) the end product is directly prepared from the intermediate product or separately from the intermediate product.

2.    Where there are several methods for preparing an end product by different intermediate products, there is unity between these methods only if the different intermediate products possess an identical structural unit.

3.    If the intermediate products have different structures there is no unity. The applicant must choose one and may pursue the others in divisional applications.

Divisional Applications

A divisional application can be filed at any time up until two months after the notice of grant is received on the original application.

The contents of the divisional application may not extend beyond the disclosure of the original application. For purposes of novelty and inventive step, the divisional application claims the priority date of the original application.