Feynman LIANG Patent & Trademark Attorney	Published on April 8, 2020

In the case Shijiguangsu vs. Baidu, both the Beijing IP Court (1st instance court) and the Beijing Higher People’s Court (final instance court) determined the feature defined by functional expression as non-functional feature, leading to a definite scope in the claim construction. As a common practice, apparatus claims, system claims, computer readable medium claims etc. correspondent to process claims are usually included in the claim set of a computer software patent. The case provides an example of logical steps in claim construction of claims involving feature defined by functional expression commonly found in the apparatus claim.

Back in 2015, Shenzhen Shijiguangsu Information Technology Co., Ltd. (‘Shijiguangsu’) as the exclusive licensee of the patent No. ZL200610061369.9 filed a lawsuit against Baidu Online Network Technology (Beijing) Co., Ltd. (‘Baidu’) for patent infringement. The patent at issue is entitled “System and method for updating Chinese lexicon”. Claim 1 of the patent reads as follows.

System for updating Chinese lexicon,

the said Chinese lexicon being connected to the Chinese input module and including a core dictionary and a user dictionary located in the terminal device,
characterized in that it also includes a synchronization module located in the terminal device and connected to the server through a network,
the server being used to store dictionary data of the user account corresponding to the user dictionary,
the synchronization module maintaining synchronization between the user dictionary and dictionary data corresponding to user accounts in the server.
As indicated above, independent claim 1 is a apparatus claim that merely references claim 7 which is an independent process claim.

One of the focuses of the claim construction in the proceedings is on the feature “the synchronization module maintaining synchronization between the user dictionary and dictionary data corresponding to user accounts in the server”. The feature “the synchronization module” is not a physical device. Instead, it is defined by the functional expression “synchronization between the user dictionary and dictionary data corresponding to user accounts in the server”.

1.Functional feature or not?
The defendant held that this feature of functional expression should be deemed as a functional feature and therefore the scope of the feature should be defined strictly by the embodiment of the physical “module” and its equivalence in the specification.

Both the Beijing IP Court and the Beijing Higher People’s Court disagreed with the defendant and determined that this feature defined by functional expression was a non-functional feature with the following reasons.

The Interpretation of the Supreme People's Court on Several Issues Concerning the Application of Law in the Trial of Cases Involving Patent Infringement Disputes (2016) includes an exception where a technical feature being defined by functional expression will not be found functional, provided that "a specific embodiment for achieving the above functions or effects can be directly and specifically determined by those ordinary in the art only by reading the claims".

When a claim includes recitation of function or effect, if the embodiment corresponding to the function or effect can be realized directly and specifically through reading the claim by those ordinary in the art, this technical feature should not be deemed as “functional feature”.

In this case, “synchronization” is a common terminology widely used in the industry. By reading the claim, those ordinary skill in the art are able to directly and specifically confirm the embodiment of synchronization module for synchronization of database between the server and the user terminal as follows:

Update the data of user terminal based on the data of the server, or update the data of the server based on the data of the terminal, so that these two sets of dictionary data remain consistent and updated.

It is known to those ordinary in the art that there are more than one possible embodiment of synchronization available. However, the only parameter set forth in the judicial interpretation above is “directly and specifically confirm the embodiment” without further requiring that there should be only one possible embodiment available.

Therefore, this technical feature “synchronization” fulfils the parameter of the exception in the judicial interpretation and it should not be deemed as “functional feature”.

2.Scope of protection
It is provided in Article 4 of The Interpretation of the Supreme People's Court on Several Issues Concerning the Application of Law in the Trial of Cases Involving Patent Infringement Disputes (2009) that, for the technical features expressed in terms of functions or effects in the claims, the people's court shall determine the content of the technical features in conjunction with the specific embodiments of the functions or effects described in the specification and the drawings and their equivalent embodiments.

Since the feature “synchronization module” is not a “functional feature” as provided by the judicial interpretation above, the scope of the technical features should not be construed based on the specific embodiments of the functions or effects described in the specification and the drawings and their equivalent embodiments.

The Patent Examination Guidelines further provided that, if an apparatus claim is drafted on the basis of computer program flow completely and accordingly to the way completely identical with and corresponding to each step in the said computer program flow, or according to the way completely identical with and corresponding to the process claim reflecting the said computer program flow, ie. each component in the apparatus claim completely corresponds to each step in the said process claim, then each component in the apparatus claim shall be regarded as function modules which required to be built to realize each step in the said computer program flow or each step in the said method.

Since claim 1 is a apparatus claim defined by the synchronization module as the function module, the scope of the feature should be defined by the correspondent steps recited in the disclosure.

Both the Beijing IP Court and the Beijing Higher People’s court referred the scope of “synchronization module” to the decision of Patent Review Board in the previous invalidity case involving the same patent. According to the decision,“synchronization module” should be specifically limited to" detect whether the dictionary data of the server and the terminal are consistent; when the data is inconsistent, it will be determined according to the specific situation of the data inconsistency whether to update from the server to the terminal or from the terminal to the server, update according to the determination result, so that the dictionary data remains consistent."

In the proceedings, the infringement analysis was carried out based on the scope of the claim construed as a result of the conclusion above.

From the case above, it is indicated that the court construes the apparatus claim involving functional expression in the following ways.

1. Determine if the embodiment corresponding to the function or effect expression can be realized directly and specifically through reading the claim by those ordinary skill in the art.

If yes, the feature should be deemed as “functional feature” and the scope of protection is defined narrowly by the embodiments of the apparatus/module and their equivalence in the specification.

If no, go to the next step

2. The scope of the module feature in the apparatus claim is defined by the step of process as recited in the description.

If the feature is determined by the court as functional feature, the scope of protection is inevitably narrowed to embodiment of the apparatus/module and its equivalence recited in the disclosure. In some extreme cases where embodiment is absent in the specification, the claim would be determined as indefinite, leading to failure of infringement analysis (just like in the Nokia v. Huaqin). To avoid the situation, the claim should be drafted in the way that the embodiment correspondent to the function expression be realized directly and specifically through reading the claim by those ordinary skill in the art.