The Intellectual Property Court rendered the 102-Min-Zhuan-Su-96 Civil Decision of January 23, 2015 (hereinafter, the "Decision") to provide detailed explanation about the adoption of evidence, scope of literary interpretation and the principle of estoppel for patent claims construction.

According to the facts underlying the Decision, the Plaintiff owns the invention patent titled "Loading and Unloading Devices for Circuit Components" (hereinafter, the "Patent-in-suit"). The Plaintiff filed a complaint, alleging that the capacitor testers manufactured and sold by the Defendant infringe the Plaintiff's claims in the Patent-in-suit, requesting to desist from such infringement and seeking damages.

According to the explanation in the Decision, the evidence used for constructing patent claims includes internal and external evidence with internal evidence having priority over external evidence. Internal evidence includes the text in the claims, descriptions of inventions or utility models, drawings and files and materials such as the prosecution history, which includes documents and files other than the original specification in the course of patent prosecution and maintenance. For example, the supplements, modification documents, correction documents, replies, responses, reasons or other relevant documents in the course of prosecution, opposition, invalidation or administrative remedies. It was further pointed out in the Decision that explaining the technical features of the Patent-in-suit should cover the descriptions in the specification that correspond to the essential structures, materials, steps and scope of equivalents required to complete such functions, provided that this is not limited to the embodiment examples set forth in the specification. In additional to the components and structures corresponding to such functions in the specification, the explanation of technical features should also include the connection relations between components without which the functions defined in the claims cannot be achieved. Therefore, literary interpretation should include the structures of the essential components and their connection relations required to complete the functions.

It was further expounded in the Decision that the so-called "principle of estoppel" in prosecution history means that if the scope of a patent is reduced as a result of any supplements, modifications, amendments, replies and responses with respect to patent claims, the portions which have been previously limited or excluded by the patentee shall not be re-asserted in a subsequent patent infringement lawsuit. The principle of estoppel can be asserted as a defense against the construction of patent claims and the doctrine of equivalents and should be asserted by the defendant who should assume the burden of proof.

After the above specific principles for patent claims construction were laid down in the Decision, it was held that the means of the Patent-in-suit are functional expressions. After the patent claims were constructed with the technical features of the products at issue compared, the products at issue do not fall within the literary interpretation of the scope of equivalents of the technical features. Therefore, they do not fall within the claims of the Patent-in-suit and do not infringe the Plaintiff's Patent-in-suit. The Plaintiff's complaint was rejected.