Method for Manufacturing Smooth Metal-shield Composite Belt

Xi’an Qinbang Telecommunication Material Co.,Ltd. v. Wuxi Longsheng Cable Material Factory et.al. – How to Interpret Inconsistent Claims with Detail Specifications (Civil Judgment (2012) Min Ti Zi No.3 by the Supreme People's Court on August 24, 2012)

Obvious drafting mistakes in the claims of a granted patent do not inevitably render the patent invalid. If those skilled in the art upon reading the claims, can immediately realize that there is an obvious mistake in a particular claim and can determine its exclusive and correct meaning in light of the patent specification, the scope of the claim shall be determined based on the corrected understanding. However, if the language of the claim is clear, even if inconsistent with the specification, the claim shall be construed as it would be understood by those skilled in the art, rather than based on the specification.

Xi’an Qinbang Telecommunication Material Co.,Ltd. (hereinafter referred to as “Qinbang”) is the patentee of Chinese Invention Patent No. ZL01106788.8 titled “Method for Manufacturing Smooth Metal-shield Composite Belt.” Qinbang brought a patent infringement lawsuit to the Xi’an Intermediate People’s Court against three defendants including Wuxi Longsheng Cable Material Factory (hereinafter referred to as “Longsheng Factory”) and other two entities, claiming monetary damages and injunctions.

Claim 1 of the patent involved is reproduced in part as follows:

“1. A method for manufacturing smooth metal-shield composite belt, comprising adhering a plastic thin film to a metal foil surface in an uneven and non-planar manner to form point contacts between the composite belt and a longitudinal wrapped or sizing mold of an optical cable or electric cable, such that friction force can be reduced, and bumps, air-leakage, mold release and belt breakage of the cable can be prevented, the process and conditions of the method are as follow: ..., (2) transferring a plastic melt or plastic film through a fine meshed steel roller and a squeeze roller rotating with respect to each other, such that there is formed an uneven and rough surface with a thickness of 0.04-0.09 mmon the surface of the plastic film, which is thermally extruded on one side of a substrate facing the metal foil, wherein the steel roller is at a temperature of 35?C-80?C, has a diameter of f240mm-f600mm and a mesh number of 40-85, and wherein the squeeze roller has a diameter of f160mm-f480mm; ....”

The court of first instance appointed an appraisal organization to conduct a technical appraisal, in order to determine whether the manufacturing method of aluminum-plastic composite belt of Longsheng Factory and the technical features of the above patented method are identical or equivalent to each other. Regarding the technical feature “there is formed an uneven and rough surface with a thickness of 0.04-0.09 mmon the surface of the plastic film,” the appraisal report asserted this technical feature means the thickness of the plastic thin film is from 0.04 to0.09 mm, while the product manufacturing method of Longsheng Factory produces a plastic film having a surface roughness of Ra2.47mm to3.53mm and a thickness of 0.055-0.070mm. Accordingly, the appraisal opinion asserted these two features are equivalent to each other. The court of first instance decided Longsheng Factory constituted an infringement, and shall compensate Qinbang for RMB 3,000,000 (around USD 500,000).

Longsheng Factory and the other defendant unsatisfied with the judgment rendered by the court of first instance, and filed an appeal with the Shanxi High People’s Court (“the court of second instance”). The court of second instance affirmed the original judgment upon trial. Longsheng Factory was still not satisfied with the judgment of the court of second instance, and filed to the Supreme People's Court for a retrial. The Supreme People's Court directed the court of second instance to conduct the retrial. The court of second instance upheld the original judgment upon retrial.

Longsheng Factory and the other appellant filed to the Supreme People's Court for retrial again, and submitted that the feature “there is formed an uneven and rough surface with a thickness of 0.04-0.09 mmon the surface of the plastic film” recited in claim 1 refers to the thickness of the uneven and rough layer on the plastic film surface, instead of the overall thickness of the plastic film, i.e. there is formed a concave-convex surface structure of 0.04-0.09mm(40µm-90µm) on the surface of the plastic film. Regarding the feature “there is formed an uneven and rough surface with a thickness of 0.04-0.09 mmon the surface of the plastic film,” the Supreme People's Court found that a person of ordinary skill in the art would construe it’s meaning as the thickness of the uneven and rough surface on the plastic film surface being 0.04-0.09mm. The meaning of this feature is clear and definite. If the feature “there is formed an uneven and rough surface with a thickness of 0.04-0.09 mmon the surface of the plastic film” is interpreted as the thickness of the plastic film being 0.04-0.09mm, the modifiers of “surface,” “rough surface,” and so on in this feature will actually become redundant. Moreover, since the specification of the present patent describes the technical solution in a very simple way, those skilled in the art after reading the claims and the specification, would not come to the conclusion that this feature should be understood as the thickness of the plastic film being 0.04-0.09mm. The surface structure (with a roughness of Ra l.8µm-5µm) of the plastic film used by Longsheng Factory is very different from the concave-convex surface structure of 0.04-0.09mm(40µm-90µm) formed on the surface of the plastic film in claim 1. These two features are neither identical nor equivalent to each other.

Finally, the Supreme People's Court reversed the judgments of the first instance, the second instance and the retrial, and amended the judgment to reject the claims of Qinbang Corporation.

Remarks

As a guiding principle, Article 56 of the Chinese Patent Law (2001) provides that the extent of protection of the patent right for invention or utility model shall be determined by the terms of the claims. Accordingly, the meaning of the claim language shall be ascertained in view of the application’s specification from the perspective of those skilled in the relevant art. Particularly, to ascertain the meaning of a term in the claims, a variety of sources may be adopted, among which the words of the claims themselves can be highly instructive, and the specification in most cases is the best source for discerning the proper context of claim terms.

To determine whether a disputed term in the claims is an apparent mistake, this judgment of the Supreme People's Court provided a two-step test. First, if those skilled in the art can definitely determine the meaning of the disputed term in the claims, the claims shall be construed as they would be understood by those skilled in the art, and the specification shall not be used to contradict the meaning of the term in the claims, even if such meaning is inconsistent with the specification. Second, in contrast, if those skilled in the art upon reading the description and the drawings, can immediately realize that the disputed term is an apparent mistake and can directly, unambiguously, and exclusively ascertain the correct meaning of the term according to the description and the drawings, the particular claims in which the disputed term appears shall be construed so as to be consistent with the description and drawings.

In this case, it is very important to determine whether there is an apparent mistake in the feature “there is formed an uneven and rough surface with a thickness of 0.04-0.09 mmon the surface of the plastic film” of claim 1, i.e., whether the “thickness of 0.04-0.09 mm” in the claims refers to the overall thickness of the plastic film or the thickness of the uneven and rough layer on the plastic film surface. The patentee asserted that this feature should be understood as defining the thickness of the plastic film itself, since each of the numerical values “0.04mm,” “0.09mm,” and “0.07mm” appeared in the embodiments in the patent description represents a respective thickness of the plastic film. Upon reading the written description, there may be a doubt as to whether the term “a thickness of 0.04-0.09 mm” in claim 1 corresponds to the thickness values of the plastic film (0.04mm,0.09mm,and0.07mm) provided in the description such that the above feature should be regarded as having an apparent mistake. An apparent mistake in a claim means that a term in the discussed claim can be directly determined to be erroneous and then unambiguously corrected by a person of ordinary skill in the art in the context of the original description and claims, and thus cannot be interpreted in any other plausible way. However, from the specification disclosure, it cannot be unambiguously determined that the above feature means “the thickness of the plastic film is 0.04-0.09mm.” In contrast, according to the claim language, it is clear that the “thickness of 0.04-0.09 mm” should be interpreted as the thickness of the uneven and rough layer on the plastic film surface. Therefore, the feature “there is formed an uneven and rough surface with a thickness of 0.04-0.09 mmon the surface of the plastic film” of claim 1 cannot be regarded as an apparent drafting mistake in the claims and then be corrected based on the description, but shall be construed according to the words of the claims themselves.

From the teaching of this decision, several measures may be taken during drafting and examination of a patent application to reduce the ambiguities in subsequent litigation of the issued patent. In order to obtain a broad and reasonable patent right, the applicant should clarify the scope and meaning of the claims at the application stage as clear as possible, rather than attempting to resolve the ambiguity in litigation later. Generally, the usage of a term in one claim can often illuminate the meaning of the same term in other claims, and each term in the claims has its respective meaning and cannot be regarded as redundant. Therefore, the applicant should carefully adopt terms and features used in the claims when drafting the application document, such that identical terms are used for the same meaning and different terms are used for different meanings, thereby avoiding claim indefiniteness issue resulted from literal conflict or inconsistency between the claims and the description.