The Court Overturns CNIPA’s Determination on the Written Description Requirement for Parameter Limits
Date: 20 September 2024
【Volume 143】
The Beijing Intellectual Property Court and the Supreme People’s Court of China recently overturned the decision of the China National Intellectual Property Administration (CNIPA) regarding the written description requirement for parameter-limited features in the invalidation case of mobile terminal glass panel patent owned by Corning (Shanghai) Co., Ltd. This case revolves around whether the specification of a patent with parameter-limited features meets the requirement of sufficient disclosure. It provides a typical example that is highly valuable for reference.
Case facts
An anonymous natural person filed an invalidation request against the invention patent titled “ION EXCHANGED GLASSES VIA NON-ERROR FUNCTION COMPRESSIVE STRESS PROFILES” owned by Corning (Shanghai) Co., Ltd. (hereinafter referred to as “Corning”) with Publication No. CN104870393B (hereinafter referred to as “the ‘393 patent”). The CNIPA rendered a decision of partial invalidation of the patent rights (Invalidation Decision No. 45834). In the invalidation decision, the CNIPA dismissed the argument raised by the invalidation requester regarding insufficient disclosure of part of the specification related to the “frangibility design” of the glass. Dissatisfied with the result of the invalidation decision, the requester filed an administrative lawsuit with the Beijing Intellectual Property Court.
The Beijing Intellectual Property Court (first instance) overturned the decision of the CNIPA ((2020) Jing 73 Xing Chu No. 15733 Judgment) and ruled that the entire patent was invalid. Corning (the patentee) subsequently appealed to the Supreme People’s Court. In February 2024, the Supreme People’s Court of China upheld the first-instance judgment ((2022) Zui Gao Fa Zhi Xing Zhong No. 361 Judgment), dismissing Corning's appeal.
Technical Content of the ‘393 Patent and Issues
This patent relates to chemical products and preparation methods thereof, with Claim 1 claiming a type of strengthened glass..
Claim 1 specifically limits the glass to simultaneously satisfy the following two conditions:
(1) The central tension (CT) is greater than -37.6ln(t) (MPa) + 48.7 (MPa);
(2) The glass with the CT value described in (1) is not frangible (i.e., below the frangibility limit).
Above all, the main issue is whether the description of “below the frangibility limit” in condition (2) meets the requirement of sufficient disclosure.
Opinion of the China National Intellectual Property Administration
The Beijing Intellectual Property Court and the Supreme People’s Court held that:
The specification of the ‘393 patent does not disclose the frangibility test results that would demonstrate the glass is not frangible. Even though frangibility testing methods are known in the art, the specification of the ‘393 patent does not disclose the frangibility test results for the glass in the embodiments described in Figures 5-8 of the specification, making it impossible to prove that the ‘393 patent achieves the technical solution defined in Claim 1. Therefore, the specification of the ‘393 patent fails to sufficiently disclose the glass described in Claim 1.
Moreover, the specification of the ‘393 patent does not clearly describe which technical solution ensures that the glass obtained is not frangible, nor can a person skilled in the art deduce from the prior art or common knowledge that the glass produced using the technical solution in ‘393 patent is certainly not frangible. Furthermore, if ensuring that the produced glass is not frangible relies solely on conducting frangibility tests on each batch of glass products during actual production, it would obviously require excessive effort from a person skilled in the art to verify whether the products defined in the claims can be obtained based on the disclosures in the specification of the ‘393 patent.
Wisdom Suggested Strategies
In this case, the court overturned CNIPA’s opinion on whether the specification was sufficiently disclosed. The Beijing Intellectual Property Court took a more rigorous approach in examining the content disclosed in the specification, rather than hastily concluding that “a person skilled in the art should be able to understand”. In this case, the non-frangible property of the glass in the claims is defined by tensile stress being below the “frangibility limit”. Clearly, the non-frangible property in this case is a “parameter-limited” technical feature that limits the scope of Claim 1. If it is merely to describe that the invented item possesses a non-frangible property, a “non-limiting” approach could be used, such as including a descriptive statement regarding the properties in the preamble of the claims. When the non-frangible property is written as a technical feature in the claims, it is requireed that the specification provides sufficient disclosure of that technical feature. Although the specification in this patent refers to disclosures from other patent documents and omits the definition of the “frangibility limit”, as mentioned above, the embodiments in this case do not disclose the “frangibility limit” test for the glass, nor do they specify what the “frangibility limit” should be for the glass that possesses the technical feature described in condition (1). Accordingly, the court concluded that it is impossible to directly understand from the disclosures in the specification that the glass defined in the claims is necessarily non-frangible. A person skilled in the art would need to exert excessive additional effort to verify whether the invention in Claim 1 meets the technical feature of condition (2). Therefore, the specification’s disclosure was deemed insufficient.
Claims being supported by the specification is a fundamental requirement when drafting the specification. However, in drafting claims, the pursuit of broader claim scope often leads to overlooking this fundamental requirement. This judgment serves as a cautionary example for the drafting of both specifications and claims.
