[Key Points of the Judgment]

An open-ended claim does not, in form, exclude a particular element, so particular caution must be exercised in determining whether it constitutes an element-omission invention. The determination should be made from the standpoint of a person skilled in the art, starting from the technical solution of the invention as a whole, and taking into account the object of the invention, the contents of the claims and the description, the function in the prior art of the element that the party alleges to have been omitted, and other relevant factors. Where the element alleged by the party to have been omitted has a particular function in the reference document, and the claimed invention, after omitting that element, cannot achieve that particular function and does not bring about any unexpected technical effect, it will generally not be found to constitute an element-omission invention.

[Keywords]

Administrative; invalidation of an invention patent right; novelty; inventive step; element-omission invention; open-ended claim

[Basic Facts of the Case]

A certain U.S. company is the patentee of the invention patent numbered 20131024****.6 and entitled "Improved pressure sensor for detecting operating parameters of a household appliance characterised by a relatively movable component" (hereinafter "the patent at issue"). Claim 1 of the patent at issue reads: "1. A pressure sensor (100), the pressure sensor (100) comprising a rigid housing (10), the housing (10) accommodating a deformable membrane (11) sensitive to hydraulic pressure, characterised in that the pressure sensor comprises:

a first counter spring (25) and a second counter spring (35);

the housing (10) being divided by the membrane (11) integrally and in a liquid-tight manner into a first chamber (15) and a second chamber (12);

the first chamber (15) accommodating the first counter spring (25);

the second chamber (12) accommodating the second counter spring (35);

a magnetic core (200), the magnetic core being made of a ferromagnetic material and being operatively associated with the membrane (11) so that, in response to deformation of the membrane (11), the magnetic core (200) moves within the housing (10);

a coil (21), the coil being fixed to the housing and being operatively coupled to the magnetic core (200) so as to form a variable inductive sensor (22);

wherein one end of the first counter spring (25) abuts against a threaded cap (50c)."

On 5 August 2020, Cheng filed a request for invalidation against the patent right at issue, the principal ground being that claim 1 of the patent at issue lacked novelty, and submitted the following principal evidence: Evidence 1, German patent document DE197458****; Evidence 2, French patent document FR27147****; Evidence 3, French patent document FR27671****.

On 18 January 2021, the China National Intellectual Property Administration issued Invalidation Examination Decision No. 47785 (hereinafter "the accused decision"), holding that the technical solution actually claimed in claim 1 of the patent at issue was a technical solution achieving calibration by means of a first counter spring and a second counter spring, whereas the pressure sensors in the reference documents each comprised two helical springs together with one leaf spring. The prior art did not disclose a technical solution in which the leaf spring could be omitted and only two helical springs used. Accordingly, claim 1 of the patent at issue possessed novelty, and the patent right at issue was maintained as valid. Dissatisfied, Cheng brought an action before the Beijing Intellectual Property Court, requesting that the accused decision be revoked and that the China National Intellectual Property Administration be ordered to make a new decision.

On 21 March 2022, the court of first instance rendered an administrative judgment revoking the accused decision and requiring the China National Intellectual Property Administration to make a new examination decision. Dissatisfied, the U.S. company appealed. On 2 August 2024, the Supreme People's Court rendered administrative judgment (2022) Zui Gao Fa Zhi Xing Zhong No. 476, dismissing the appeal and upholding the original judgment.

[Opinion of the Court]

The effective judgment of the court held: an element-omission invention refers to an invention in which one or more elements of a known product or process are omitted without losing the corresponding function of that element, or which is capable of bringing about an unexpected technical effect. Where the claimed invention is drafted in the form of an open-ended claim, since a particular element is not excluded in form, particular caution must be exercised in finding that it constitutes an element-omission invention. In determining whether a claimed invention constitutes an element-omission invention, the determination should be made from the standpoint of a person skilled in the art, starting from the technical solution of the invention as a whole, and taking into account the object of the invention, the contents of the claims and the description, the function in the prior art of the element that the party alleges to have been omitted, and other relevant factors. If the so-called omitted element has a particular function in the reference document, and the claimed invention, after omitting that element, cannot achieve that particular function and does not bring about any unexpected technical effect, that is generally insufficient to support a finding that it constitutes an element-omission invention.

In this case, claim 1 of the patent at issue was drafted in the form of an open-ended claim. An open-ended claim generally does not exclude structural components or process steps not recited in that claim. The word "comprising" in claim 1 of the patent at issue itself indicates that unrecited content is not excluded, and it should be construed as permitting the further inclusion of structural components not recited in the claim. In such a case, determining whether it constitutes an element-omission invention requires all the more that the record of the description be taken into account and that a comprehensive determination be made from the technical solution of the patent at issue as a whole in combination with the object of the invention.

First, from the entirety of the record in the description of the patent at issue concerning the defects of the background art and the object of the invention of the patent at issue, there is nothing indicating that the patent at issue implicitly limited itself by omitting the "leaf spring." As is apparent from the description of the patent at issue, the object of the invention of the patent at issue is to provide an improved pressure sensor which is not limited to being mounted on a movable component of a household appliance, so that the dimensions of the pressure sensor are no longer restricted by the mounting position and the difficulty of installation is reduced. Viewed from the technical solution as a whole, whether the patent at issue can achieve the above object of the invention has no connection with the "leaf spring." Moreover, the description of the patent at issue never mentions the "leaf spring," and a person skilled in the art, when reading the claims and description of the patent at issue and proceeding from the technical solution as a whole, likewise cannot directly and unambiguously determine that claim 1 of the patent at issue excludes the "leaf spring."

Second, viewed from the function in the prior art of the allegedly omitted element as asserted by the U.S. company, the patent at issue, by not adopting the "leaf spring," would correspondingly also lose the function possessed by the "leaf spring." The reason the pressure sensors in the reference documents adopt the "leaf spring" is to achieve more efficient calibration; the "leaf spring" is not a necessary condition for the normal operation of a pressure sensor, and where efficient calibration is no longer the focus of attention, the reference documents may omit the "leaf spring." Likewise, if the patent at issue does not adopt the "leaf spring," it correspondingly also loses the above function possessed by the "leaf spring." Moreover, one end of the helical spring in the reference documents also abuts against an adjusting member (corresponding to the threaded cap of the patent at issue), and the recitation in claim 1 of the patent at issue that "one end of the first counter spring abuts against a threaded cap (50c)" cannot exclude the possibility that the patent at issue provides a "leaf spring" and adjusts it.

In sum, the assertion of the U.S. company that claim 1 of the patent at issue is an element-omission invention and that the omission of the "leaf spring" constitutes a distinguishing feature between the patent at issue and the reference documents cannot be sustained. Since the accused decision erred in its finding on the distinguishing features between claim 1 of the patent at issue and Evidence 1 to 3, the question of whether the patent at issue possesses novelty and an inventive step should be re-examined on the basis of correcting the above finding.

[Related Index]

Article 22, paragraph 2 of the Patent Law of the People's Republic of China (the version applicable in this case is Article 22, paragraph 2 of the Patent Law of the People's Republic of China which came into force on 1 July 2001)

Source: Intellectual Property Court of the Supreme People's Court, 7 August 2026. Original: https://ipc.court.gov.cn/zh-cn/news/view-5994.html