Sanyou Client: Sensirion AG
Trial Organ: Supreme People's Court
Trial Result: Revocation of the invalid decision

Case facts
Roger Unger, owner of the invention patent "compact and low-cost particle sensor", filed an infringement lawsuit against the products of Suzhou Beiang Technology Co., Ltd. (hereinafter referred to as Suzhou Beiang). In the process of Suzhou Beiang's request for the patent invalidation, Roger Unger's attorney made an incorrect definition on the scope of the claim. CNIPA declared that the patent right remained valid based on the incorrect definition of the claim. At this point, although the patent has been maintained valid, the scope of protection is completely incorrect and cannot be implemented. After that, Roger Unger transferred the patent right to Sensirion AG.

Entrusted with Sensirion’s administrative litigation of this case, Sanyou successfully revoked the invalidation decision made due to incorrect definition of the scope of the claims, thereby retaining the opportunity for subsequent exercise of patent rights.

Hearing process
On September 5, 2017, Suzhou Beiang filed a request for invalidation against Sensirion’s patent. During the trial, Roger Unger's attorney argued that the "beam" in claim 1 is a parallel laser. Based on this, CNIPA made the invalidation decision No. 35722, maintaining the validity of the patent right.

In October 2018, Roger Unger filed an administrative lawsuit with Beijing Intellectual Property Court (Beijing IP Court) and transferred the patent right to Sensirion AG. Sensirion then transferred the case to Sanyou.

Sanyou attorneys confirmed that "a beam of light" is not a parallel light by reviewing materials, collecting evidence, and requesting experts in the field to provide testimony. On October 20, 2020, Beijing IP Court issued an administrative judgment (2018) J73 Xingchu No. 11078, revoking the invalidation decision No. 35722.

Suzhou Beiang appealed to the Supreme People's Court against the first instance judgment. In September 2022, the Supreme People's Court issued judgment No. 338 (2021), upholding the first instance judgment.

Focus of disputes
There are two disputes in this case.
1. Whether the "beam of light" in the claims is objectively "parallel light".
2. The patentee claimed that the scope of protection was "parallel light" during the invalidation process, and therefore maintained the patent right. In the subsequent litigation, the patentee claimed that the scope of protection was not "parallel light". Whether it violates the principle of estoppel?

Dispute 1
In the specification, the embodiment of a beam is "collimation/focusing laser". For many, laser is a parallel light, which is why in the invalidation procedure, the collegial panel recognized the patent holder's statement of "parallel light".

However, this is not the case with objective facts. In the first instance proceedings, Sanyou attorneys collected multiple textbooks and other materials from relevant fields, and managed to obtain testimony from technical experts in this field, proving that the laser is not a parallel beam. The so-called "collimated/focused laser" actually refers to the different states of the same laser beam, rather than different laser beams. Therefore, the statement of "parallel light" does not conform to objective facts, and there is an error in factual determination in invalidation decision No. 35722.

Dispute 2
The principle of estoppel refers to the principle that if the patentee defines the scope of the claims (such as restrictive amendments or interpretations) in order to meet the statutory granting requirements during the patent approval process (including the examination process of the patent application or the invalidation, objection, and retrial procedures after patent grant), the content abandoned through such definitions shall not be included in the protection scope of the patent when claiming the patent right.

First, as the literal meaning suggests, the principle of estoppel is a constraint on the exercise process by the observation made during the right confirmation process, rather than a constraint on the subsequent confirmation process by the previous confirmation process. As pointed out in the second instance judgment, in the patent grant and confirmation process, the observations of the patentee should be considered as to whether it falls within the scope of reasonable explanation by technical personnel in this field. The reasonable interpretation of the claims shall not be affected by whether the observation of the patentee has changed or not.

Second, in this case, the embodiment in the specification is "collimation/focusing laser". As mentioned earlier, "collimation/focusing laser" does not mean "collimation laser or focusing laser can be used", but rather "collimation or focusing state of laser beam can be used". Therefore, even if "collimation" is considered as "parallel", interpreting "a beam of light" in the claims as "a beam of parallel light" is not a narrowing definition on the scope of the claims, but rather a completely different protection scope from the original protection scope established by the new definition. From this perspective, it also does not comply with narrowing the scope of claims through definition as provided in the principle of estoppel.

Therefore, the principle of estoppel is not applicable in this case.

Typical significance
In the patent application and invalidation process, if a patentee claims an explanation that contradicts objective facts in order to obtain grant, even if the patent is granted or remains valid based on the explanation that contradicts objective facts, in subsequent procedures, the patentee can still overturn the aforementioned opinion that does not comply with objective facts based on the specification, and explain the technical solutions recorded in the specification based on objective facts.