Paragraph 2 of Article 22 of the Patent Act prescribes that “an invention that is without the circumstances prescribed in the subparagraphs of the preceding paragraph but can be easily made by a person ordinarily skilled in the art based on prior art shall not be patented.” According to the Patent Examination Guidelines[1], when determining the inventive step of a claimed invention, the auxiliary evidential document, which shows that the claimed invention produces an unexpected effect, solves a long-felt but unsolved problem, overcomes a technical prejudice or achieves commercial success, submitted by the applicant at the time of filing or during the prosecution to support the inventive step of the claimed invention should also be taken into consideration by the examiner. In addition, based on the Patent Examination Guidelines[2], the term “producing an unexpected effect” means that as compared with a relevant prior art, the claimed invention produces a technical effect which cannot be expected by a person having ordinary skill in the art at the time of filing, including a significant enhancement of an effect (i.e., a quantitative change) or a new performance (i.e., a qualitative change). In other words, even if a claimed invention produces a significant enhancement of an effect or a new performance, if such effect is expected for a person having ordinary skill in the art at the time of filing, the effect should not be considered unexpected.
 
Also, since the Patent Examination Guidelines[3] stipulates that “if a claimed invention has an unexpected effect as compared with the relevant prior art, it should be deemed as strong evidence in support of the existence of a factor affirming inventive step,” some applicants attempt to emphasize in the argument in response to an Office Action that the claimed invention has an unexpected effect as compared with the related prior art. However, such argument has often been regarded unpersuasive by examiners as being unsupported by evidence. Moreover, in patent litigation practice, it seems that a patentee may have difficulties in using “unexpected effects” as a factor for claiming the inventiveness of his/her patent, with the example from the 2020 Xing Zhuan Su Zi No. 60 judgment rendered by the Intellectual Property and Commercial Court (IPCC) on August 31, 2021. In the judgement[4], the IPCC held that
 
Unexpected effects include a new performance or a significant change in quantity. If a claimed invention has an unexpected effect as compared with relevant prior art that results from the technical features of the claimed invention, the unexpected effect is considered as evidence affirming that the claimed invention cannot be easily accomplished. The specification of the patent at issue or the evidence presented by the plaintiff only demonstrate that TDF or FTC is unstable at certain pH levels, and that the agents recited in the patent at issue have tolerable stability and reasonable processing suitability. However, these documents fail to demonstrate that a person having ordinary skill in the art would have considered that TDF and FTC are unable to to form a composition due to stability or degradation, let alone that a person having ordinary skill in the art would have recognized that the stability of the composition was unexpected. Moreover, as far as the new performance produced by the stability and other effects is concerned, the evidence item 2 has disclosed that TDF, FTC, and other ingredients can reduce the incidence of drug-resistance and have high compatibility, and relevant test procedures for compounding and manufacturing of tablets can be further carried out without important challenges. Hence, it cannot be determined that the performance produced by the aforesaid effects is new and unexpected by a person having ordinary skill in the art. As for the enhancement produced by the effects, the evidence submitted by the plaintiff did not sufficiently demonstrate the expected level of the enhancement to a person having ordinary skill in the art. Hence, based on the evidence, it is difficult to determine that the enhancement produced by the effects of the agents of the patent at issue indeed achieves a level better than expected by a person having ordinary skill in the art, not to mention that the enhancement has been significantly increased to an unexpected level. Based on the foregoing, it cannot be determined that the claimed inventions of the patent at issue produce unexpected effects as compared with the relevant prior art.
 
Consequently, the IPCC concluded that the patent at issue did not involve an inventive step.
 
However, in the 2022 Shang Zi No. 920 judgment rendered by the Supreme Administrative Court on February 29, 2024, the court affirmed the inventiveness of the patent at issue due to unexpected effects. The patent at issue provides a liquid crystal composition and a liquid crystal display element using the same. The liquid crystal composition does not deteriorate the dielectric anisotropy, viscosity, ceiling temperature of the nematic phase, nematic phase stability at low temperature and rotational viscosity γ₁, which are properties of the liquid crystal display element, and the residual image property of the display element; and hardly has the formation of dripping marks during the preparation thereof. In addition, in the ODF step the amount of the discharged liquid crystal material is stable and suitable for the liquid crystal display element. In the judgement[5], the Supreme Administrative Court held:
 
Paragraphs [0014] to [0015] of the specification of the patent at issue have specifically described that “in order to inhibit the formation of dripping marks, it is important to use specific compounds in specific mixing ratios, and in particular, it is clear that there are compositions that are difficult to produce dripping marks.” Also, by referring to the multiple embodiments/comparative examples having different compositions, it can be understood the effectiveness of the specific liquid crystal compositions in inhibiting the formation of dripping marks. Since the embodiments in the specification of the patent at issue have specifically described the multiple liquid crystal compositions capable of achieving the aforesaid effect of inhibiting the formation dripping marks, and it is not disputed by both parties that the inventions in the post-grant amendment to the claims of the patent at issue can be supported by the specification and can be enabled, it is reasonable to assume that a person having ordinary skill in the art can infer that the inventions in claims 1 to 7 of the patent at issue have achieved the aforesaid effects based on the technical features such as the specific liquid crystal compositions as defined therein. Hence, such effects may be taken into account as a favorable factor in determining the inventiveness of the inventions.
 
As a result, the Supreme Administrative Court concluded that the patent at issue involved an inventive step. In view of this judgment, the specific description of certain effects in the specification of the patent at issue and the evaluation of the particular effects achieved by the invention through embodiments and/or comparative examples may be particularly helpful in the case the patentee asserted that the invention produced unexpected effects.
 
Based on the foregoing, the assertion of the applicant/patentee regarding “unexpected effects” requires the applicant/patentee to present factual and objective evidence, including test results and a description explaining why the claimed invention achieves an unexpected effect relative to the prior art, both of which are necessary. That is, a showing of unexpected effects must be based on evidence, not argument or speculation. Moreover, the Supreme Administrative Court also rendered a judgment[6] opining that when deciding an inventive step of a claimed invention, the patentee’s evidence and arguments regarding auxiliary factors are required to be taken into consideration by the subordinate courts; otherwise, the decisions will be unlawful. Therefore, the aforementioned judgments rendered by the Supreme Administrative Court not only indicate that the auxiliary factors should be taken into consideration when determining an inventive step of a patent, but further elaborate that “unexpected effects” asserted by the patentee does affect the determination of inventiveness. Accordingly, an applicant or a patentee may cite the opinions of these Supreme Administrative Court judgments in the prosecution of a patent application or during the invalidation proceedings to proactively defend an inventive step for a patent.