When assessing whether an invention is eligible for patent protection, inventiveness constitutes one of the core criteria of assessment, as it directly relates to the recognition of technological innovation value and the promotion of scientific and technological progress. Under the Chinese Patent Law, an invention is considered to involve an inventive step if, as compared with the prior art, it possesses prominent substantive features and represents notable progress. Within the analytical framework for examining inventiveness, the “technical problem actually solved by the invention” serves as a critical bridge connecting the closest prior art and the obviousness determination. Accordingly, the identification of the technical problem may function as a benchmark for assessing inventiveness and exert a decisive influence on the final examination conclusion.
1. Rules for determining technical problems in Patent Examination Guidelines
The Patent Examination Guidelines specify that: the technical problem actually solved by an invention refers to the technical task that requires improvement to the closest prior art in order to achieve better technical effects. The Patent Examination Guidelines revised in December 2023 further refined the rules for determining this technical problem, emphasizing two core points:
(1) The newly determined technical problem must match the technical effects achieved by the distinguishing features in the invention, and must not be directly equivalent to the distinguishing features themselves, nor should it contain guidance or implications for the distinguishing features;
(2) Special circumstances have been added. If all the technical effects of the invention are equivalent to those of the closest prior art, the technical problem actually solved should be defined as "providing an alternative technical solution different from the closest prior art." It should be clarified that under this special circumstance, inventiveness cannot be directly concluded. It is still necessary to further determine whether this alternative solution would have been obvious to those skilled in the art.
2. Practical application of determining rules for technical problems from a case study
The judgment on the patent invalidation case of compound fertilizer high-tower granulation in the Summary of Judicial Essentials (2024) issued by the Intellectual Property Tribunal of the Supreme Court corrected errors in the determination of the technical problem during the patent validity proceedings, demonstrated the judgment rules applicable in special circumstances, and vividly illustrates the practical application of these rules.
In this case, Claim 1 of the granted patent protects a "method for producing granular compound fertilizer using a high-tower granulation process", with the core distinguishing technical feature being "the granulation tower is 80-125m high". Evidence 1 submitted by the invalidation petitioner (a prior patent from the same applicant) discloses the "method for producing compound fertilizer using low-tower granulation process", with a tower height of 15-45m. In the invalidation decision, the China National Intellectual Property Administration (CNIPA) directly defined the technical problem as "how to achieve granular compound fertilizer production using a high-tower granulation process". The definition directly encompassed the distinguishing technical feature of "high tower" and consequently maintained the patent’s validity on the grounds that the prior art did not disclose granulation towers over 80 meters for compound fertilizer production.
In the first instance, the Beijing Intellectual Property Court rectified this error, clarifying that the actual technical problem solved by an invention should be determined based on the role played by the distinguishing technical features in the technical solution of the invention and the technical effects achieved, rather than the distinguishing features themselves. When assessing the technical effects achieved by distinguishing technical features of the invention compared to Evidence 1, the court found that the core performance parameters of the product obtained from the patent were highly consistent with those of Evidence 1, and that no substantive difference in technical effects was demonstrated. Therefore, the actual technical problem solved by the patent was redefined as "providing an alternative technical solution for producing granular compound fertilizer". Based on this redefined technical problem, and in view of the common technical knowledge in the prior art regarding the correlation between granulation tower height and cooling effects, the court concluded that this technical solution would have been obvious to those skilled in the art.
The patentee appealed to the Supreme Court against the judgment of the Beijing Intellectual Property Court. In the second instance, the Supreme Court upheld the judgment of the court of first instance, endorsing the trial logic of the lower court, and reaffirming the core rules for determining technical problems.
3. The "three-step method" logic for determining technical problems
Based on the provisions of the examination guidelines and typical case practices, the determination of the actual technical problem solved by an invention should follow the "three-step method" logic:
The first step is to "identify the technical effects brought by the distinguishing technical features", which should focus on quantifiable indicators such as product performance parameters, production efficiency, and energy consumption levels. Experimental data should be prioritized to prove an objective basis for determining technical problems;
The second step is "assessing the effect differences". Compare the invention with the closest prior art to determine whether any differential effect arises. If a differential effect exists, the subsequent determination of technical problem should focus on the improvement corresponding to this technical effect; if no substantial difference arises, the technical problem should be defined as "providing an alternative technical solution";
The third step is "determining technical problems", which involves objectively describing the existing technical defects or the improvement directions that the invention seeks to address, based on the assessment of effect differences.
Throughout the "three-step method" process, it is crucial to adhere to the core principle of "separating the technical problem from the distinguishing features themselves".
4. Conclusion
The rational definition of technical problems can be regarded as the logical starting point for the examination of inventiveness. It not only determines the direction of the obviousness assessment but also directly affects the fairness of the inventiveness evaluation. Only by strictly adhering to the rules of "effect matching, separation from the distinguishing features, and objective neutrality" can we avoid hindsight-based misjudgments, accurately identify truly innovative technical solutions, safeguard the legitimate rights and interests of patentees, and uphold the legislative purpose of the patent system to encourage innovation and promote technological progress.
