During an assessment of inventiveness, when ascertaining whether a distinguishing technical feature of a patent claim has an identical effect to that of a corresponding technical feature disclosed in the prior art, it is necessary to examine the effect that the corresponding technical feature achieves within the entire context of the prior art, rather than merely rely on common knowledge to understand the effect without considering its specific relationship with other features of the prior art.
Under Article 22 of the Patent Law, in order to be patented, an invention must involve an inventive step over the prior art. The invention must exhibit prominent substantive features and represent notable progress. For determining such an inventive step, the Guidelines for Patent Examination set out the following three-step method:
- determine the closest prior art;
- determine the invention's distinguishing technical features and the technical problem to be addressed by the invention;
- determine whether there is such technical teaching as to motivate a person skilled in the art to apply the distinguishing technical features to address the technical problem in the closest prior art.
The Guidelines for Patent Examination sets out three scenarios in which prior art is generally perceived to contain technical teaching:
- The distinguishing technical features are common knowledge.
- The distinguishing technical features are the technical means disclosed in the other parts of the closest prior art and the effect that such technical means achieves in other parts thereof is identical with that which the distinguishing technical features achieve in the claimed invention in order to resolve the technical problem.
- The distinguishing technical features are the technical means disclosed in another prior art and the effect that such technical means achieves in such other prior art is the same as that which the distinguishing technical features achieve in the claimed invention in order to resolve the technical problem.
In patent invalidation proceedings, especially in the machinery field, a global view of the prior art is necessary when assessing the effect of a technical feature in deriving technical teaching of the prior art. This is because there is often a high level of synergy between multiple technical features in prior art. Where a party fails to achieve a global view, they run the risk of erring in their determination of inventiveness.
In a recent case, the owner of a Chinese patent for a culinary utensil invention sued an infringer, which retaliated by filing an invalidation request against the patent.
The patent in question concerned a cooking utensil comprising a food container and a blade, which were both relatively rotational. The core invention was that the blade comprised a turnover device, which caused the food to turnover in a specific direction under the action of the relatively rotational movement (ie, mainly along a radial direction).
Figure 1: perspective view of cooking utensil of subject patent
Figure 2: front view of blade of subject patent
The subject patent description and the accompanying drawings embodied Claim 1. As shown in Figures 1 and 2 above, a blade (8) in Container 2 included a turnover device (13, the blue portion in Figure 1), which was displaced in the rotational direction relative to a front reflecting plate (16, the red portion in the above image). A groove (200) for food passage was provided between the turnover device (13) and the front deflecting plate (16). The illustrated turnover device was a bevel that inclined rearward and gradually narrowed in the direction (17) in which the blade rotated relative to the container. In use, the front deflecting plate blocked food and pushed it towards the turnover device. The food was moved over the turnover device, and the inclined bevel configuration allowed it to be turned over towards the centre of the container in a controlled manner (ie, mainly in a radial direction (D)). The turnover of food was controlled in this particular direction, which enabled the device to effectively stir food and achieve good technical effects (eg, uniform heating).
The closest prior art cited by the defendant belonged to the same technical field as the subject patent. As shown in the images below (Figures 3 and 4), it disclosed the container (8) and the blade (16) disposed therein, both of which were relatively rotatable. The blade was disposed transversely in the container and was V-shaped as a whole, so that the blade had a V-shaped groove (16C) and the first and second portions on both sides thereof (the red portions in the below figures). The first and second portions were respectively adjacent to the outer lateral wall (8B) of the container and the container centre axis (X-X). In use, the first and second portions of the blade were used to block the food, allowing it to pass through the V-shaped groove, thereby achieving the turnover and stirring of the food. Due to the transversal arrangement of the V-shaped groove, the food was apparently not turned in a mainly radial direction.
Figure 3: cross-sectional view of cooking utensil covered by closest prior art
Figure 4: top view of blade covered by closest prior art
In the invalidation procedure and the subsequent administrative litigation proceedings, the dispute focused on:
- whether the technical solution of Claim 1 of the disputed patent was obvious compared with the closest prior art and common knowledge; and
- more specifically, whether the effect of the first portion of the blade of the closest prior art was identical with that of the turnover device of Claim 1.
One of the defendant's arguments in the invalidation procedure was that the general structure of the first portion of the blade was similar to the turnover device of the subject patent (ie, a bevel inclined rearward and gradually narrowed in the direction in which the blade rotated relative to the container). Therefore, the first portion of the blade of the closest prior art in combination with common knowledge achieved the same effect as the turnover device of Claim 1 of the disputed patent. Based on this finding, the technical solution of Claim 1 was found to be obvious compared with the closest prior art, which meant that there was no inventive step. The Patent Re-examination Board and the first-instance court therefore sided with the defendant and upheld the invalidation request.
In order to rebut the aforesaid argument, the plaintiff conducted research on the written description and drawings of the disputed patent and the closest prior art. Based on this research, the plaintiff drew a schematic diagram, comparison drawings and physical models, which demonstrated that when considering the closest prior art as a whole, the first and second portions of the blade worked in concert to block the food and allow it to pass through the transversally disposed V-shaped groove, rather than allowing the food to be primarily turned in a radial direction. It was therefore established that when taking into account the closest prior art as a whole, even though the first portions of the blades were somewhat similar, due to their different effects in the claimed invention and the prior art, a person skilled in the art was unlikely to obtain the technical teaching to combine the closest prior art with common knowledge to arrive at Claim 1 of the disputed patent. Thus, Claim 1 was non-obvious and involved an inventive step. The court of appeal agreed with this argument and dismissed the invalidation request.
This case may serve as a point of reference for assessing technical teaching. In practice – particularly in cases involving machinery – even though a structure extracted from prior art is identical or similar to a technical feature of a patent claim, a technical teaching could be erroneously derived if the structure's effect is considered based only on the extracted structure alone and not the effect that the structure achieves within the whole context of the invention.
Therefore, it is advisable to analyse not only whether prior art literally or graphically discloses the technical features of a claim, but also whether the corresponding features within the whole context of the prior art achieve the same effect as the claimed technical features in resolving the technical problems addressed by the claims.
This article was first published by the International Law Office, a premium online legal update service for major companies and law firms worldwide. Register for a free subscription.