One Case a Day | China: Method for Negating Reverse Teaching – "Ultra-Thin Food Container" Case, Invalidation Decision No. 563911 (2023)

Case Introduction

Hello to all the friends who persist in reading. Today, we share a case related to reverse teaching ("teaching away").

In the judgment of inventiveness, the presence or absence of technical teaching or guidance often serves as the decisive factor that shifts from "could" to "would." If there is clear reverse teaching that prevents a person skilled in the art from making a combination, it is undoubtedly very favorable for the patentee or applicant, but not so friendly for the invalidation requester.

To be fair, any technical solution is inevitably a combination of multiple advantages and disadvantages. When technicians seek inspiration, they do not abandon the advantages of a technical solution simply because it has disadvantages; instead, they make judgments based on actual circumstances. This case provides a general method for negating reverse teaching from the perspective of the independence of technical features and their relevance to technical problems, which is of guiding significance.

Additionally, the inventive point of the claims in this case involves numerical parameters. In the invalidation proceedings, the collegial panel directly characterized it as a conventional technical means in the absence of evidence, which is also noteworthy.

Case Information

• Application Number: 201010265807.X
• Invention Title: A Fully Sealed Ultra-Thin Food Container
• Invalidation Request Information: 4W116180
• Invalidation Decision Information: No. 563911
• Decision Date: October 24, 2023

Key Points of the Decision

In the judgment of inventiveness, it cannot be concluded that there is reverse technical teaching in the prior art merely because the emphasis of the invention recorded in the prior art is different. It is further necessary to consider whether this emphasis is related to the actual technical problem solved by the distinguishing technical features and the determination of technical teaching.

... If the relevant features disclosed in the prior art are not closely related to other features and independently perform the same function as the distinguishing features, then a person skilled in the art can filter out information unrelated to the actual technical problem to be solved, and has the motivation to separate the relevant features from the overall technical solution of the prior art and combine them with the closest prior art, thereby determining from the overall technical solution of the prior art whether there is corresponding technical teaching or reverse technical teaching.

Case Summary

The relevant patent Claim 1 protects a fully sealed ultra-thin food container.

The edge of the lid forms an annular groove [11] composed of an inner groove wall [111], a groove top [112], and an outer groove wall [113].

The mouth of the container body forms a container mouth double edge [21] composed of an inner straight edge [211], a flat edge [212], and an outer straight edge [213].

The groove [11] is sleeved and buckled on the container mouth double edge [21]; the protrusion [114] on the inner side of the outer groove wall [113] locks the lower end of the outer straight edge [213]. The innovation lies in:

The inner straight edge [211] or the inner groove wall of the groove [11] is vertical, and the inner groove wall [111] and the inner straight edge [211] are pressed together, with an angle of 1°–12° between them.

Through the above arrangement, the pressed contact between the inner groove wall [111] and the inner straight edge [211] forms a sealing line, which is the inner sealing structure of the present invention. Compared with the prior art, since the sealing line of the inner sealing structure in the present invention is the intersection line of two smooth curved surfaces, on the one hand, when the container is subjected to significant deformation under pressure, this sealing line also deforms along with the two smooth curved surfaces but always maintains a closed-loop state, i.e., the line sealing is not destroyed, and the inner sealing structure is relatively stable; on the other hand, there is only pressed contact between the two smooth curved surfaces, without interlocking convex rings, making it easier to open the lid.

Controversial Focus

Evidence 1 (CN100456989C) is a prior application of the patentee and also discloses a fully sealed ultra-thin food container, which achieves sealing through the interlocking of two convex rings [14, 24].

Evidence 3 (JP1997226797A) discloses a food packaging container. The fitting groove [32] of the container body [21] has an outwardly widened inclined groove side surface [38], and the fitting groove [42] of the lid [22] has a vertical groove side surface [48]. The contact line between the inner side surface of the fitting groove [32] and the outer side surface of the fitting groove [42] is mutually pressed to form the first and second sealing parts [51] and [52]. Since near the opening of these sealing parts [51] and [52], the fitting grooves [32] and [42] are in line contact and mutually pressed, the sealing ability can be improved.

The patentee argued: The fitting groove in Evidence 3 opens upward, excluding the technical solution of the groove opening downward in this patent, thus providing reverse technical teaching.

Therefore, the controversial focus of this case is: Does the opposite opening direction of the fitting groove in Evidence 3 constitute reverse teaching?

Invalidation Decision

1. In the judgment of inventiveness, it cannot be concluded that there is reverse technical teaching in the prior art merely because the emphasis of the invention recorded in the prior art is different. It is further necessary to consider whether this emphasis is related to the actual technical problem solved by the distinguishing technical features and the determination of technical teaching. When a person skilled in the art judges whether the prior art discloses the distinguishing features and solves the same technical problem, providing technical teaching, they need to analyze, select, and judge the content disclosed in the prior art, consider the role of the corresponding technical features disclosed in the prior art in its overall technical solution. If the relevant features disclosed in the prior art are not closely related to other features and independently perform the same function as the distinguishing features, then a person skilled in the art can filter out information unrelated to the actual technical problem to be solved, and has the motivation to separate the relevant features from the overall technical solution of the prior art and combine them with the closest prior art, thereby determining from the overall technical solution of the prior art whether there is corresponding technical teaching or reverse technical teaching.

2. Evidence 3 addresses the technical problems of liquid leakage during sealing and difficulty in opening the lid of food containers, setting the fitting groove opening upward and forming line sealing on both sides of the groove;

Evidence 1 addresses the technical problem of food containers being prone to leakage, setting interlocking convex rings on the lid and container body for sealing;

This patent addresses the technical problems of unstable sealing and difficulty in opening the lid of the convex ring sealing in Evidence 1, adopting the technical means of surface-to-surface line contact sealing structure.

Evidence 3 and Evidence 1 are technical solutions proposed for different technical problems faced by food containers. However, the different emphasis of the inventions does not lead to reverse technical teaching for solving the above technical problems of this patent.

3. First, regarding the sealing structure, the closest prior art is Evidence 1. A person skilled in the art improves based on Evidence 1. The overall structure of this patent is basically the same as that of Evidence 1, with the only difference being the line sealing structure. Evidence 3 discloses a technical solution using surface-to-surface line contact sealing to reduce friction resistance, solving the technical problem of difficulty in opening the lid. The surface-to-surface line contact sealing is not closely related to other features and independently performs the same function as the distinguishing features. A person skilled in the art, under the technical teaching of Evidence 3, has the motivation to replace the convex ring interlocking sealing structure in Evidence 1 with the surface-to-surface line contact sealing structure, rather than focusing only on the difficulty of sealing on both sides of the fitting groove in Evidence 3, which cannot achieve sealing on one side.

4. Second, the technical problem solved by Claim 1 of this patent relative to Evidence 1 is "providing another inner sealing structure that ensures sealing stability while making lid opening easier." A person skilled in the art, starting from Evidence 1, needs to find prior art that can solve the above technical problem.

The disclosure of "the fitting groove opening upward" in Evidence 3 is to solve the problem of liquid leakage when the opening faces downward during sealing, while "forming line sealing on both sides of the groove" is not related to the problem to be solved by the prior art being sought. A person skilled in the art can filter out information unrelated to the technical problem to be solved and has the motivation to separate the surface-to-surface line contact sealing from the overall technical solution of Evidence 3 and combine it with Evidence 1.

5. It can be seen that although Evidence 1 and Evidence 3 have different emphases, they are essentially sealing structures for containers and are not contradictory. A person skilled in the art can choose specific sealing structures according to actual needs. Evidence 3 and Evidence 1 do not constitute reverse technical teaching, and there is no obstacle to combination. On this basis, setting the angle between the inner groove wall of the groove and the inner straight edge of the container mouth double edge to 1°–12° is a conventional technical means in the field, and the technical effects produced are also reasonably predictable by a person skilled in the art. In summary, the patentee's arguments are not persuasive, and the collegial panel does not support them.

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Feng Shangjie (Gasoll Feng)