A case in which the wording of “substantially polygonal shape” in the matters specifying the invention was found to be unclear to an extent that would unjustly harm the interest of a third party

1. Introduction

This newsletter introduces a case (No.2022 (Gyo-Ke) 10019, hereinafter, referred to as “Case”), in which a trial decision of dismissal of a request for a trial for patent invalidation was rescinded, because the wording of “substantially polygonal shape” in the matters specifying the invention was unclear to an extent that would unjustly harm the interest of a third party. The point at issue in the Case was whether the wording of “substantially polygonal shape” was unclear, and a certain standard of judgement was presented. Specifically, in the Case, it was found that there is a boundary defining a technical scope between the wording of “polygonal shape (without ‘substantially’)” and “substantially polygonal shape”. Consequently, the wording of “substantially polygonal shape” was found to be unclear.

2. Outline of the CaseIntroduction

The Case is a lawsuit to seek rescission of a decision (hereinafter, referred to as “Decision”) to the effect that a request for a trial for invalidation (Invalidation Trial No. 2020-800043) against a patent (Patent No. 6031654, hereinafter, referred to as “Patent”) is groundless. The court rescinded the Decision because the Decision erroneously concluded that the wording of “substantially polygonal shape” according to each of the invention (hereinafter, referred to as “Invention”) of the Patent was clear.

3. Constituent Features of the Patent

The invention of claim 1 of the Patent is shown below with signs (A) to (D). Hereinafter, a description of “matter (A) specifying the invention” or the like is used in accordance with the signs (A) to (D).

[Claim 1]

A drawing machine comprising:

(A) a die holder that holds a drawing die having a substantially cylindrical shape and causes the drawing die to rotate around a central axis of the substantially cylindrical shape of the drawing die; and

(B) a box storing a lubricant that is applied to a wire material so that the wire material is pulled into the drawing die,

(C) wherein an opening of a bearing portion of the drawing die has a cross-sectional shape that is a substantially polygonal shape and

(D) wherein the cross-sectional shape of the opening is the same along a direction in which the wire material is drawn.

4. Point at Issue

<1>. The main point at issue in the Case are as follows.

With regard to “(2) Reasons for Invalidation 2-3 (Violation of Clarity Requirements)”

In particular, it was disputed whether the wording of “substantially polygonal shape” in the matter (C) specifying the invention, “an opening of a bearing portion of the drawing die has a cross-sectional shape that is a substantially polygonal shape“, is unclear.

<2>. The Decision concluded that the wording was clear, on the grounds that the “substantially polygonal shape” means a shape having a radius of an arc in a corner to the extent that the lubricant is less likely to accumulate in one place. The following is an excerpt from the Decision.

The curvature of about “0.8 mm in radius” is an example of a numerical value of the radius of curvature of the roundness, which is given for the purpose of helping to understand the above tentative interpretation, and is not necessarily interpreted as limiting the “substantially polygonal shape”. Paragraph [0055] of the specification discloses that the lubricant is less likely to accumulate in one place if the opening of the die has an arc with a curvature of about 0.8 mm in radius. If the radius of the arc is larger than 0.8 mm, the cross-section of the opening of the die will be closer to a circular cross-section, and thus, it is natural that the lubricant is less likely to accumulate in one place.

Therefore, the plaintiff’s argument cannot be adopted.

<3>. In response to the Decision, the plaintiff argued that it is wrong to focus only on the value of the radius because a radius of an arc recognized as the substantially polygonal shape is different depending on the size of the polygonal shape itself, and it is impossible to determine what shape belongs to the “substantially polygonal shape”. The following is an excerpt of the plaintiff’s argument.

<Plaintiff’s Argument (Reasons for Rescission of Trial Decision)>

The technical significance of the Inventions is that the cross-sectional shape of the opening of the bearing portion of the die has the “substantially polygonal shape” so that there is no corner where the lubricant accumulates. From this point of view, it is wrong to focus only on the value of the radius, and it is necessary to consider the value of the radius of curvature in relation to the length of one side. In the example described in paragraph [0055] of the specification, the arc with the radius of curvature of 0.8 mm is shown at the corner of a square cross-section with one side being 4 mm in the opening of the bearing part. If the side length thereof is 1.5 mm, an arc with a radius of curvature of 0.3 mm is analogous to the example.

Thus, when viewed objectively, a person skilled in the art is unable to distinguish between a shape in which arcs created by normal machining i.e. wire discharge are in the corners of the opening, and the “substantially polygonal shape”. It is also unable to determine what shape belongs to the “substantially polygonal shape.” Therefore, the wording of “substantially polygonal shape” in the matter (C) specifying the invention is unclear to an extent that would cause unexpected disadvantage to a third party.

<4>. The defendant made a counterargument to the plaintiff’s argument, which is generally the same as the Decision. The following is an excerpt from the defendant’s argument.

<Defendant’s Argument>

A person skilled in the art can easily understand that an active processing to round the corners means to increase the radius of curvature compared to the roundness that are inevitably created in the corners by wire discharge, and thus, the person skilled in the art can easily understand that there is a difference between them.

The Decision did not extract or read only a specific numerical value as a requirement for the Invention, but used it as an example in the interpretation of the “substantially polygonal shape” to explain a state in which a “base polygonal cross-section” is actively processed to round off the corners where the lubricant accumulates, based on the description in paragraph [0055] of the specification. Therefore, the plaintiff’s argument is unreasonable.

5. Court’s Judgment

With regard to the above-described point at issue, the court judged that the wording was unclear because the boundary (distinction) between the “base polygonal cross-section,” which is not included in the technical scope of the patented invention, and the “substantially polygonal shape,” which is included in the technical scope of the patented invention, was unclear. The following is an excerpt from the judgment

The term “substantially polygonal shape” is literally understood to mean a shape that is generally polygonal in shape. However, it is unclear from the literal meaning of the wording what specific shape corresponds to the “substantially polygonal shape”.

The “substantially polygonal shape” in the Invention is tentatively interpreted to mean a shape created by rounding off all or part of the corners of the “base polygonal cross-section”. Therefore, based on their meanings, they should be clearly distinguished from each other.

However, according to the evidence (A 31, 32, 36, 37) and the entire import of oral arguments, it is found that if a hollowing processing is performed by wire discharge to form an opening having a polygonal cross-sectional shape, the corners of the opening inevitably become rounded. As the “base polygonal cross-section” is also the cross-section of the opening obtained through the hollowing processing, it may have a polygonal cross-section with rounded corners. In such a case, when viewed objectively, it is difficult to distinguish between the “base polygonal cross-section” and the “substantially polygonal shape”.

Accordingly, it is difficult to distinguish the “substantially polygonal shape” of the Invention from the “base polygonal cross-section” thereof, and the technical scope of the Invention is unclear.

6. Consideration

This case teaches us to consider the following points in practice.

• As in the case of the “polygonal shape (base polygonal cross-section)” and the “substantially polygonal shape”, if a term “XX (without ‘substantially’)” and a term “substantially XX” cannot be considered the same, i.e., if there is a boundary defining a technical scope between them, the expression of “substantially XX” should be avoided.

• However, in general, the expression of “substantially XX” itself does not have disadvantages, but rather, such expression is very useful because it can expand the interpretation of the term “XX”. However, if the definition thereof is unclear, as in the case of this article, the term “substantially XX” may cause problems. Therefore, based on the two terms being considered the same, it is important to clearly state definitions (e.g. what forms are included in the expression of “substantially XX”) in the specification.

Edited by Makoto Iwata

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