Why the interpretation of technical terms in patent claims is important

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The validity of Chinese patent ZL200780042463.2 entitled “Thermosetting resin composition for light reflection and its manufacturing method, and the substrate for mounting optical semiconductor elements and the optical semiconductor device using such a resin composition” was challenged before the China National Intellectual Property Administration (CNIPA), as the patent owner attempted to enforce the disputed patent against an alleged infringer in the Beijing IP Court.

Claim 1 of the patent in suit protects a thermosetting resin composition for reflecting light, characterized in that:

the burr length generated in transfer molding at a mold temperature of between 100 °C and 200 °C, a molding pressure of not more than 20 MPa and a molding time of between 60 and 120 seconds is not more than 5 mm.

The interpretation of the ridge length was the point of contention in both the nullity and civil infringement proceedings.

The interpretation of claims is based on the court’s assessment of whether an allegedly infringing technical solution falls within the scope of protection of a patent. However, the interpretation of claims is not limited to infringement disputes, as it is also necessary to interpret claims in patent prosecution proceedings in order to determine the meaning and scope of the claims and their connection with the prior art.

As a general principle, the judiciary often refers to the description and accompanying drawings, relevant claims and the examination file of the patent in question to interpret the claims. Where any terminology in the claims is specifically defined in the specification, the definition takes precedence. Should the above means not explain the meaning of the claims, another possibility is to consider known literature, such as reference works, textbooks and the like, as well as the ordinary understanding of the person skilled in the art.

The CNIPA Guidelines for Patent Examination specifically provide the following in Part II, Chapter 2, Section 2.1.1:

The description must use terms from the technical field to which the invention or utility model relates. The description must accurately reflect the technical content of the invention or utility model, without any ambiguity or ambiguity that could prevent a person skilled in the art from clearly and correctly understanding the invention or utility model.

The Guidelines also set out in Part II, Chapter 2, Section 3.2.2 the principle of how a statement should be understood:

The scope of a claim is to be construed according to the meaning of the words used in the claim. In general, the words used in a claim should be understood to have the meaning they normally have in the relevant art. In special cases in which the description expressly assigns a particular meaning to a certain word and, based on the definition of the word in the description, the scope of protection of the claim using the word is sufficiently clearly defined, such a case is also admissible.

Definition of the burr length in the patent specification

Paragraph 0072 refers to the fact that, as used in the present invention, “burr length during molding” means the maximum length of a resin-cured product that protrudes in the radial direction from a central cavity in a mold through gaps at the joint between the facestock paint and the bottom color of the mold during the transfer molding process by using the mold for flash measurement as shown in Figure 4.

Paragraphs 0139 and 0140 indicate that the flash measurement mold comprises a pair of dyes, namely an upper dye 400 and a lower dye 401 . The upper colorant 400 has a resin sprue 402 . The lower die 401 includes a cavity 403 opposite the resin gate 402 and six slits 404, 405, 406, 407, 408 and 409 extending from the cavity 403 to the outer periphery of the mold. The width of the six slits extending from cavity 403 was five mm and the depths were 75, 50, 30, 20, 10 and 2 µm, respectively. As shown in Figure 5, ridges are indicated at 410 which are formed by the resin composition flowing over the outer edge of the cavity 403 along the slots and being cured. The burr length specified in the present invention is the maximum value of the burr denoted by reference numeral 410 as measured with calipers.

inconsistency in the description

Based on the description, the length of the ridges refers to the maximum length of the resin composition that flows and is cured along the slits (ie, the six slits with different depths). However, as the drawings show, this is not the case. In Figure 5(b), the ridges are labeled 410 and marked between slots 407 and 408 rather than within the slot. Fig. 5(a) also differs from Fig. 5(b): if the ridges refer to those labeled 410 in Fig. 5(b) which are between the slots, then they should be above (rather than below). ) to be positioned on the upper surface of the lower dye in Figure 5(a). When the ridges refer to the hardened part inside the slits, considering that all slits have a certain depth and extend to the outer edge of the lower dye, the lines indicating the depth of the slits should instead refer to extending to the outer edge of the lower dye to end at the outer edge of 410. In short, Fig. 5(a) is defective in both cases.

Importance of burr length in prior art

Without generally recognized importance in the art, only the length of the ridges is referred to in some Japanese patent literature.

In JP2007-119547A, the test die has slits with a depth of 2 μm, 3 μm, 5 μm, 10 μm, 20 μm, 30 μm and 50 μm, and the length of the burrs refers to the maximum length of the resin composition contained within the six slits (excluding the 50 μm deep slit).

In JPS56-149454A, the test form has slits with depths of 100 μm, 50 μm, 30 μm, 20 μm and 10 μm, and the lengths of the burrs are measured in each slit.

In JPH07-179729A, the test form has slits with a depth of 10 μm, 30 μm, 50 μm, 75 μm and 100 μm, and the length of the burrs refers to the length inside the 75 μm deep slit.

The burr length inspection methodology as defined in the specification of the patent in suit is consistent with that mentioned in the prior art, ie inspection of the burrs within the slots.

The second part of this article examines the decision on the invalidity of the patent in question.

Xiaoping Wu

Intellectual Property of Wanhuida

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