Federal Circuit Upholds District of Delaware’s Summary Judgment Ruling for Donghee

By Butch Laker
December 10, 2019

“The CAFC concluded that the district court did not err in its summary judgment of no literal infringement because there were undisputed differences between the patents and the accused product.”

Last week, the U.S. Court of Appeals for the Federal Circuit (CAFC) issued a precedential public opinion affirming the District Court for the District of Delaware’s grant of summary judgment of noninfringement for Donghee America, Inc. and Donghee Alabama, LLC (Donghee). The CAFC held that the summary judgment ruling was consistent with the claim construction and supported by the facts on the record. A sealed opinion was delivered on November 21.

The plaintiff, Plastic Omnium Advanced Innovation and Research (Plastic Ominum), owns two patents for blow molding plastic fuel tanks, U.S. Patent Nos. 6,814,921 (‘921) and 6,866,812 (‘812). The patents outline a system to manufacture the tanks in a manner that allows accessory components to be installed without damaging or removing part of the tank’s wall. The ‘812 patent describes a method in which a hollow plastic tube, called a parison, is extruded, formed, and then cut by a blade at the exit of the extruder. The dispute arises out of the ‘921 patent’s description of an “extruded parison” limitation:

  1. A process for manufacturing plastic hollow bodies from two shells formed by molding, which are joined together, at least one shell being produced by compression-molding a portion of a plastic sheet between a mold and a punch and by the remaining portion of the sheet being blow-molded in the region not compression-molded, characterized in that it is applied to the manufacture of a fuel tank and in the sheet is obtained in the same manufacturing line as the shell which will be produced from this sheet, by the cutting and opening an extruded parison of closed cross section.

Plastic Omnium brought suit against Donghee for infringement of eight patents, including the ones mentioned above. Donghee moved for summary judgement of noninfringement after the claim construction. During claim construction, the term “parison” was disputed, with Donghee asserting “that it should be given its plain and ordinary meaning of ‘hollow plastic tube exiting the die of an extrusion head.’” Plastic Omnium contended that it acted as its own lexicographer and did not intend to use the conventional meaning of “parison” in its ‘921 and ‘812 patents. The district court agreed with Plastic Omnium, reasoning that “the patents specify that the ‘parison’ is cut in two as it leaves the die at the end of the extrusion head[,]” and therefore, can’t be held to the original definition of a fully-formed plastic tube.

The district court identified that the main issue was with respect to the point at which the extruded plastic becomes a parison and identifying the location of the die. Plastic Omnium claimed that the process included the splitting of the plastic within the extrusion head or the die itself. Donghee and the district court disagreed, indicating that neither patent mentions cutting the parison until it exits the die/extrusion head.

District Court Analysis

Donghee motioned for summary judgment for noninfringement of five patents, including the two on appeal. Donghee argued that its product does not infringe on patents ‘921 and ‘812 because it “does not extrude a parison” using the general concept of a parison. The district court recognized the similarities in the accused product, where a manufacturing process forces molten plastic through an extrusion head, and then feeding that plastic into a die, which then cuts the plastic into two sheets. In its analysis, the court turned to the claim construction in the holdings. It outlined three main assertions of Plastic Omnium as:

(1) The parison “may be cut as it exits the die at the end of the extrusion head.

(2) A preformed tube, even if it is split before the extrusion head, will be within the scope of the claim

(3) “The die must be located at the extrusion head’s lowest point.”

According to the district court, the claim construction makes clear the splitting of the plastic tube “must not occur inside any of the extrusion head/die equipment.” The court determined Donghee did not literally infringe any assertions of the patent claim because its accused product uses a separate “flat die” tool to cut the plastic parison after it is extruded. The accused product also did not infringe under the doctrine of equivalents because a reasonable jury could not find the cutting of the parison is insubstantially different when cut inside the extruder versus outside the extruder.

Literal Infringement

Plastic Omnium challenged the district court’s grant of summary judgment of no literal infringement and no infringement under the doctrine equivalents by appealing to the Federal Circuit.

Plastic Omnium argued that the court granted summary judgment on an “erroneous claim construction[,]” and improperly placed a cutting location requirement. The CAFC disagreed. Plastic Omnium argued the district court erred in claim construction when it required the parison be cut outside of the extrusion head, therefore excluding Donghee’s application. The CAFC maintained the district court’s decision. “Claim 1 of the ’921 patent requires ‘cutting and opening of an extruded parison of closed cross section.'” The ‘812 patent similarly describes an “extruded parison,” which the district court deemed to exclude any preform or molten plastic inside the extrusion head.

While the flat die does create two sheets from a parison, those sheets are not cut outside of the extruder. Instead, these two sheets are injected from the extruder into a die mounted to the head.  The CAFC held that Plastic Omnium’s use of the term “parison” in its patents did not match the conventional use of the word. Thus, they must determine whether the accused product falls within the scope of this new definition.

The CAFC reasoned the main disagreement was at what point the molten plastic within the extrusion head became a parison. The CAFC was unmoved by Plastic Omnium’s contention that the “extruded parison” could be split inside the die. The CAFC maintained that the claim construction makes clear that the splitting necessarily could not occur in the die, be it separate or joined to the extrusion head. Because Donghee uses a mounted flat die, no tubular parison is extruded from the extrusion head. Molten plastic instead passes through a “spiral mandrel” directly into the flat die and thusly, does not qualify as an “extruded parison” under the court’s claim construction.

Doctrine of Equivalents and Application

Plastic Omnium argued that the district court erred in its granting of summary judgment on the ground of the doctrine of equivalents because it improperly read in a cutting location requirement and ignored that the steps in the claimed process and in the accused product were the same no matter where the splitting of the parison occurs. Looking to AquaTex, “[a] finding of infringement under the doctrine of equivalents requires a showing that the difference between the claimed invention and the accused product or method was insubstantial or that the accused product or method performs the substantially same function in substantially the same way with substantially the same result[.]”

The CAFC reviewed a testimony by Plastic Omnium’s expert, Dr. Osswald, where he admitted that “Donghee’s flat die tool may offer improvements over… the Asserted Patents.” Plastic Omnium ultimately “failed to present evidence as to why the differences between the touted advantage of uniform wall thickness in the ’812 and ’921 patents and the capability of independent wall thickness manipulation in the accused product were insubstantial” and  thus “failed to demonstrate a genuine dispute of material fact that would prevent the grant of summary judgment as to the doctrine of equivalents.”

The CAFC concluded that the district court did not err in its summary judgment of no literal infringement because there were undisputed differences between the patents and the accused product. Similarly, the Court could not prevent the summary judgment under the doctrine of equivalents because Donghee’s process significantly improved on the method outlined in patents ‘921 and ‘812. The district court decision was affirmed on both counts.


Judge Raymond Clevenger dissented, arguing that the majority’s analysis “elides the key factual dispute: Does Donghee’s accused process have more than one die?” In his view, Plastic Omnium had “presented sufficient evidence to create a material factual dispute over the structure of Donghee’s extrusion head” and the district court “took its eye off the ball.”

“The district court deprived Plastic Omnium of its day in court, and the majority perpetuates that error,” wrote Clevenger.


The Author

Butch Laker

Butch Laker is a 1L student at UNH Franklin Pierce School of Law. He is also the elected 1L governor for the Patent Law Forum on campus. Before law school, he attended Purdue University, where he majored in Physics. He hopes to combine his passions for science and law as he pursues a career in patent law.

Warning & Disclaimer: The pages, articles and comments on IPWatchdog.com do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of IPWatchdog.com. Read more.

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There are currently 2 Comments comments.

  1. TFCFM December 11, 2019 9:52 am

    This is a nice summary of a complicated case.

    The one utter quibble that I have is also a pet peeve of mine:

    BL: “Donghee motioned…

    While this is *permissible* English, it makes the hair on the back of my neck stand up whenever I hear it. One does not “motion” or “make a motion;” instead, one “moves.”

    In another set of comments here, someone postulated that I might be a certain kind of judge. I wish this were so, in order to live out a longtime fantasy: The next time I heard counsel announce, “I’d like to make a motion…,” I could instruct counsel to approach the bench, turn around, and bend over so I could take a switch and “make a motion” that would help counsel remember to “move,” rather than to “make motions.”

    Sorry to rant about a quibble, though. Nape hair settling back down. Coffee good.

  2. Butch December 12, 2019 1:21 pm

    @TCFM, Thank you for the comment. I will be more selective with my word choice continuing forward. Any advice is welcome as I am always looking to improve my writing.