August 13, 2019

Patent news

Tokyo District Court finds patent infringed under Doctrine of Equivalents despite claim amendment during prosecution

On December 21, 2018, the Tokyo District Court held that a patent is infringed under the Doctrine of Equivalents, even though a claim element that was found to be not literally infringed was added by an amendment made during prosecution of the patent (Tokyo District Court, Case No. 2017 (wa) 18184).

Background
The Plaintiff (Olympus Terumo Biomaterials Corporation) owned a Japanese patent entitled "spreader for osteotomy" (Patent No. 4736091) (the "Patent"). The invention claimed in Claim 1 of the Patent (the "Patented Invention") was as follows:

1. A spreader for osteotomy to be inserted into a cut made in the deformed femur or tibia of a patient with knee osteoarthritis, and to open the cut so as to make a space that allows insertion of an implant, comprising:
2. two pairs of swinging members which are respectively connected in a relatively swingable manner by hinge parts disposed at the distal end; and
3. two opening/closing mechanisms which open/close these two pairs of swinging members respectively about the axes of the hinge parts,
4. wherein the said two pairs of swinging members are detachably assembled in the axial directions of the hinge parts,
5. wherein one pair of said two pairs of swinging members is provided with engaging parts which are to be engaged with the other pair of the swinging members when assembled with the other pair of the swinging members.

Claim element E (underlined above) was added by an amendment during prosecution of the Patent, in response to an office action (a notice of grounds for refusal) issued by an Examiner of the Japan Patent Office (the "JPO").

In the office action, the JPO Examiner cited a prior art reference, and stated that the claimed invention could be easily invented based on such a prior art reference. In response, the applicant amended the claim to add claim element E, and also stated in a written submission that:

• "the claimed invention as amended is different from the invention disclosed in the prior art reference in a sense that it has two pairs of swinging members, and also that one pair of said two pairs of swinging members is provided with engaging parts which are to be engaged with the other pair of the swinging members. ... On the other hand, the prior art reference cited by the Examiner discloses an assembly that has one pair of jaws."

The Defendant (HOYA Technosurgical Corporation) produced spreaders for osteotomy named "HBT166P" (the "Defendant Product(s)") and leased the Defendant Products to doctors.

The Plaintiff brought a patent infringement action against the Defendant before the Tokyo District Court, and asserted that the Defendant's act of producing and leasing the Defendant Products infringed the Patent. The Plaintiff sought injunction against the Defendant.

The Plaintiff argued that the Defendant Product literally met all claim elements of the Patented Invention, including claim element E. The Plaintiff also argued in the alternative that, even if the Defendant Product did not literally meet claim element E, the Defendant Product still infringed the Patent under the Doctrine of Equivalents.

Tokyo District Court Judgment

The Tokyo District Court, Civil Division No. 40 (the "Court") found that the Defendant Product literally met all claim elements of Claim 1 of the Patent, except for claim element E.

With respect to claim element E, the Court found that the Defendant Product did not have "engaging parts" in one pair of two pairs of swinging members, and thus did not literally meet claim element E.

In the Defendant Product, the two pairs of swinging members were fixed to each other using an attachment and an angular adjustment, which enable the two pairs of swinging members to open together. However, the attachment and the angular adjustment were not "parts" of the swinging members, but rather members that were separate from the swinging members. Thus, the Court found that the attachment and the angular adjustment were not "engaging parts".

Next, the Court looked into whether the Defendant Products infringed the Patent under the Doctrine of Equivalents.

Under the case law of the Supreme Court of Japan (the so-called "Ball Spline Bearing Judgment", issued on February 24, 1998), even if there is a part in the claim that is literally different from the accused products or processes (the "products"), there is infringement under the Doctrine of Equivalents if the following five requirements are met:

1. the part is not an essential part of the patented invention;
2. by replacing the part with a part in the products, the purpose of the patented invention can be achieved and an identical function an effect can be obtained;
3. a person skilled in the art could easily come up with the idea of such replacement at the time of production of the products;
4. the products are not identical to the technology in the public domain at the time of the application of the invention or could not be easily conceived by a person skilled in the art at that time; and
5. there are no special circumstances, such as that the products were intentionally excluded from the scope of the claim during patent prosecution.

The Court found that the first three requirement are met. The Court found that the difference between the Patented Invention and the Defendant Product is merely whether the "engaging parts" are parts of one of the two pairs of the swinging members or are members separate from the swinging members. The Court found that such a difference is not an essential part of the Patented Invention.

Also, the Defendant did not dispute the fact that the fourth requirement was met.

With respect to the fifth requirement, the Defendant argued that the Plaintiff intentionally excluded the Defendant Product from the scope of the claim, when it amended the claim in response to an office action issued by the JPO Examiner and stated in the written submission that "the claimed invention is different from the invention disclosed in the prior art reference in a sense that it has two pairs of swinging members, and also that one pair of said two pairs of swinging members is provided with engaging parts which are to be engaged with the other pair of the swinging members".

However, the Court denied the Defendant's above argument. The Court found that the purpose of the statement in the written submission above was to explain to the JPO Examiner that the prior art reference merely disclosed one pair of swinging members, while the claimed invention combined two pairs of swinging members and provided engaging parts for engaging one of the two pairs of the swinging members with the other pair of the swinging members, and thereby enabled two pairs of the swinging members to open together. The Court also found that there is nothing in the written submission that indicates the issue of whether the "engaging parts" are parts of one of the two pairs of the swinging members or are members separate from the swinging members. Based on above, the Court found that the Plaintiff did not intentionally exclude the Defendant Product from the scope of the claim by making such an amendment.
Accordingly, the Court found that the Defendant Product infringed the Patent under the Doctrine of Equivalents.
The Defendant also argued that the Patent is invalid, but the Court denied the Defendant's invalidity argument.
As a conclusion, the Court found the Patent infringed and valid, and granted an injunction.

Comment

As explained above, one of the requirements for finding patent infringement under the Doctrine of Equivalents is that there should be no special circumstances such as that the products were intentionally excluded from the scope of the claim during patent prosecution (the fifth requirement of the Doctrine of Equivalents). It is understood that this fifth requirement provides a "file-wrapper estoppel" in the context of the Doctrine of Equivalents.

The most typical case in which such "intentional exclusion" is found is when a JPO Examiner issues an office action and cites a prior art reference, and an applicant amends a claim in order to avoid such a prior art reference. However, courts seem to have different views on whether "intentional exclusion" should almost always be found as long as the claim was amended under such circumstance, or they should look more closely into the context in which the amendment was made.

In the current case, claim element E was added by an amendment in response to an office action that cited a prior art reference. If we take the view that "intentional exclusion" should almost always be found as long as the claim was amended under such circumstance, it is likely that "intentional exclusion" would be found (and thus it would be found that the fifth requirement of the Doctrine of Equivalents is not met) in the current case. However, the Tokyo District Court in the current case did not take such a view, but rather looked more closely into the context in which the amendment was made (by taking into account what the applicant stated in the written submission submitted by the applicant at the same time as the amendment), and concluded that there was no "intentional exclusion".

On appeal, the Intellectual Property High Court (the "IP High Court") found that the Defendant Product literally met claim element E, and affirmed the Tokyo District Court judgment (IP High Court, Case No. 2019 (ne) 10005. Judgment issued on July 24, 2019). Although the IP High Court reached the same conclusion as the Tokyo District Court, it did not go into the issue of the Doctrine of Equivalents. However, it would be interesting to see whether other courts in other cases would follow the Tokyo District Court's view, or take different views on the issue of "intentional exclusion".

Written by: Mr. Yusuke Inui (Attorney-at-Law (Japan, New York), Patent Attorney (Japan))