May 17, 2021
Are Divisional Applications Useful in Patent Infringement Lawsuits?

MIYOSHI & MIYOSHI
Vice Chairman: Shunichi Takahashi

With regard to the status of patent applications accepted by our firm, the number ofdivisional applications seems to be increasing. As shown in FIG. 1, data from the JPO shows
the number of divisional applications is on the increase.

I think this is because divisional

applications are recognized as a useful means for utilizing patent rights; however, is thisobjectively true?

In fact, although there may be some differences in research and analysis targets,I have read both articles insisting that the winning rate of patent infringement litigation involving
divisional applications is higher than that of patent infringement litigation involving nondivisional patent applications, and conversely articles insisting that the winning rate of patent
infringement litigation involving divisional applications is lower.
find out what the truth is.
FIG. 1

So, I did my own research toAs research targets, civil lawsuits (including civil provisional dispositions), excluding
administrative lawsuits (lawsuits for revocation of trial decisions), which were decided by theTokyo District Court, the Osaka District Court, and the Intellectual Property High Court between
January 1, 2009 and December 31, 2020, were targeted based on the Supreme Court's casebook
on intellectual property disputes. Of course, cases of employee invention and cases of breach ofcontract, which are unrelated to infringement cases, were excluded.
The results are shown in FIGS. 2 and 3.

FIG. 2 shows the transition in each of theabove years regarding:‣ the percentage of cases won by patentees in patent infringement lawsuits using patentrights acquired through divisional applications (hereinafter referred to as "divisionalcases"); and‣ the percentage of cases won by patentees in patent infringement lawsuits using patentrights acquired through ordinary patent applications (hereinafter referred to as "nondivisional cases").
FIG. 3 shows the transition in the number of lawsuits, the number of non-divisional
cases, the number of divisional cases, and the percentage of divisional cases in each of the aboveyears.
FIG.2

FIG.3I think that the following points can be identified based on FIGS. 2 and 3.
1.

According to FIG. 2, it can be seen that the percentage of winning lawsuits indivisional cases is not necessarily lower than that of winning lawsuits in non-divisional cases.
Overall, the percentage of winning lawsuits in divisional cases tends to be higher than that ofwinning lawsuits in non-divisional cases.
2. According to FIG. 3, it can be seen that the number of non-divisional cases has also
decreased since 2014 as the total number of lawsuits has decreased, while the number of divisional
cases has remained the same or increased.

As a result, the percentage of divisional cases out of

the total number of lawsuits seems to be increasing.
In view of the fact that one of the purposes of using divisional applications is to acquire
patent rights so that a competitor's future products, etc. fall within the technical scope of the patentrights, it is understandable that the percentage of winning lawsuits in divisional cases is higher
than that of winning lawsuits in non-divisional cases. As a result, it is understandable that thepercentage of divisional applications is on the increase.

Therefore, it can be said that divisional

applications are also useful as a means for utilizing patent rights.
Meanwhile, in lawsuits involving divisional applications, divisional requirements,
which question whether or not a divisional application has been legally filed, can easily become

an issue.

If a divisional application violates the divisional requirements, a patent will beinvalidated for reasons such as violation of novelty, whereby it is natural for defendants in thelawsuits to insist that the divisional application meets the divisional requirements. However, outof the 195 divisional cases surveyed at this time, only 20 cases (10.3%) were judged in relation
to the divisional requirements. Then, out of the 20 cases, 14 cases (70%) were determined asmeeting the divisional requirements, and 6 cases (30%) were determined as not meeting thedivisional requirements.

These figures suggest that, as a patentee, naturally the contents ofdivisional applications are sufficiently described before proceeding with lawsuits, which isconsidered to be one of the reasons for an increase in the winning rate of lawsuits. In fact, manyof the divisional applications used in the lawsuits were selected from among multiple divisional
applications filed from an original application.
In this way, it can be said that the trend of acquiring patent rights based on divisional
applications with narrow targets, such as future products of competitors, and actively using suchpatent rights as useful evidence to win lawsuits is one typical example of making effective use ofpatent rights, and it has been said that this trend has been insufficient in the past. Thus, suchpatent rights making it possible to realize this trend can be said to be high-quality patents.
However, looking at the number of cases in FIG. 3, it cannot be said that there are many cases inwhich this trend has been achieved, and the number of patentees who are able to make effective
use of such high-quality patent rights still seems to be small. I believe that there is room toreview patent strategies using divisional applications.
There are some applicants who are pleased with a decision for a patent to be grantedwithout reasons for refusal being issued (a so-called one-shot registration), but it is notnecessarily a good idea to acquire patent rights early in spite of the fact that there is no plan toutilize such patent rights, and it should be kept in mind that the use of divisional applications tokeep patent applications pending is useful in terms of patent strategy.
End.