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The Prosecution History Estoppel in Patent Infringement Litigation
Time: 2015-07-03
The Prosecution History Estoppel in Patent Infringement Litigation

Details about the case:

Comyan Lighting Electrical Appliance Co., Ltd is a high-tech company which is specializing in manufacturing many kinds of electric light source products. In 2011, Comyan received a court summon from Jiangmen Intermediate People’s Court and was accused of infringing the utility model patent right of another Guangdong company about the production of a quartz disinfecting bulb. Therefore, Comyan entrusted Jiaquan IP Law Firm with responding to the suit.

After being entrusted, Jianming FENG, an experienced patent attorney in Jiaquan further studied the case and found out that the patentee had abandoned the technical solution about the forming of a crush resistance sealing on one end of the gas-tight container in the patent protection scope. The only technical solution requested protection in this patent was that the sealed vitreous body and the shell of the bulb were two independent units. The products accused of infringing the patent right were applying the abandoned technical solution. Therefore, they did not fall into the protection scope of the patent. In response to the suit, Jiaquan submitted proper evidence and argued in the above respects. Finally, to avoid the long time wasted for the litigation proceedings, the plaintiff accepted to end the suit by reconciliation.

Legal grounds:

The Supreme People's Court’s Interpretation on Problems in Laws Application of Handling Patent Infringement Litigation Cases

Article 6  The People’s Court shall not approve the technical solutions which were abandoned by the applicants or patentees in the allowance or invalidation proceedings by claims amendments, specification amendments or opinion statements, but claimed protection in the patent litigations.


Jianming FENG of Jiaquan IP Law Firm: The prosecution history estoppel is a restriction to the doctrine of equivalents. It precludes the patentees from invoking the doctrine of equivalents to the abandoned scope of their claims.

The applicants or patentees may make amendments or restrictions to, or stress on some of the technical features in the scope of their claims for granting the patent right. However, they would like to cancel these restrictions and claim protection of the abandoned scope by invoking the doctrine of equivalents, for the preclusion of which, the prosecution history estoppel is made.

From Jiangmen Daily

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