Procedure for Responding to a Patent Infringement Warning

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Select your current step and the content for that step will appear below.

1. 1Receiving the warning letter
2. 2Validity and infringement analysis
3. 3Reply and negotiation
4. 4Requesting a trial
5. 5Receiving the complaint and written answer
6. 6Hearings and technology explanation session
7. 7Judgment
8. 8Appeal and final appeal

• Basic step
• Additional action / option
• Rejection / objection
• End of procedure

Time required

The time to analyze and reply to a warning letter varies by case, and the length of IPTAB trials and 1st-instance infringement lawsuits also varies by case

Cost

Invalidation trial fee of KRW 150,000 per case (electronic filing) plus KRW 15,000 for each claim in dispute. The defendant in a lawsuit pays no stamp fee (court fee) (no stamp is attached to a written answer). Appraisal fees apply if there is an appraisal, and patent attorneys' and lawyers' fees are set by the engagement contract

Procedure guide

Read from start to finish in order. Red text marks deadlines set by law.

1. 1

   The other side sends a warning letter (by certified mail) stating the patent number, the infringement claim and a demand to stop selling. The reply deadline in the warning letter is not a period set by law. However, sales after receiving the warning letter may be found to be willful infringement and become grounds for increasing damages up to 5 times the loss (Patent Act §128(8)). So record the date of receipt and start your analysis right away. The faster your analysis, the sooner you can decide whether to keep selling.

2. 2

   Check the patent register to see whether the patent is still alive. This is because if the patent has lapsed, there is no infringement issue. Then prepare a claim comparison chart that compares the elements of the claims (the items setting out the patent's scope of protection) with your product one by one. If even one element is missing, there is no infringement. At the same time, search for prior art disclosed before the patent application to examine whether there are grounds for invalidity and whether it is freely practicable technology (technology anyone may use).

3. 3

   Send a reply based on your analysis, stating your view that "there is no infringement" or "the patent has grounds for invalidity." Do not use expressions admitting infringement. This is because such expressions can be used as an admission in a lawsuit. If necessary, negotiate on terms such as a license (a right to use the patent for a fee) or a design change. If an agreement is reached, the dispute ends.

4. 4

   If negotiation is difficult, request an invalidation trial or a negative trial to confirm the scope of rights (confirming that your product does not fall within the patent's scope) at the IPTAB (Daejeon) (Patent Act §133, §135). The result of the trial is also important material for the court in an infringement lawsuit. The length of the trial varies by case. If you find the trial decision hard to accept, file a lawsuit to cancel the trial decision with the Patent Court within 30 days from the day you receive the certified copy.

5. 5

   If the other side files an infringement lawsuit, submit a written answer within 30 days from the day you receive the copy of the complaint (Civil Procedure Act §256, §257). In the answer, set out your counterarguments of invalidity, non-infringement and freely practicable technology, and dispute the damages. If you do not submit one, a judgment against you may be issued without a trial, so submit it first with your basic counterarguments even if your analysis is not quite finished.

6. 6

   At the technology explanation session, both sides present the technical details, and the court, if necessary, organizes the issues with the help of technical examiners. At the hearings, claim interpretation, comparison of elements and product appraisal are carried out. In this process, an order may be issued requiring you to submit your sales and cost records. So it is best to prepare, along with the records, an application to protect trade secrets in advance.

7. 7

   If your product does not infringe or it is clear that the patent will be invalidated, the other side's claim is dismissed. If infringement is found, the court orders a ban on production and sales, destruction and damages, and for willful infringement, the damages can be increased up to 5 times (Patent Act §128(8)). This is why sales after receiving the warning letter affect the finding of willfulness. The length of the 1st-instance trial varies by case, depending on the issues and whether there is an appraisal.

   Current step
8. 8

   Appeal to the Patent Court within 2 weeks from the day you receive the written judgment. Submit the statement of grounds for appeal within 40 days from the day you receive notice that the records have been received (Civil Procedure Act §396, §402-2). Against a Patent Court judgment, file a final appeal to the Supreme Court within 2 weeks, and submit the statement of grounds for final appeal within 20 days from the day you receive notice that the records for the final appeal have been received (§427). Each deadline starts on a different day, so keep track of them separately.

Frequently asked questions

Practical questions that come up right away in this procedure.

QDo I have to reply within the deadline stated in the warning letter?

It is not a deadline set by law, so being late does not immediately put you at a disadvantage.However, if you ignore it, the other side may go straight to a lawsuit or a provisional injunction. Also, sales after receiving the warning letter become grounds for a claim of willful infringement.So it is safest to reply as soon as your analysis is done, stating your view that "there is no infringement" or "the patent is invalid." A reply also leaves a record that you are disputing the infringement.

QDo I have to stop selling as soon as I receive a warning letter?

You are not obliged to stop. However, if infringement is found later, sales after you received the warning letter may be treated as willful infringement. In that case, damages of up to 5 times the loss can be awarded.So decide whether to keep selling or change the design after seeing the claim comparison chart and the invalidity review. This is because continuing to sell without grounds increases the risk of damages.

QWhere and how do I file an invalidation trial, and how much does it cost?

Submit a request for a trial to the Intellectual Property Trial and Appeal Board (IPTAB) (Daejeon). You can also file online through the electronic filing website "Patent-ro." The fee for electronic filing is KRW 150,000 per case plus KRW 15,000 for each claim in dispute.If filed on paper, it is KRW 170,000 per case. Other costs, such as the prior art search and the patent attorney's fees, are set by your contract with whoever you engage.

QI received a complaint, but my analysis is not finished. What do I do about the written answer?

Even if your analysis is not finished, you must submit a written answer within 30 days from the day you receive the complaint. If you do not, you may lose without a trial. First submit an answer stating that you ask for the claim to be dismissed and outlining your counterarguments.The main counterarguments are invalidity of the patent, non-infringement and freely practicable technology (technology already known that anyone may use). Details can be added later in briefs (written documents organizing your arguments).

QWhere can I check whether the other side's patent is valid?

You can check by patent number on the patent information search service (KIPRIS). It shows whether the patent is registered, the status of annual fee payments and the expiry date of its term.It also shows trial and lawsuit history, so check whether an invalidation trial (a trial to treat the patent as never having existed) is already pending. If another company has filed an invalidation trial, its result may also affect your case.

QCan I respond on my own without a lawyer?

Replying to a warning letter and requesting an IPTAB trial can be handled by a patent attorney alone. However, only a lawyer can represent you in an infringement lawsuit at a district court. So if you have a representative in an infringement lawsuit, you must appoint a lawyer.