nanalLabs BlogPlenty of researchers only start looking into patenting after they've already presented at a conference or published a paper — "wait, could this be patentable too?" By the book, that's too late: Korean patent law denies a patent for an invention that was disclosed before filing. There is an exception, though. Search "grace period claim" (공지예외주장) and most results stop at "file within 12 months," but the actual rule splits into two procedural tracks, a missed filing step voids the claim by itself, and the exception doesn't reach past the scope of what was actually disclosed. This post walks through all three.
The default rule is unforgiving — disclose first, lose the patent
Article 29(1) of the Korean Patent Act denies novelty to an invention that was publicly known, publicly worked, or described in a distributed publication, domestically or abroad, before filing. A journal publication, a conference talk, a demo at an exhibition, press coverage, even handouts at an investor pitch can all count as "disclosure" here. The fact that the inventor is the one who disclosed it doesn't change this default rule.
The grace-period claim splits into two tracks
Article 30 of the Patent Act ("inventions not deemed to have been disclosed") carves out an exception: meet certain requirements and the disclosure is excluded from prior art. But the procedural requirements differ depending on why the disclosure happened.
| Article 30(1)(i) | Article 30(1)(ii) | |
|---|---|---|
| Who disclosed it | The right holder disclosed it themselves (paper, conference, exhibition, demo, etc.) | Disclosed against the right holder's will (leak, theft, mistake, etc.) |
| Filing deadline | Within 12 months of disclosure | Within 12 months of disclosure |
| Must state intent in the application | Yes, required | No such requirement in the text |
| Proof documents | Must be submitted within 30 days of the filing date | No mandatory deadline, though preparing them is advisable in case of a dispute |
Item (i) is the one that comes up overwhelmingly often in practice — it covers the most common situation: a researcher publishing a paper or presenting at a conference themselves. The catch is that missing either of the two procedural steps — stating the intent in the application, or submitting proof within 30 days — invalidates the claim outright.
How to actually file one
At filing, you state the intent to invoke the grace-period claim in the application's bibliographic section, then submit the original proof documents to the Korean Intellectual Property Office within 30 days of the filing date. Common proof documents include a publication confirmation or offprint of the paper, conference presentation materials or the abstract booklet, an exhibition catalog, a press release, or pitch materials — anything that can pin down "when, and what was disclosed." That 30-day window runs out fast once the filing clock starts, so if you haven't kept your disclosure history organized beforehand, it's hard to assemble the documents in time.
What the grace period doesn't cover
A grace-period claim only reaches the same scope as what was actually disclosed. Anything added or improved after the disclosure gets evaluated for novelty and inventive step on its own. Say a conference poster reports results from a specific composition or process, and a few months later the filing adds conditions with significantly improved numbers — that improvement may not be provable as within the disclosed scope just from the presentation materials. Whether the improvement was already known at presentation time becomes a separate point of dispute.
There's another trap if you're planning to file abroad: grace periods vary by country. The European Patent Office generally does not recognize a grace period for self-disclosure, carving out only narrow exceptions like exhibiting at an officially recognized international exhibition. So even if a domestic grace-period claim saves your Korean filing, the same invention may have already lost novelty by the time you file in Europe. If foreign filing is on the table, the safer move is delaying disclosure itself as long as possible.
Why records matter — you have to prove the timing and scope yourself
For a grace-period claim to hold up, the applicant has to specify and prove, on their own, "when, what, and how much" was disclosed. Presentation materials or a paper manuscript prove that the content was disclosed, but they often don't prove where the line falls between what was in the presentation and what was developed afterward — how far the work had actually progressed at the time of the presentation. When that boundary becomes contested, dated internal records kept before the disclosure — a research notebook or development log — serve as evidence of "what was known at that point in time."
Checklist before filing
- [ ] Is it still within 12 months of the disclosure date?
- [ ] Did the application state the intent to invoke the grace period (item (i))?
- [ ] Can the proof documents be ready within 30 days of the filing date?
- [ ] Have you checked how far the disclosed content overlaps with the filed claims?
- [ ] If foreign filing is planned, have you separately checked whether the target country recognizes a grace period at all?
Bottom line
A grace-period claim reverses the default conclusion that "disclosing first means giving up the patent" — but miss the deadline or skip a procedural step and the claim is void on its own, and it never reaches improvements made beyond what was actually disclosed. Check the exact text of Article 30 and the Korean Intellectual Property Office's own guidance for the precise requirements and current forms.