A patentable invention must be "new" as of the filing date. Public disclosure before filing - selling, advertising, exhibiting, or posting about it on social media - can destroy that novelty and make it unpatentable. Thai law provides only a narrow exception in limited circumstances. Where possible, file before disclosing anything, and consult a patent agent immediately if disclosure has already occurred.
Why "novelty" matters
Under Patent Act B.E. 2522, Section 5, a patentable invention must satisfy 3 requirements: novelty, an inventive step, and industrial applicability. Section 6 defines novelty by reference to what counts as prior art, in 5 categories: (1) an invention widely known or used by others in Thailand before the filing date; (2) an invention whose subject matter was described in a document or publication, or displayed or otherwise disclosed to the public, in Thailand or abroad, before the filing date; (3) an invention already patented or petty-patented, in Thailand or abroad; (4) an invention applied for abroad more than 18 months before the Thai filing date, where no patent or petty patent has yet been granted for it; or (5) an invention already applied for where that application was published before the filing date. The critical point: novelty is assessed as of the filing date, not the date the invention was conceived - a single disclosure before that date can matter.
What kinds of disclosure can put novelty at risk
Section 6(2) covers disclosure of an invention's substance to the public in almost any form, in Thailand or abroad. Common, higher-risk examples include:
- Selling - offering for sale or selling a product embodying the invention, even in small quantities.
- Advertising - publishing details of the invention through ads, a website, or a product catalog.
- Exhibitions - showing a prototype or product at a general trade show that doesn't meet the narrow exception described below.
- Investor presentations - disclosing technical details while fundraising, without a confidentiality agreement in place.
- Academic publication - a paper, thesis, or conference poster made available to the public.
- Social media - posting images, video, or details of the invention on a public platform.
- Product demonstrations - demonstrating how the invention works to a general audience.
- Disclosure to manufacturers or suppliers - sending drawings or specifications for a manufacturing quote without a confidentiality agreement.
Each of these carries a different level of risk, depending on whether the recipient was genuinely the public or the disclosure was kept within a defined, confidential scope - see the next section.
Confidential disclosure vs. non-confidential disclosure
Section 6(2) uses the phrase "disclosed to the public." A disclosure that remains genuinely confidential generally would not be treated as disclosure to the public in that sense. That confidentiality can come from a written non-disclosure agreement (NDA), or, depending on the facts and the applicable law, from another enforceable duty or confidential relationship - for example, a professional or fiduciary relationship. Whether any particular disclosure was "genuinely confidential," though, is a fact-specific question: whether the agreement or duty is legally binding, how narrow the group of recipients is, and whether the recipients actually complied with it. It is not an automatic conclusion that applies the same way in every case.
The role and limits of NDAs
An NDA can help document confidentiality and meaningfully reduce novelty risk in practice, but it isn't a complete shield and doesn't guarantee preservation of patent rights in every jurisdiction. Its limits are worth knowing: a recipient can still breach it and disclose further, leaving you to prove damages after the fact; a loosely drafted NDA may not actually cover the information that gets disclosed; disclosure made in a meeting or public setting can reach people beyond the counterparty you signed with, even unintentionally; and an NDA is a matter of contract rights, not patent law directly - it doesn't itself create or guarantee an invention's novelty.
Why filing before public disclosure is generally safer
Because the scope of the Section 6 exception is narrow and carries interpretive uncertainty (see below), the safest practical approach is to complete your patent filing before disclosing the invention publicly in any form. Once filed, the filing date becomes the date novelty is assessed against - disclosure after that date no longer affects the application you've already filed.
Thailand's statutory exception
The final paragraph of Section 6 of the Patent Act B.E. 2522 provides that certain disclosures do not count as "disclosure" that destroys novelty under Section 6(2), provided the application is filed within 12 months of that disclosure. The circumstances the statute covers are: (1) disclosure resulting from the invention having been obtained unlawfully; (2) disclosure made by the inventor themselves; and (3) disclosure resulting from the inventor displaying the invention at an international exhibition or an official exhibition.
This exception, however, only applies to a Thai filing. Other countries may apply different or narrower novelty and disclosure-exception rules of their own. Filing before any public disclosure therefore remains the safest practical approach whenever possible, and a registered patent agent should assess whether the facts of any specific situation actually fall within the exception above before you rely on it - and even where it applies, the application must still be filed within 12 months of the disclosure.
Steps to take if disclosure has already occurred
If an invention has already been disclosed, intentionally or not: stop any further disclosure immediately; record the date, nature, and audience of the disclosure in as much detail as you can recall; contact a registered patent agent as soon as possible to assess whether the Section 6 exception might apply; and consider filing as quickly as possible if you're still within any relevant window. Don't assume on your own that the right is lost, or that it's still safe, without a professional assessment.
International filing implications
If you also plan to file in other countries, note that novelty rules and disclosure exceptions vary by each country's own law. A disclosure that doesn't affect a Thai application (because it falls within the narrow exception above) could still destroy novelty elsewhere, and vice versa. Plan your target filing countries before any disclosure takes place, and consult patent counsel in each target jurisdiction separately about that country's own novelty rules. (The 12-month priority right under the Paris Convention, which lets a later foreign filing claim the benefit of an earlier filing date, is a separate concept from the novelty exception discussed above.)
Decision Checklist
- Nothing has been disclosed yet - file before disclosing whenever possible. This is the safest approach.
- You need to disclose to a manufacturer, investor, or business partner - put a clearly scoped NDA in place before every disclosure, limit recipients to who genuinely needs to know, and keep a copy of the signed agreement.
- You're planning to exhibit at a trade show - check whether the event qualifies as an "international exhibition or official exhibition," remember you must still file within 12 months of the disclosure, and keep evidence of the exhibition date.
- Disclosure already happened by accident - contact a patent agent immediately to assess what options remain. Don't wait.
- You're also planning to file abroad - consult patent counsel in each target country separately about that country's own novelty rules.
