A petty patent can be registered for any invention that is novel and industrially applicable, without needing to meet the inventive-step bar required for an invention patent. But certain categories - such as scientific and mathematical theories, naturally occurring microorganisms, or inventions contrary to public order or morality - remain unpatentable regardless of the application type.
A petty patent can be registered for an invention that has novelty and is industrially applicable - that's it. Unlike an invention patent, it doesn't need to clear the "inventive step" bar, which is why it suits incremental improvements or adaptations of existing products rather than entirely new innovations. That said, certain categories of invention remain excluded by law regardless of whether you file for an invention patent or a petty patent.
The Petty Patent Criteria: Novelty and Industrial Applicability
Under the Patent Act B.E. 2522, Chapter 3 bis on petty patents (Section 65 bis), an invention must meet two requirements to qualify for a petty patent:
- Novelty - the essential substance of the invention must not have been publicly disclosed before the filing date, whether through publication, exhibition, or public use.
- Industrial applicability - the invention must be capable of being produced or used in industry, agriculture, commerce, or handicraft - not just a theoretical concept with no practical realization.
These two criteria are the same standard used to examine invention patents. The difference is the third criterion, which a petty patent does not need to meet - see the next section.
Why a Petty Patent Doesn't Need an "Inventive Step"
An invention patent must clear an additional third bar: the inventive step - the invention must not be something a person ordinarily skilled in that field could easily come up with. A petty patent doesn't need to meet this bar, so it covers a wider range of inventions, including minor improvements on existing products that might fail an invention patent's inventive-step test but are still novel and practically useful. The Department of Intellectual Property's examination process differs accordingly: a petty patent only goes through a formality check and a preliminary novelty check, not the substantive examination required for an invention patent.
Inventions That Cannot Be Registered as a Petty Patent
Section 9 of the Patent Act B.E. 2522 lists categories that cannot be patented, and this applies equally to petty patents, no matter how novel or industrially applicable the invention otherwise is:
- Naturally occurring microorganisms, animals, plants, or extracts from animals or plants
- Scientific and mathematical rules and theories
- Data processing systems for computer operation (computer programs)
- Methods of diagnosis, treatment, or cure of human or animal disease
- Inventions contrary to public order, morality, health, or welfare
This exclusion list is a separate issue from the inventive-step exemption described above - a petty patent doesn't need an inventive step, but it must still avoid every category excluded under Section 9, exactly like an invention patent.
Examples of Inventions Suited to a Petty Patent
A petty patent suits mechanical improvements, material substitutions, or usability tweaks to something that already exists - for example, improving a tool or device's mechanism to make it easier to use, redesigning packaging structure for better usability, or modifying a household appliance's components to be more durable or energy-efficient. What these examples have in common is that they build on something that already exists, rather than inventing something entirely new from scratch. This makes petty patents well suited to SMEs with short product cycles that need protection faster than waiting years for an invention patent to be granted.
What to Check Before You File
Because the Department of Intellectual Property only conducts a preliminary examination for petty patents - not the in-depth novelty check used for invention patents - a registered petty patent can still be challenged and re-examined for novelty later if a dispute arises. Before filing, it's always worth running a novelty search yourself or having a patent agent do it for you, to reduce the risk of the petty patent being challenged down the road.
FAQ
How do the criteria differ between a petty patent and an invention patent?
Both require novelty and industrial applicability. An invention patent additionally requires an "inventive step" - the invention must not be something a person ordinarily skilled in the field could easily come up with. A petty patent doesn't need to meet that bar, so it covers a wider range of inventions and is easier to register.
What happens during examination if an invention falls under one of the legal exclusions?
The Department of Intellectual Property will refuse the application or issue an Office Action asking the applicant to clarify or amend it. If the exclusion can't be resolved, the application is refused. The applicant has the right to appeal the order through the legally prescribed process.