Which is the competent authority for invention patent applications in Thailand?

via Paris Convention : 6 months from earliest priority date.

DIP conducts substantive examination of design patent applications, and only examines whether the conditions of novelty and industrial applicability are met.

no

20 years

DIP only conducts formality examination for utility models, and the documents can be authorized if they meet the formality examination standards. If litigation or evaluation of the stability of utility model Claim is required, the applicant may submit a request for substantive examination within one year after the granted announcement.

• Authorization Fee: None
• Annuity: The applicant should pay the first annual fee at the beginning of the 5th year from the application date. If it is authorized at the beginning of the 5th year, it must be paid within 60 days from the date of granted. If the annual fee is overdue, it can be paid within 120 days of the overdue period. The annual fee can be paid for multiple years at one time.

Reinstatement of priority on grounds of "due care" accepted.

yes. A patent applicant can convert the patent type from a petty patent (utility model) to an invention before the patent application is granted. The converted patent application has the filing date of the original patent application.

• via Paris Convention : 12 months from earliest priority date.
• via Nationalization of PCT : 30 months from the earliest priority date.