Within three years from the filing date (priority date).
The time limit for an invention patent applicant to request substantive examination is three years from the filing date (priority date). If a request for substantive examination is not made within this period, the application will be deemed to have been withdrawn. If the substantive examination request has not been submitted and the fee has not been paid three months before the expiration of the substantive examination request period, the official will issue a notice informing the applicant that the substantive examination period is about to expire; if the substantive examination request is not processed within the expiration date, the application will be deemed to have been withdrawn.