Это специфика патентой системы Гонконга, наследие колониального прошлого ))
Смысл термина - зарубежный патент, признаваемый в силу международных или иных обязательств Гонконга.

What is a designated patent office and a designated patent application?
The grant of a standard patent in Hong Kong, China is based on the registration of a patent granted by one of three designated patent offices
◦State Intellectual Property Office, People's Republic of China
◦European Patent Office, in respect of a patent designated the United Kingdom
◦United Kingdom Patent Office.
The standard patent application in Hong Kong, China is made in two stages by filing
◦a request to record the designated patent application, that is the Chinese, EP(UK) or UK published patent application
◦a request for registration and grant in Hong Kong, China of the Chinese, EP(UK) or UK granted patent.