In Taiwan, an invention for an article or device may be protected by either an invention patent or a utility model patent. The term of an invention patent is 20 years, but substantive examination may take one-and-a-half to three years. Although the term of a utility model patent is 10 years, since substantive examination is not conducted, a utility model patent generally may be obtained within four to six months of filing. Therefore, some applicants employ the strategy of filing invention and utility model patent applications for the same invention on the same day.