专利号不仅仅是一个数字编码,从专利号上是可以观察到许多特征的。 U.S. Application Series Codes Code: Filing Dates: 02 Filed prior to January 1, 1948 03 January 1, 1948 through December 31, 1959 04 January 1, 1960 through December 31, 1969 05 January 1, 1970 through December 31, 1978 06 January ...