Granted Patent
Utility
US 6,584,979 · App. 09/839,669
High efficiency cigarette filters having shaped microcavity fibers impregnated with adsorbent or absorbent materials
Inventors:
Lixin Xue, Kent B. Koller, Qiong Gao
Patented Case
View Patent ↗
Granted: Jul 1, 2003
Filed: Apr 20, 2001
Inventors
Lixin Xue
Kent B. Koller
Qiong Gao
Assignee (at issue)
Philip Morris Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.