Modulated resistance heater infrared radiation source
US 6,875,991 Term endedTerm ended no later than Apr 5, 2022 · From the USPTO record
20-year base term ended Apr 5, 2022
Jan 29, 1973
Apr 5, 2022
Apr 5, 2005
How we calculated this date
| Step | Input | Date after this step | Confidence |
|---|---|---|---|
| Base term, the 1995 transition rule | Granted Apr 5, 2005 + 17 years, or clock starts Jan 29, 1973 + 20 years, whichever is later | Apr 5, 2022 | High confidence |
| Continuity chain | Every parent in the chain resolved | no change | High confidence |
| Patent term adjustment | None on file | no change | High confidence |
| Terminal disclaimer cap | Disclaimer on file (approved), reference document not resolved | no cap applied, and none guessed | Medium confidence |
| Patent term extension | None on file | no change | High confidence |
| Fee events | No fee events in USPTO's record of this patent. A gap in the record, not evidence of lapse | term ended | Medium confidence |
| Computed term end | The steps above, in order | no later than Apr 5, 2022 | From the USPTO record |
Sources
Google Patents · The patent document at USPTO · Assignment records at USPTO
USPTO account required: This application in Patent Center · USPTO's maintenance fee lookup
Maintenance fee events come from USPTO's own fee records. Its fee lookup asks for the patent number and the application number.
Not on this page: the patent's family, its recorded assignments and its citation count. USPTO's assignment records, linked above, list every recorded assignment.
Every date shows its work: the base term, any term adjustment or extension, any disclaimer cap, and the maintenance fee record, each with a confidence tier. How this record was built
This computed term ends no later than the date shown; an unresolved terminal disclaimer may end it earlier. Related patents and pending applications may cover overlapping subject matter.