Lapsed Sep 10, 2025 on the fee record · Medium confidence
20-year base term ended Oct 16, 2025
Why Medium: A parent in the chain could not be resolved.
Third maintenance fee unpaid; grace period ended.
Held by BT Wearables LLC
Filed Dec 28, 2011 as application 13/338,269 · Granted Sep 10, 2013
Base term, 20 years from filing, plus 50 days of patent term adjustment (USPTO delay)
Today
Lapsed Sep 10, 2025
2005
2026
Clock starts
Oct 16, 2005
Oct 16, 2005
No longer in force
Sep 10, 2025
Sep 10, 2025
Granted
Sep 10, 2013
Sep 10, 2013
Term would have run to
Dec 5, 2025
Dec 5, 2025
base term
patent term adjustment
after the term ends
fee events
Updated Nov 14, 2026 · includes USPTO assignment & status data published Nov 14, 2026 and grant & fee data published Nov 10, 2026 (weekly) · how we know
50
Days of term adjustment
Read from the USPTO patent term adjustment record, not recalculated here.
None
Terminal disclaimer
No disclaimer on this record.
2 of 3
Maintenance fees paid
Three maintenance fees fall due, at 3.5, 7.5 and 11.5 years from grant. This counts the ones the record shows paid.
26
Family applications on record here
Applications sharing this one's continuity chain whose file history this site holds. The family may have others.
Its term would have run to Dec 5, 2025: its 20-year base term plus 50 days of term adjustment for prosecution delay. Confidence: Medium. from the record
How we calculated this date
One row per rule, each showing its own input and what it did to the date. A step we could not verify says so instead of resolving itself.
| Step | Input | Date after this step | Confidence |
|---|---|---|---|
| Base term, 20 years from filing | Clock starts Oct 16, 2005, when application 11/252,279, the earliest non-provisional in its chain, was filed (this one was filed Dec 28, 2011); a parent in its chain could not be resolved (the next row) | Oct 16, 2025 | High confidence |
| Continuity chain | A parent in the chain could not be resolved | dated from this application's own claim | Medium confidence |
| Patent term adjustment | +50 days, USPTO patent term adjustment record | Dec 5, 2025 | High confidence |
| Terminal disclaimer cap | None on record | no cap applied | High confidence |
| Patent term extension | None on file | no change | High confidence |
| Fee events | 2 of 3 maintenance fees paid | lapsed Sep 10, 2025 | High confidence |
| Computed term end | The steps above, in order | Sep 10, 2025 | Medium confidence |
This family
| Application 90/016,611 | Pending not computed | not computed |
| US 7,420,472 | Lapsed on the fee record Sep 2020 | Sep 2020 |
| US 7,733,224 | In force Oct 2027 | Oct 2027 |
| US 8,647,268 | Lapsed on the fee record Feb 2022 | Feb 2022 |
| US 8,525,673 | Lapsed on the fee record Sep 2025 | Sep 2025 |
| US 8,680,991 | In force no later than Jun 2027 | no later than Jun 2027 |
| US 8,531,291 | this patent Sep 2025 | Sep 2025 |
| US 8,461,988 | Term ended no later than Nov 2025 | no later than Nov 2025 |
8 of 26 applications in this family shown, earliest filings first. The applications whose file history this site holds. The family may have others.
Assignments
Assignment documents as recorded at the USPTO, oldest first, with the reel and frame each was recorded at. A recorded assignment is a filed document, not a statement of current ownership, and the absence of a later one is not evidence that the last one still stands.
| Recorded | Assignor | Assignee | Conveyance |
|---|---|---|---|
| May 28, 2015 Reel 35734, frame 53 | Tran, Bao | Empire IP LLC | Assignment of Assignor's Interest |
| Dec 18, 2015 Reel 37332, frame 414 | Empire IP LLC | West 74TH Street, Series 75 of Allied Security Trust I | Assignment of Assignor's Interest |
| Apr 21, 2016 Reel 38337, frame 970 | West 74TH Street, Series 75 of Allied Security Trust I | Koninklijke Philips N.V. | Assignment of Assignor's Interest |
| Apr 26, 2023 Reel 63452, frame 334 | Empire IP LLC | BT Wearables LLC | Assignment of Assignor's Interest |
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.
Free plan: 3 watched companies. Pro: unlimited.
Alerts on its grants, lapses and transfers.
What's changing
Note
The 50 days of patent term adjustment (USPTO delay) are read from the USPTO record, not recalculated by us
Citations
526
later US patents cite this one
That is top 1% of utility patents granted in 2013 in our data, the only group it is compared against.
How we rank
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
Computed patent terms end on the dates shown. Related patents and pending applications may cover overlapping subject matter.