Lapsed Sep 10, 2025 on the fee record · Medium confidence
20-year base term ended Apr 1, 2025
Why Medium: A terminal disclaimer is on file (approved) with no resolved reference, so the term may end earlier.
Third maintenance fee unpaid; grace period ended.
Filed Dec 8, 2009 as application 12/632,949 · Granted Sep 10, 2013
Base term, 20 years from filing, plus 499 days of patent term adjustment (USPTO delay)
Today
Lapsed Sep 10, 2025
2005
2026
Clock starts
Apr 1, 2005
Apr 1, 2005
No longer in force
Sep 10, 2025
Sep 10, 2025
Granted
Sep 10, 2013
Sep 10, 2013
Term would have run to
Aug 13, 2026
Aug 13, 2026
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
499
Days of term adjustment
Read from the USPTO patent term adjustment record, not recalculated here.
Unresolved
Terminal disclaimer
On file, reference document not resolved, so the date above is an upper bound. We do not guess the cap.
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.
2
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 Aug 13, 2026: its 20-year base term plus 499 days of term adjustment for prosecution delay. A terminal disclaimer is on file with no resolved reference, so no cap is applied and none is guessed. 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 Apr 1, 2005, when application 11/097,448, the earliest non-provisional in its chain, was filed (this one was filed Dec 8, 2009) | Apr 1, 2025 | High confidence |
| Continuity chain | Every parent in the chain resolved | no change | High confidence |
| Patent term adjustment | +499 days, USPTO patent term adjustment record | Aug 13, 2026 | 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 | 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
| US 7,629,989 | In force Nov 2027 | Nov 2027 |
| US 8,531,494 | this patent Sep 2025 | Sep 2025 |
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 |
|---|---|---|---|
| Mar 21, 2013 Reel 30058, frame 669 | K-NFB Reading Technology, Inc. | K-NFB Holding Technology, Inc. | Change of Name |
| Mar 21, 2013 Reel 30059, frame 351 | K-NFB Holding Technology, Inc. | K-NFB Reading Technology, Inc. | Assignment of Assignor's Interest |
| Dec 30, 2014 Reel 34599, frame 860 | K-nfb Holding Technology, Imc. | Fish & Richardson P.C. | Lien |
| Apr 29, 2015 Reel 35522, frame 289 | K-NFB Reading Technology, Inc. | KNFB Reader, LLC | Assignment of Assignor's Interest |
| May 1, 2015 Reel 35546, frame 143 | KNFB Reader, LLC | Dimensional Stack Assets LLC | License |
| Jan 27, 2016 Reel 37603, frame 342 | Fish & Richardson P.C. | KNFB Reader, LLC | Release and Termination of Liens |
| Jan 6, 2022 Reel 58577, frame 914 | KNFB Reader, LLC | The National Federation of the Blind | 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.
What's changing
Note
A terminal disclaimer is on file and its reference is not resolved. No cap is applied and none is guessed
Note
The 499 days of patent term adjustment (USPTO delay) are read from the USPTO record, not recalculated by us
Open question
A terminal disclaimer is on file (approved) and its reference document is not resolved. A disclaimer would cap the term earlier than Sep 10, 2025. We will not guess the cap.
Citations
9
later US patents cite this one
That is above the median 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.