Filing in this dataset is concentrated at the top: the leading assignee alone accounts for 6,010 of the 14,878 records in scope, and the top 5 assignees combined hold 52.0% of all records. The leader's portfolio is weighted heavily toward lithographic metrology and substrate-measurement technology rather than plant-floor SCADA logic in the narrow industrial sense, so readers focused specifically on process-control SCADA should look past the raw ranking to the IPC composition for context. The ranking itself covers 100 companies and is not a top-50 or top-100 cutoff — it is the full list the dataset returns.

Filings peaked in 2020 at 896 and fell from 809 in 2021 to 478 in 2024, a 41% drop over that three-year window. That said, publication typically lags filing by around 18 months, so 2025 and 2026 figures in the trend line are still incomplete and should not be read as evidence the field itself is winding down. The safest read is that filing activity cooled through the early 2020s relative to its 2020 peak, based on the years for which the data is complete.

Photolithography and photomechanics (G03F) is the single largest classification, touching 36.3% of the 14,878 records in scope, reflecting how much of this corpus intersects with semiconductor manufacturing metrology rather than generic industrial control. Control and regulating systems (G05B) at 11.1% and electric digital data processing (G06F) at 10.3% are the next largest clusters, followed closely by material analysis and testing (G01N) at 10.0%. Because a single record can carry several IPC classes, these percentages overlap and should not be summed.

Power supply and grid systems (H02J) and optical elements and systems (G02B) show the lowest shares among the major classes covered here, at 5.2% and 4.9% of the 14,878 records respectively, suggesting comparatively less claim density than the dominant photolithography and control-systems clusters. Co-assignee collaboration is also rare across the dataset, with only 10 recorded co-assignee pairs, meaning joint industry-academic filings in adjacent sensing-and-control combinations remain uncommon. Teams looking for open claim space should look specifically at supervisory control tied to grid-state inputs or optical-sensing feedback, rather than at the core metrology or control-loop claims already held by the leading filers.

US20070147232A1, filed by Toshiba and published in 2007, claims a specific redundant supervisory control architecture built from paired controllers, loop interface units, and communication cables wired into a circular loop, with a redundancy-switching method for that topology. It blocks designs that reproduce that specific circular-loop redundancy structure, not redundancy in supervisory control generally, so systems using star, mesh, or software-defined failover approaches sit outside its literal claim scope. Any freedom-to-operate check involving redundant SCADA architectures should treat this record as a reference point for the circular-loop topology specifically, alongside newer filings in the same design space.