The assignee ranking in this dataset covers 100 companies, with the single leader holding 85 records against a fifth-place count of 30 and a tenth-place count of 18. That drop-off shows a genuine leader-plus-pack structure rather than an evenly spread field. The top 5 assignees together account for 24.2% of all 987 records in scope, and the top 10 account for 35.8%, so a meaningful share of the field still sits outside any single dominant filer.

Filing peaked at 21 records in 2020 and has since eased, moving from 5 in 2021 down to 3 in 2024, a -40% change over that span. Counts for 2025 and 2026 look lower still, but publication typically lags actual filing by around 18 months, so those most recent years are understated rather than proof of a real decline. Read the 2021-2024 window as the most reliable recent signal.

Japan's receiving office accounts for 570 of the 987 records in this dataset, far ahead of the United States at 150 and the European Patent Office at 90. The United Kingdom, Canada and Australia each sit in the twenties. Anyone running a clearance search on this topic without a Japanese-language pass is missing the majority of documented activity.

US20160068986A1, filed by Suzuki Motor Corporation, covers a two-step anodizing sequence: a direct-current electrolysis step forming a second anodic oxide film, followed by an AC-DC superimposition electrolysis step forming a first anodic oxide film, then a sealing treatment using a lithium-ion-containing solution on both films. Work that replicates that specific DC-then-AC/DC sequence combined with lithium-ion sealing sits closest to its claims. Processes using a single-step anodizing bath, a different sealing chemistry, or a different electrolysis order are the more likely paths around it, though a formal freedom-to-operate opinion should confirm claim scope against the granted claim set rather than the published application.

The technology composition data shows the field concentrated heavily in electroplating and electroforming (C25D, 60.8% of the 987 records), with much thinner coverage in areas like colour consistency measurement, hard-anodizing bath temperature control, and corrosion test hour benchmarking. Those thinner branches are worth a closer look for a first claim, particularly where they combine a specific measurable quality control step with the anodizing bath chemistry. High density in the core electroplating classification means that ground is occupied, not that it is exhausted of value — but new entrants are better served looking at the adjacent, thinner branches first.