One assignee leads clearly with 123 of the 842 records in scope, more than double the fifth-placed filer’s 42. The leading five assignees together hold 365 records, 43.3% of the field, and the leading ten hold 477, or 56.7%. Beyond that group filing volume drops into a long tail across the remaining ranked assignees, so a freedom-to-operate review should prioritise the concentrated top tier first.

Filings rose from 8 in 2017 to a peak of 47 in 2022, then fell to 19 by 2024, a 59% decline from the 2021 level of 46. That looks like a pullback from peak activity, but publication lags filing by roughly 18 months, so the 2025-2026 figures in the underlying data are still incomplete and should not yet be read as confirming a continued slowdown. A clearer read will only be possible once those years finish publishing.

H01J, covering electron and discharge tubes, appears in 26.8% of the 842 records, and C23C, covering coating and surface deposition, appears in 22.2% — both ahead of the core non-positive-displacement pump class F04D at 17.9%. This shows the field is defined as much by integrating pumps into semiconductor and coating process chambers as by pump mechanism design itself. Records frequently carry more than one class, so these percentages overlap rather than summing to 100%.