The leading assignee in this dataset holds 55 records, with the fifth-ranked assignee at 36 and the tenth at 32 — a gradual slope rather than a sharp drop-off. The top 5 assignees combined account for only 5.3% of all 4,129 records in scope, and the top 10 for 9.4%, so no single company controls a dominant share of filings. This is a fragmented field with a long tail of smaller filers rather than one led by a clear gatekeeper.

Filing peaked in 2020 at 256 records and declined to 151 by 2024, a 21% drop across that complete-year window. Figures for 2025 and 2026 look lower still, but publication typically lags actual filing by around 18 months, so those years are undercounted and should not be read as a sign the field is dying. The honest read is a field past its filing peak but still producing well over a hundred records a year as of the last complete year measured.

Temperature measurement (IPC class G01K) is by far the densest, covering 28.2% of all 4,129 records in scope. Diagnosis/surgery (A61B) and electric heating circuits (H05B) each account for 6.5%, with flow measurement, material analysis, non-electric control and electric/magnetic measurement classes each in the 4-5% range. Because records can carry multiple IPC classes, these percentages overlap and sum to more than 100%; they describe density, not mutually exclusive segments.

US20210072095A1 claims a chip wiring layer temperature sensing circuit that uses a metal interconnection structure connected to a pulse delay detection module, converting delay data from a high-speed clock pulse into a temperature reading via a transition module. Its scope is specific to on-chip wiring-layer temperature detection using pulse-delay conversion, filed by Zhejiang Johar Technology and published in 2021. It would not block cavity-pressure sensing, external thermocouple-based mold instrumentation, or correlation/retrofit methods that do not rely on this pulse-delay conversion architecture, though anyone building silicon-embedded temperature sensing using delay-based conversion should review it closely.

The evidence points to several under-claimed branches relative to the dense G01K core: connector survival under repeated thermal cycling, closed-loop switchover logic for retrofitting existing tooling, cavity-pressure-to-defect correlation modelling, and wiring harness routing within mold inserts. These sit adjacent to heavily claimed temperature-sensing hardware but show comparatively thin density in this dataset's technology composition. A first claim in these areas would likely combine a specific sensor-signal correlation method with a named failure mode or retrofit constraint, rather than claiming the sensor hardware itself.

Not much on balance: only 10 co-assignee pairs appear across the ranked assignees, and most filings in this dataset are single-assignee. One aerospace pairing stands out with 41 shared records, well ahead of the next pairs at single digits. For most companies entering this space, joint filing arrangements are the exception rather than the norm, so competitive assessment should focus on individual assignee portfolios rather than collaboration networks.