In this landscape, it is a filing that combines gas sensor, gas detection sensor or chemiresistive gas sensor language with claims specifically addressing long-term stability, baseline drift suppression or poisoning resistance. That excludes general gas-sensing patents that only claim detection accuracy or sensitivity without addressing how the sensor holds up over time or against contaminants. The 1,611 families in this dataset were filtered on that combination, filed between 2015 and mid-2026.

Robert Bosch, Honeywell, General Electric, Sensirion, NGK Insulators and Draeger Safety all appear in the historical assignee ranking, but recent-year activity has thinned across nearly all of them. Several, including Sensirion and NGK Insulators, show zero filings in the latest year despite a strong historical presence, while Bosch, GE and Honeywell each show only a single filing. That pattern suggests no single company currently dominates new filing activity, even though a handful of firms built the foundational portfolio.

No — the data shows a plateau rather than continued growth. Filings rose from 44 in 2017 to a peak of 109 in 2025, but the 2022 midpoint of 92 was already close to that eventual peak, meaning most of the growth happened years before the peak year. The partial 2026 figure of 20 looks like a steep drop but is largely a publication-lag artefact, since granted and published filings typically trail the actual filing date by around 18 months.

Material analysis and testing (G01N) dominates, accounting for 1,211 of the 1,611 records in this dataset — close to three-quarters. Semiconductor devices, nanotechnology applications, batteries and cells, other metal compounds, diagnosis and surgery, separation processes and catalysis each hold much smaller shares, roughly 50 to 90 records apiece. That concentration means most durability innovation is still being claimed as a sensing-element problem rather than through adjacent materials, filtration or systems approaches.

The subclasses furthest from G01N's density are the more promising areas to search first: separation processes and filtration (B01D, 54 records), catalysis (B01J, 50), and battery-integrated sensing (H01M, 79) are all thin relative to the dominant G01N cluster. A first claim built around catalyst poisoning-resistant coatings or membrane-based selective filtration for gas sensors is likely to encounter less prior art than one filed directly against G01N's core drift-correction and coating claims.

This Robert Bosch filing claims a gas sensor element with a gamma alumina or alumina coating applied by plasma spraying, designed to withstand thermal shock at temperatures above roughly 500 to 600 degrees Celsius. It protects both the coated sensor element itself and the plasma-spray method of applying that coating for thermal shock resistance. Anyone designing a high-temperature gas sensor that relies on an alumina-family thermal barrier coating applied by plasma spraying should review this filing's specific claim scope and priority date before finalising a design.