Filing activity in this dataset concentrates around a Chinese national glassmaking group and its regional subsidiaries, which together account for the strongest co-assignee relationships in the data. Established Western and Japanese glassmakers such as those historically active in tin-bath and float process patents remain present in the record but show markedly lower recent-year filing activity. Anyone assessing freedom-to-operate should treat the Chinese subsidiary network as the most active current filer rather than assuming legacy Western players still lead.

Filings peaked at 74 in 2019 and have fallen since, down to single digits in the most recent partial year, which lags due to normal 18-month publication delay. This pattern is more consistent with a maturing claim space — where core tin-bath, forming and annealing mechanics are already heavily patented — than with a market losing commercial interest in float glass. Filing decline in a densely claimed area typically signals that new entrants face a crowded prior-art landscape, not that the underlying manufacturing process is being abandoned.

C03B, the IPC subclass covering glass manufacture and shaping, appears in 1,115 of the 1,177 records in this dataset — essentially the entire corpus. C03C, glass and enamel compositions, is a distant second at 268 records. Adjacent areas like layered products, coatings, catalytic processes and material testing carry far fewer filings, marking them as comparatively open ground relative to the core forming and shaping claims.

US10753883B2, assigned to Guardian Glass, LLC, covers detecting inclusions such as nickel-sulfide defects in float glass by directing intense visible light at the glass and using thermal imaging to spot temperature differences between an inclusion and the surrounding material, specifically during or after the tin-bath forming and annealing lehr cooling stages. It does not block inclusion detection generally — it is specific to this optical/thermal detection method at this stage of the process. Alternative detection approaches, such as different imaging wavelengths or detection timed to a different process stage, would sit outside its literal claim scope but should be checked individually against the full claim set.

The thinner IPC classes relative to the dominant C03B forming and shaping claims — including B32B laminates, C23C coatings, B01J catalytic processes and G01N testing — carry noticeably fewer filings and represent comparatively under-claimed ground. Specific candidates include real-time nickel-sulfide inclusion imaging methods, melting energy recovery from furnace exhaust, photocatalytic self-cleaning coatings, and thickness uniformity control for thin or ultra-thin float glass. These areas sit adjacent to the heavily claimed core process rather than inside it, making them more viable starting points for new filings.