Low-E Glass Coating Patents: Who Leads, Where the Gaps Are 2026
- Five companies hold 49.2% of the field. 1,156 of 2,349 records in scope sit with the top five assignees alone — a narrow group controls close to half of everything filed.
- Filing has pulled back from its 2019 peak. The peak year so far is 2019 at 97 filings; from 2021 (69) to 2024 (31), filings fell 55% over that three-year span.
- Silver-stack claims dominate; adjacent branches thin out fast. C03C glass compositions cover 61.7% of records, but vehicle glazing (B60J, 3.4%) and coating process claims (B05D, 3.1%) are comparatively open.
Filing growth compares 2021 (69 records) with 2024 (31) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 2,349 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Low-emissivity and solar control glass coatings sit at the intersection of thin-film deposition and architectural or automotive glazing. The claims in scope here center on magnetron-sputtered silver stacks — dielectric, nucleation, silver and barrier layers built to hit a target emissivity value and solar heat gain figure while surviving tempering or heat-strengthening. Coating durability and tempering compatibility are recurring claim elements because a stack that performs optically but delaminates or hazes under heat treatment is commercially useless.
The 2,349 records in scope span 2015 through the 2026 data cut-off, filed largely through the United States, EPO, WIPO/PCT and Canadian offices, with Australia and Austria also carrying meaningful volume. Because publication lags filing by roughly 18 months, the 2025-2026 figures in any trend chart are still filling in and should not be read as a slowdown.
Filing trend and technology composition
Two views of the same 2,349-record corpus: how filing activity has moved year over year, and which IPC subclasses carry the claim density.
Filing trend: a 2019 peak, then a real pullback
Filings ran from 21 in 2017 to a peak of 97 in 2019, then declined; the 2021-to-2024 window alone shows a 55% drop, from 69 down to 31. Treat 2025 and 2026 as incomplete rather than as evidence of further decline — publication lag means those years are still being populated.
Where the claims concentrate
C03C (glass and enamel compositions) touches 61.7% of the 2,349 records, with B32B (layered products) at 38.2% and C23C (coating and surface deposition) at 26.1% close behind — the core silver-stack chemistry is heavily claimed. E06B (windows, doors and shutters) at 18.4% and G02F (optical control and modulation) at 8.9% show where fenestration-system and switchable-glazing integration claims sit. B60J (vehicle glazing, 3.4%) and B05D (coating processes, 3.1%) carry far fewer records relative to the total.
Shares are the percentage of the 2,349 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Low-E and Solar Control Glass Coatings with Eureka
This page is one run against one query. Ask Eureka your own question about low-e and solar control glass coatings and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this field
Low-E coating with low solar heat gain coefficient, enhanced durability and tempering tolerance
The invention provides low-emissivity stacks characterized by a low solar heat gain coefficient (SHGC), enhanced aesthetics, mechanical and chemical durability, and a tolerance for tempering or heat strengthening. The coatings comprise, in order outward from the substrate, a first dielectric layer, a first nucleation layer, a first Ag layer, a first barrier layer, a second dielectric layer, a second nucleation layer, a second Ag layer, a second barrier layer, a third dielectric layer, and optionally a topcoat layer.Filed by Cardinal CG Company, published 2009-05-28 as US20090136765A1.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6576349B2 | Heat treatable low-E coated articles and methods of making same | 579 |
| 2 | US4898789A | Low emissivity film for automotive heat load reduction | 568 |
| 3 | US5821001A | Coated articles | 518 |
| 4 | US4806220A | Method of making low emissivity film for high temperature processing | 510 |
| 5 | US4898790A | Low emissivity film for high temperature processing | 474 |
| 6 | US4610771A | Sputtered films of metal alloy oxides and method of preparation thereof | 455 |
| 7 | US20100315693A1 | Variable transmittance optical filter and uses thereof | 348 |
| 8 | US4861669A | Sputtered titanium oxynitride films | 331 |
| 9 | US5059295A | Method of making low emissivity window | 324 |
| 10 | US4716086A | Protective overcoat for low emissivity coated article | 307 |
Citation counts inside a searched corpus favor older filings by construction — read them as a signal of influence on later filers, not as a measure of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Reading the concentration, trend and citation data together points to where claim space is occupied and where it is not.
The leaderboard is short and dense
The leader alone holds 406 records, and the top five combined account for 1,156 of the 2,349 records in scope — 49.2% of the field. The top ten push that to 68.1%. A new entrant filing core silver-stack claims is filing into ground already dense with prior art from a handful of glass manufacturers.
Volume has cooled from its 2019 high
Filings peaked at 97 in 2019 and have declined since; the 2021-2024 window shows a 55% drop. That does not mean the technology is exhausted — it more likely reflects that the dominant silver-stack architecture is well-claimed and later filers are working narrower variations.
Core chemistry is the busiest class
C03C alone touches 61.7% of all records, with B32B and C23C close behind. That density is about occupied claim space, not technology maturity — durability and tempering-compatibility claims keep generating filings even where the base stack architecture is decades old.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to low-e and solar control glass coatings, with the prior art for and against each one.
Who holds the field, and where momentum has gone quiet
A small set of glass manufacturers built the current claim landscape through the mid-2010s peak. Recent-year filing activity from the named leaders has largely gone flat.
The top assignee holds nearly a fifth of the field
At 406 records, the leading assignee sits well ahead of fifth place at 169 and tenth place at 68 — a steep drop-off rather than a gradual one, typical of a field anchored by a founding architecture patent family.
Corporate structure shows up as co-assignee pairs
The strongest co-assignee pairing spans 118 shared records, consistent with parent-subsidiary filing across group entities rather than genuine external collaboration. Ten such pairs exist in total across the corpus.
The named leaders show no latest-year activity
Every one of the top-ranked assignees shows zero filings in the latest year in this dataset, with one showing a -100% year-on-year change. Given the 18-month publication lag, this reads as a reporting gap rather than a withdrawal from the space.
| Assignee | Recent year | YoY |
|---|---|---|
| Guardian Industries Corp | 0 | — |
| PPG Industries Ohio, Inc. | 0 | — |
| Centre Luxembourgeois de Recherches pour le Verre et la Ceramique SA (C.R.V.C.) | 0 | — |
| Cardinal CG Company | 0 | — |
| AGC Glass Europe SA | 0 | -100% |
| PPG Industries, Inc. | 0 | — |
| AGC Flat Glass North America, Inc. | 0 | — |
| Vitro Flat Glass LLC | 0 | -100% |
Where to take this analysis
The figures here establish the shape of the field. Turning that into a filing or freedom-to-operate decision means going claim by claim.
Map claim scope against your own stack design
Concentration figures show who holds volume, not which specific claim elements block a given layer sequence. A claim-level comparison against the leading families is the next step before committing to a filing direction.
Explore claims in EurekaTrack the under-claimed branches as they mature
Vehicle glazing and coating-process claims currently carry a small share of records. Monitoring those branches for new entrants over the next few publication cycles will show whether that white space is closing.
Set up monitoring in EurekaCommon questions on low-E and solar control glass coating patents
The field is concentrated: the leading assignee holds 406 of the 2,349 records in scope, and the top five combined account for 1,156 records, or 49.2% of the total. That concentration reflects a small group of established flat-glass manufacturers who built out the core silver-stack architecture over the past decade. A new entrant should expect to compete against dense prior art from these firms specifically in the dielectric-nucleation-silver-barrier layer sequence, rather than a fragmented field of small players.
No — filing peaked in 2019 at 97 records and has declined since, with the 2021-2024 window showing a 55% drop from 69 to 31 filings. That said, figures for 2025 and 2026 are still incomplete because publication typically lags actual filing by around 18 months, so the most recent years understate real activity. The honest read is a field that has cooled from its peak, not one that has stopped moving.
C03C, the glass and enamel compositions class, touches 61.7% of the 2,349 records in scope, making it the busiest single class. B32B (layered products and laminates) follows at 38.2% and C23C (coating and surface deposition) at 26.1%, which together describe the physical silver-stack build. Because a single record can carry multiple IPC classes, these shares add up to more than 100% — they describe claim density per class, not a breakdown of the whole field.
Relative to the core glass-composition and layered-product classes, vehicle glazing integration (B60J, 3.4% of records) and coating process claims (B05D, 3.1%) carry noticeably less filing density. Electrochromic and switchable modulation claims under G02F sit at 8.9%, also below the core classes. These lower shares do not guarantee an easy path to a grant, but they indicate branches where the claim space is comparatively less occupied than the dominant silver-stack chemistry.
US20090136765A1, filed by Cardinal CG Company and published in 2009, claims a low-emissivity coating stack built outward from the substrate as a first dielectric layer, first nucleation layer, first silver layer, first barrier layer, second dielectric layer, second nucleation layer, second silver layer, second barrier layer, third dielectric layer, and an optional topcoat. Its significance is combining a specified low solar heat gain coefficient with tempering or heat-strengthening tolerance and chemical and mechanical durability in one layer sequence. Anyone designing a comparable dual-silver stack for the same performance profile needs to check this filing's specific layer count and material claims for overlap.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
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Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.