Chemically Strengthened Glass Substrates Patents: Leaders & Trends 2026
- Filings peaked in 2017 at 101 and have declined through the midpoint year, 2022, at 57 — the core compressive-stress and ion-exchange claim space was staked out early and filing activity has been cooling since.
- C03C glass compositions cover 941 of 944 families , but B32B laminate claims (110) and H05K circuit-assembly claims (29) show the technology's reach into cover-glass and device integration.
- United States receiving-office filings (368) outnumber China (120) and Japan (89) combined , signalling where enforcement risk concentrates for anyone shipping strengthened cover glass into that market.
Filing growth compares 2021 (70 records) with 2024 (45) — 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 944 records in scope (CR5), not by the ranked leaders only.
What this patent set covers
Chemically strengthened glass substrates rely on ion exchange — typically a molten potassium nitrate bath swapping smaller sodium ions in the glass surface for larger potassium ions — to build a compressive stress layer that resists cracking and improves drop resistance. This dataset tracks 944 patent families filed between 2015 and 2026 across the core chemistry (aluminosilicate formulations), the process (bath composition, dwell time, depth of layer), and the downstream product claims that wrap strengthened sheets into cover plates, laminates and display assemblies.
The IPC spread shows a technology anchored in glass composition and manufacture (C03C, C03B) with a meaningful secondary cluster in layered products (B32B) — the laminate and cover-plate claims that turn a strengthened sheet into a shippable component. Smaller clusters in printed circuits, optics and displays mark where strengthened glass meets device integration rather than glass chemistry itself.
Filing trend and technology composition
Two views of the same 944-family dataset: how filing volume has moved year over year, and how those filings split across the IPC subclasses that define the technology's footprint.
Filing trend, 2015-2026
Filings rose to a peak of 101 in 2017, held near the 2022 midpoint value of 57, and have tapered toward the 2026 data cut-off. Because publication lags filing by roughly 18 months, the last one to two years understate true filing activity — but the multi-year decline from the 2017 peak is a real trend, not an artefact of the cut-off.
IPC subclass composition
C03C dominates at 941 of 944 records, confirming this is fundamentally a glass-composition patent set. B32B (110) and H05K (29) mark the laminate and electronics-integration edges where strengthened substrates get claimed as part of a larger assembly rather than as glass alone.
Shares are the percentage of the 944 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Chemically Strengthened Glass Substrates with Eureka
This page is one run against one query. Ask Eureka your own question about chemically strengthened glass substrates and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records and a representative recent grant
US11753334B2 — Ion exchange processes and chemically strengthened glass substrates resulting therefrom
A method of performing ion exchange of a thin, flexible glass substrate having an average thickness equal to or less than about 0.3 mm to chemically strengthen the glass substrate is disclosed. The chemically strengthened glass substrate comprises a first compressive stress layer having a first depth of layer, and a second compressive stress layer having a second depth of layer, the first and second stress layers being separated by a layer of tensile stress. A laminated article comprising the chemically strengthened glass substrate is also described.Granted to Corning Incorporated, September 2023 — a dual-compressive-layer architecture aimed squarely at thin, flexible substrates rather than rigid cover plates.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US7666511B2 | Down-drawable, chemically strengthened glass for cover plate | 565 |
| 2 | US20080286548A1 | Down-drawable, chemically strengthened glass for cover plate | 379 |
| 3 | US20150259244A1 | Strengthened glass with deep depth of compression | 245 |
| 4 | US20120196071A1 | Strengthened glass substrate sheets and methods for fabricating glass panels from glass substrate sheets | 243 |
| 5 | US20120034435A1 | Coated, antimicrobial, chemically strengthened glass and method of making | 235 |
| 6 | US20120135195A1 | Methods for separating glass articles from strengthened glass substrate sheets | 215 |
| 7 | US20150239775A1 | Strengthened glass with deep depth of compression | 200 |
| 8 | WO2008143999A1 | Down-drawable, chemically strengthened glass for cover plate | 179 |
| 9 | US20170305786A1 | Glass-based articles including a metal oxide concentration gradient | 165 |
| 10 | US20150368153A1 | Strengthened glass with deep depth of compression | 136 |
Citation counts favour older records simply because they have had more time to accumulate citations within the searched corpus — treat them as a signal of influence on the field, not as a ranking of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three read-throughs from the trend, the citation table and the jurisdiction split that matter more than the raw counts on their own.
The core claim space was staked out early
Filings peaked in 2017 and have declined toward the 2026 cut-off, with the 2022 midpoint at 57 marking the point the decline became visible. New entrants now file into a compressive-stress and depth-of-layer claim space that has been worked for close to a decade.
Influence sits with early down-drawable cover glass patents
The most-cited records in this set are down-drawable, chemically strengthened cover-plate patents from the late 2000s and early 2010s. Their citation counts reflect years of accumulation inside a searched corpus, not that today's filers are still building directly on them.
Enforcement exposure concentrates in the US
United States filings outnumber China, WIPO/PCT and Japan individually by a wide margin. Anyone shipping strengthened cover glass or laminated assemblies into the US market is filing into the most heavily claimed jurisdiction in this dataset.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to chemically strengthened glass substrates, with the prior art for and against each one.
Who holds the ground and where momentum has gone
Recent-year filing momentum across the named assignees is flat to negative across the board, consistent with the overall filing decline — the question for a new entrant is less who is currently active and more where the accumulated claim density sits.
Chongqing Xinjing Special Glass
Chongqing Xinjing is the only assignee in the momentum table still filing in the latest year, albeit down sharply from the prior year. Its co-filing pair with Huawei (11 shared families) points to device-integration claims layered on top of substrate chemistry.
Corning
Corning holds several of the most-cited records in the dataset, including the representative US11753334B2 grant, but shows no filings in the latest tracked year. Its portfolio anchors the down-drawable and dual-compressive-layer approaches other filers now design around.
AGC and peers
AGC (including its European glass affiliate, with 13 shared families) and other Japanese glassmakers show no latest-year filings in this set, consistent with the sector-wide decline from the 2017 peak rather than any single company's retreat.
| Assignee | Recent year | YoY |
|---|---|---|
| Chongqing Xinjing Special Glass Co., Ltd. | 1 | -83% |
| Asahi Glass Co., Ltd. (AGC) | 0 | -100% |
| Corning Incorporated | 0 | -100% |
| Central Glass Co., Ltd. | 0 | — |
| Nippon Sheet Glass Co., Ltd. | 0 | — |
| AGC Glass Europe | 0 | — |
| Huawei Technologies Co., Ltd. | 0 | -100% |
| Nippon Electric Glass Co., Ltd. | 0 | — |
Where to take this next
The trend and rankings on this page are a starting point for freedom-to-operate and whitespace work, not a substitute for it.
Map the citation network around the top-cited families
US7666511B2 and its peers anchor most of the down-drawable cover-glass claim space. A citation map from those records will surface which later filings design around them and which infringe.
Explore citation mapping in EurekaRun a claim-level comparison on depth-of-layer and dual-stress architectures
The gap between rigid cover-plate claims and thin, flexible dual-compressive-layer claims like US11753334B2 is where new filings are landing. A claim chart against that family clarifies how much room remains.
Build a claim chart in EurekaCommon questions about chemically strengthened glass patents
The most-cited records in this space trace back to early down-drawable cover-glass patents such as US7666511B2 and US20080286548A1, both tied to Corning's cover-plate work. Corning also holds more recent grants such as US11753334B2, covering dual-compressive-layer architectures for thin, flexible substrates. Japanese glassmakers including AGC, Nippon Electric Glass and Nippon Sheet Glass, along with Chinese specialists such as Chongqing Xinjing Special Glass, also hold substantial filing positions, though the dataset shows filing momentum across all of these assignees has slowed sharply in the most recent tracked year.
Filings peaked at 101 in 2017 and had fallen to 57 by the 2022 midpoint, continuing to decline toward the 2026 cut-off in this dataset. This pattern typically reflects a claim space that was densely staked out early — the core ion-exchange process and compressive-stress-layer claims — leaving less room for entirely new foundational filings. It does not mean the underlying technology or market has slowed; cover-glass demand for mobile devices and displays has continued to grow even as core-chemistry filing has cooled.
Depth of layer describes how far the compressive stress created by ion exchange extends beneath the glass surface, and it is one of the most commonly claimed parameters in this dataset alongside compressive stress magnitude. Deeper compressive layers generally improve drop and scratch resistance but can affect strength trade-offs elsewhere in the glass. Because it is a measurable, tunable process parameter, depth of layer shows up repeatedly in claim language, including in the representative record on this page, which claims two distinct compressive stress layers with separate depths.
Yes, though it sits at the edges rather than in the core chemistry. The IPC composition shows heavy concentration in C03C glass compositions (941 of 944 records), with thinner activity in adjacent areas like optical modulation (G02F, 27 records) and printed circuit integration (H05K, 29 records). Sub-areas such as asymmetric dual-compression profiles, bath chemistries beyond potassium nitrate, and strengthened substrates under 0.3mm for foldable devices show filing activity but not the density seen in core cover-plate claims, making them worth a closer freedom-to-operate look.
US11753334B2, granted to Corning in September 2023, claims an ion-exchange process producing two separate compressive stress layers separated by a tensile layer, specifically for thin, flexible substrates at or below 0.3mm thickness. Anyone developing thin flexible strengthened glass with a dual-compressive-stress profile needs to check their process and resulting stress architecture against this claim scope. Alternatives that use a single compressive layer, a different thickness regime, or a materially different stress-layer separation mechanism may fall outside its claims, but that requires a proper claim chart rather than a reading of the abstract alone.
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