Photochromic and Electrochromic Materials Patents: Leaders & Trends 2026
- Filing has already peaked. Grants ran from 9 in 2017 to a high of 33 in 2021, then eased back toward the 2022 midpoint of 23 — a maturing, not a growing, field.
- Rearview mirror claims still anchor the citation graph. The five most-cited records are all electrochromic mirror patents, several sharing the same 'third surface metal reflector' construction, with citation counts running from 466 to 810.
- The named leading assignees show zero filings in the latest year. Momentum has shifted away from the historically dominant players, opening room for newer entrants like Ambilight to stake out claims in ion storage and conducting-polymer layers.
Filing growth compares 2021 (33 records) with 2024 (8) — 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 506 records in scope (CR5), not by the ranked leaders only.
What this dataset covers
This landscape draws on 506 patent families published between 2015 and mid-2026 that claim electrochromic materials, photochromic materials or smart window films, specifically where the claims or description touch switching speed, coloration efficiency, cycling durability, ion storage layers or haze. The IPC scope centres on G02F1 (optical modulation), C09K9 (materials for chromic applications) and E06B9 (window and shading hardware), which keeps the set focused on functional device claims rather than general optics.
Because publication typically lags filing by around 18 months, the 2025 and 2026 counts in the trend chart are undercounts of actual filing activity and should be read as provisional rather than a genuine falloff.
Filing trend and technology composition
Two views of the same 506-family dataset: how filing activity has moved year over year, and how those families split across IPC subclasses.
Filings rose to a 2021 peak, then eased
Annual filings climbed from 9 in 2017 to a peak of 33 in 2021. By the 2022 midpoint, filings had settled to 23, and the trend has flattened since — consistent with a field where core device architectures are established and incremental filing has slowed, allowing for the reporting lag in the most recent years.
G02F and C09K dominate; vehicle and display uses trail
G02F (optical control and modulation) appears in 426 of 506 families and C09K (chromic materials) in 189, confirming that most activity is device- and materials-level rather than application-level. Smaller but distinct clusters sit in G02B (optical elements, 52), H01L (semiconductor devices, 39), automotive-facing B60R and B60Q (30 and 24), spectacles under G02C (30), and display drive circuitry in G09G (25) — evidence that electrochromic and photochromic claims are being pulled into adjacent product categories rather than staying confined to standalone window or mirror devices.
Shares are the percentage of the 506 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Photochromic and Electrochromic Materials with Eureka
This page is one run against one query. Ask Eureka your own question about photochromic and electrochromic materials and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited and most representative filings
Electrochromic devices with n-doped conductive polymer layers
This disclosure presents electrochromic devices that incorporate an n-doped organic conductive polymer, which can function as a transparent conductor, and/or ion storage material, and/or an electrochromic material in the electrochromic devices.Filed by Ambilight Inc, published 2024-05-16 as US20240160073A1 — notable for using a single polymer class across three functional layers instead of separate metal-oxide and organic components.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6356376B1 | Electrochromic rearview mirror incorporating a third surface metal reflector and a display/signal light | 810 |
| 2 | US5293546A | Oxide coated metal grid electrode structure in display devices | 558 |
| 3 | US6512624B2 | Electrochromic rearview mirror incorporating a third surface partially transmissive reflector | 483 |
| 4 | US6111684A | Electrochromic rearview mirror incorporating a third surface metal reflector and a display/signal light | 467 |
| 5 | US6166848A | Electrochromic rearview mirror incorporating a third surface metal reflector and a display/signal light | 466 |
| 6 | US5384653A | Stand-alone photovoltaic (PV) powered electrochromic window | 312 |
| 7 | US6870656B2 | Electrochromic rearview mirror element incorporating a third surface reflector | 297 |
| 8 | US20130278989A1 | Variable transmittance optical devices | 275 |
| 9 | US7663798B2 | Electrochromic rearview mirror incorporating a third surface reflector | 222 |
| 10 | WO2012079159A1 | Variable transmittance optical devices | 209 |
Citation counts are drawn from the searched corpus and skew toward older filings; treat them as a measure of influence on later filers, not of present-day commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns matter more than any single ranking: where citation weight sits, where filing has slowed, and where classes outside the core optical group are picking up activity.
Rearview mirror architecture still sets the baseline
The five most-cited records in this corpus are all electrochromic rearview mirror patents built around a third-surface metal reflector, with citation counts from 466 to 810. New filings in automotive electrochromics are effectively built on top of this prior art, whether or not they cite it directly.
The growth phase has already passed
Filings rose from 9 in 2017 to a peak of 33 in 2021, then eased to 23 by the 2022 midpoint. That trajectory points to a field where the core device claims are staked out and later filers are refining rather than pioneering.
Claims are migrating into adjacent product classes
Beyond the core G02F and C09K clusters, smaller but consistent activity in B60R, B60Q, G02C and G09G shows electrochromic and photochromic claims being written into automotive trim, eyewear and display products rather than standalone smart windows alone.
The historical leaders have gone quiet
Every one of the assignees with the strongest historical presence in this dataset — spanning both established materials firms and university-linked research institutes — shows zero filings in the most recent year, a gap that newer entrants have room to fill.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to photochromic and electrochromic materials, with the prior art for and against each one.
Who holds the ground, and where the gate sits
Filing history in this corpus is dominated by a small group of automotive-mirror and materials-research assignees, with co-filing relationships that are sparse — only 7 co-assignee pairs across 506 families, and most appearing just once.
Rearview mirror incumbents set the prior art baseline
The heaviest-cited records in this dataset belong to electrochromic rearview mirror filings built around a third-surface metal reflector design, a construction reused across multiple related patents from the same lineage.
Collaboration is rare and mostly single-instance
Co-filing between organisations shows up in only seven pairs, and most of those appear exactly once — this is a field where assignees largely file solo rather than through joint research programmes.
Newer filers are targeting layer-level material claims
Ambilight's 2024 filing on n-doped conductive polymer layers illustrates where newer entrants are competing: not on device architecture, but on the specific material used within the ion storage and electrochromic layers.
| Assignee | Recent year | YoY |
|---|---|---|
| Optical Coating Laboratory | 0 | — |
| Gentex Corporation | 0 | — |
| View Operating Corporation | 0 | — |
| American Cyanamid Company | 0 | — |
| Nitto Denko Corporation | 0 | — |
| Midwest Research Institute | 0 | — |
| University of Connecticut | 0 | — |
| OPPO Guangdong Mobile Communications Co., Ltd. | 0 | — |
Where to take this analysis
The dataset points to a field with settled core architecture and shifting assignee activity. Two directions make sense from here.
Map claims against the ion storage layer cluster
Given how much recent activity concentrates on layer-level material claims rather than device architecture, a claim-by-claim comparison against the ion storage and conducting-polymer filings would show exactly how much room remains before committing to a filing strategy.
Explore this in EurekaTrack assignee momentum before the next filing cycle
With every historically dominant assignee at zero filings in the latest year, watching who files next — and in which IPC subclass — will indicate whether the slowdown is temporary or a genuine shift away from this technology.
Set up monitoring in EurekaCommon questions about this landscape
This dataset includes patent families whose title or abstract references electrochromic material, photochromic material or smart window film, and whose claims or description also touch switching speed, coloration efficiency, cycling durability, ion storage layers or haze. The IPC scope is limited to G02F1, C09K9 and E06B9, which together cover optical modulation devices, chromic materials and window hardware. This combination filters out general optics filings that do not actually claim a chromic switching function.
The dataset's most-cited records are dominated by automotive rearview mirror filings built around a third-surface metal reflector design, a lineage that has generated several related patents with citation counts in the hundreds. Beyond that historical cluster, filing activity has been spread across materials-research organisations and university-linked institutes rather than concentrated in a single company. Notably, every one of the historically prominent assignees in this corpus shows zero filings in the most recent year, meaning current leadership is genuinely open.
Not by the filing trend in this dataset. Filings rose from 9 in 2017 to a peak of 33 in 2021, then declined to 23 by 2022, and have flattened since. Some of the drop in the most recent one to two years is an artefact of publication lag rather than a real falloff, but the overall shape points to a field that has moved past its growth phase into refinement of existing device architectures.
The clearest under-claimed areas sit at the intersection of material chemistry and device layer function: n-doped conducting polymer ion storage layers, haze control in laminated smart window structures, cycling-durability additives, and photochromic eyewear switching speed. These branches show filing activity in the underlying IPC subclasses without a dense citation cluster or a dominant assignee, which suggests the claim space is still being defined rather than locked down.
US20240160073A1, filed by Ambilight, claims electrochromic devices that use an n-doped organic conductive polymer as a transparent conductor, an ion storage material, or the electrochromic layer itself. It matters because it uses one polymer class across multiple functional layers instead of the more conventional combination of separate metal-oxide and organic components. Anyone designing a device with a similar layer structure should review its claims before finalising a material stack.
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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.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
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.