Film Capacitor Patents: Top Companies & Filing Trends 2026
- 312 of 754 records sit with the five leading assignees — 41.4% of everything in scope, so freedom-to-operate work in this field starts with a small set of portfolios, not a long tail.
- Filing peaked in 2018 at 55 and by the 2022 midpoint had dropped to 30 — a flat-to-declining trend, not a growing one, even before the usual publication lag is factored in.
- H01G carries 86.2% of records but H02M (power conversion) and C08L (polymer compositions) sit far lower, at 15.4% and 6.1% — a gap between capacitor-structure claims and the materials and circuit-integration side.
What the dataset covers
This landscape covers 754 published records filed between 2015 and mid-2026, drawn from filings that combine film, metallized-film or DC-link capacitor claims with technical routes such as self-healing metallization, dielectric film thinning, corona inception control, ripple-current handling or high-temperature polymer films. The search restricts to capacitor, polymer-processing and power-conversion IPC classes (H01G4, C08J5, H02M1), so the scope is deliberately narrower than “capacitors” at large — it is the intersection of dielectric film engineering and power-electronics duty cycles.
Because publication typically lags filing by around 18 months, the most recent one or two years in any trend line will look thinner than they eventually turn out to be. That lag does not change the shape of the decline visible from the 2018 peak onward, but it does mean the very last data points should be read as provisional rather than final.
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Filing trend and technology mix
Two views of the same 754 records: how filing activity has moved year over year, and which IPC subclasses carry the claims. Both use the full record set as the denominator, so class shares add up to more than 100% because a single record often carries several classes.
Filing trend, 2017–2026
Activity rose to a peak of 55 records in 2018, then eased; by the 2022 midpoint annual filing had fallen to 30, and the trend line from there is flat to declining rather than recovering. The final years understate true activity because of publication lag, but the multi-year direction predates that effect.
IPC subclass composition
H01G (capacitors) dominates at 86.2% of the 754 records, as expected for a capacitor-centred search. The next tier — H02M power conversion at 15.4%, C08J polymer processing at 12.3%, B32B laminates at 12.2% — shows where capacitor claims connect outward to circuit integration and film manufacture, and each of those is claimed in only a minority of records.
Shares are the percentage of the 754 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Film Capacitors for Power Electronics with Eureka
This page is one run against one query. Ask Eureka your own question about film capacitors for power electronics and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative claim
CA1266518A — Self-healing metallized film capacitor
A self-healing metallized film capacitor built with a dielectric sheet metallized in a high-resistivity alloy chosen to hit a target sheet resistivity at a given metallization thickness. The approach applies generally to metallized film capacitors where electrode thickness and clearability need to be controlled together.Filed by Linzey, Raynor; dated 1990-03-06. Included here as a representative early self-healing claim, not as the most-cited record in the set.
View full record| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6426861B1 | High energy density metallized film capacitors and methods of manufacture thereof | 130 |
| 2 | US8310802B2 | Metallization film capacitor having divided electrode with fuse | 90 |
| 3 | US4609967A | Dielectric fluid for a capacitor | 73 |
| 4 | US20060104006A1 | Film capacitor and method of manufacturing the same | 70 |
| 5 | US4621301A | Dielectric fluid for a capacitor | 70 |
| 6 | US20140286064A1 | Capacitor Device and Electrical Power Conversion Device | 58 |
| 7 | US4599678A | Plasma-deposited capacitor dielectrics | 53 |
| 8 | JP1990250306A | Metallized film for capacitor use | 52 |
| 9 | WO2013069485A1 | Film capacitor, capacitor module, and power converter | 51 |
| 10 | US6187028B1 | Capacitors having metallized film with tapered thickness | 45 |
Citation counts inside a searched corpus favour older filings that have simply had longer to accumulate citations — read this as a signal of influence on later work, not as a ranking of current relevance. The two oldest entries here date to the mid-1980s and both concern dielectric fluid, not film metallization directly.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the concentration and trend numbers mean for strategy
Three findings shape how a team should approach this space: how tight the top of the field is, where filing momentum has actually gone, and which technical routes are structurally under-represented.
A small group holds a large share of the ground
312 of the 754 records in scope belong to the five leading assignees, and the top ten extend that to 375 records — 49.7% of the field. That leaves roughly half of all filings spread across 90 further ranked assignees, so a freedom-to-operate review can reasonably prioritise the leading portfolios first, but cannot stop there.
Filing activity has cooled since 2018
The trend peaked at 55 records in 2018 and had fallen to 30 by the 2022 midpoint, a flat-to-declining pattern rather than a growing one. None of the tracked leading assignees show filings in the latest year in this dataset, consistent with either a genuine slowdown or the normal reporting lag catching up with recent work.
Capacitor-structure claims dominate; circuit-integration claims trail
H01G accounts for 86.2% of the 754 records, unsurprising given the search scope, but the drop-off to H02M power conversion (15.4%) and C08L polymer compositions (6.1%) shows that far fewer filings connect the capacitor structure explicitly to power-conversion circuitry or advanced polymer formulation. That gap is where structural claims and system-level or materials claims are least likely to overlap.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to film capacitors for power electronics, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Toray Industries, Inc. | Aerovox Corporation | 7 |
| Toray Industries, Inc. | Toray Plastics (America), Inc. | 7 |
| Murata Manufacturing Co., Ltd. | Shizuki Electric Co., Inc. | 5 |
| Panasonic Corporation (Japan) | DIALFONE CO LTD | 3 |
| Panasonic Corporation (Japan) | Takeoka Hiroki | 1 |
| Panasonic Corporation (Japan) | Kubota Hiroshi | 1 |
| Panasonic Corporation (Japan) | TAKEOKA HIROKI | 1 |
| Panasonic Corporation (Japan) | KUBOTA HIROSHI | 1 |
Ten co-assignee pairs appear in the dataset; the strongest recurring pairings link a major film producer with downstream capacitor manufacturers, suggesting supply-chain co-development rather than pure in-house filing on the polymer-film side.
Who is filing, and what is left unclaimed
The ranked leaders sit atop a field where roughly half of all filings belong to entities outside the top ten. Recent-year activity across the tracked leading assignees has gone quiet, which changes how a competitive read of this space should be framed.
A clear leader, then a step down
The leading assignee holds 116 records against 31 at fifth place and 11 at tenth — a steep drop inside the top ten itself, not just between the top ten and the rest. That shape points to one or two dominant portfolios worth clearing first in any design-around exercise.
Momentum has stalled at the top even as the base stays large
Every one of the leading assignees tracked for recent-year momentum shows zero filings in the latest year of this dataset. Combined with the 2018 peak and subsequent decline, this suggests the core structural claims in film capacitor design may already be well staked out by incumbents, pushing new activity toward adjacent, less-crowded branches.
Filing is spread across major offices, not concentrated in one
The United States leads with 216 records, followed by Europe at 171 and China at 139, with Japan at 112 and smaller shares through WIPO and India. That spread means a single-jurisdiction clearance search would miss most of the field.
| Assignee | Recent year | YoY |
|---|---|---|
| Panasonic Corporation (Japan) | 0 | — |
| Toray Industries, Inc. | 0 | — |
| Kyocera Corporation | 0 | — |
| Murata Manufacturing Co., Ltd. | 0 | — |
| Shizuki Electric Co., Inc. | 0 | — |
| Ipdia Research Ltd. | 0 | — |
| General Electric Company | 0 | — |
| Panasonic Intellectual Property Management Co., Ltd. | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is clearance, licensing or R&D scoping.
Clear the concentrated top tier first
With 41.4% of records held by five assignees, a freedom-to-operate review gets the most value from starting with the leading portfolios before working down the long tail of 90 further ranked filers.
Explore assignee portfolios in EurekaWatch the under-claimed branches
Power-conversion integration and high-temperature polymer formulation both sit well below the core capacitor-structure share, which is where new claims are less likely to collide with existing density.
Run a white-space search in EurekaTrack whether the slowdown holds
Filing fell from a 2018 peak of 55 to 30 by 2022, and the tracked leaders show no latest-year activity — worth re-checking once publication lag closes on the most recent filings.
Set up trend monitoring in EurekaCommon questions about film capacitor patents
The leading assignee in this dataset holds 116 of the 754 records in scope, with a fairly steep drop to 31 records at fifth place and 11 at tenth. The top five assignees combined account for 312 records, or 41.4% of the field, and the top ten extend that to 49.7%. That leaves roughly half of all filings distributed across the remaining 90 assignees in the ranked set, so the field has a concentrated top but still a substantial long tail.
No, not on the evidence here. Filing peaked in 2018 at 55 records and had fallen to 30 by the 2022 midpoint, a flat-to-declining pattern rather than continued growth. It's worth remembering that publication typically lags actual filing by around 18 months, so the very latest years in any dataset always look thinner than they will eventually turn out to be, but that lag does not explain a multi-year decline starting well before the most recent period.
Self-healing metallization refers to a thin metal layer on the dielectric film, typically a high-resistivity alloy, that vaporizes locally around a dielectric fault so the capacitor keeps operating instead of failing short. The representative record in this dataset, CA1266518A, describes exactly this: a metallization thickness and alloy resistivity chosen so the layer clears itself around defects. It's a foundational mechanism referenced across many of the more recent metallized-film filings in this space.
Beyond the core H01G capacitor classification, which covers 86.2% of the 754 records, the next largest overlaps are H02M power conversion at 15.4%, C08J polymer processing at 12.3%, and B32B layered products and laminates at 12.2%. Because a single record can carry multiple IPC codes, these percentages don't sum to 100% — they show where capacitor claims connect to circuit-level integration, film manufacturing processes, and laminate structures respectively, and each of those connections is present in only a minority of the dataset.
The clearest gaps sit where capacitor-structure claims (H01G, 86.2% of records) have not been matched by claims in adjacent classes: power-conversion integration (H02M, 15.4%), polymer composition formulation (C08L, 6.1%), and motor-drive control overlap (H02P, 3.2%). These lower shares indicate less claim density in those branches relative to the core capacitor structure, which is where a design or filing team is less likely to run into the densest existing coverage.
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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.