Thermistors and Varistors Patents: Who Leads, Trends 2026
- Filing has flattened, not grown. the field rose to a 2024 peak of 10 records after a 2017 count of 9, with the 2022 midpoint at 8 — a plateau rather than a growth curve.
- The top 5 hold just over a third of the field. 56 of 157 records (35.7%) sit with the five leading assignees, with a longer tail filling out the remaining ranked companies.
- Resistor claims dominate; protective-circuit claims lag. H01C covers 84.7% of records while H02H protective circuit arrangements cover only 6.4% — a gap between the ceramic/resistor core and surge-protection integration.
What this landscape covers
This landscape tracks patent filings at the intersection of NTC and PTC thermistors and metal oxide varistors, scoped to claims that address resistance-temperature characteristics, inrush current limiting, self-heating and degradation after surge. The search string combines title terms for the three device families with claim-description language on B value and surge behaviour, restricted to IPC classes H01C7, G01K7 and H02H9. The dataset spans 2015-01-01 through 2026-07-31, with 157 published records in scope.
Because publication trails filing by roughly 18 months, the 2025 and 2026 counts in the trend chart understate actual filing activity for those years; treat the most recent two data points as provisional rather than a real decline.
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Filing trend and technology composition
Two views of the same 157 records: how filing volume has moved year over year, and which IPC subclasses carry the claim density.
Filing trend, 2017-2026
Volume rose to 9 records in 2017, held near a midpoint of 8 in 2022, and reached its peak of 10 in 2024 before the partial, still-understated 2026 count of 1. The shape is a plateau, not sustained growth — read it as a mature, steadily-occupied claim space rather than an expanding one.
IPC subclass composition
H01C (resistors) appears in 84.7% of records, confirming this is fundamentally a resistor-materials field. C04B (ceramics) at 26.1% and G01K (temperature measurement) at 21.0% show the two largest adjacent branches, while H02H (protective circuits) at 6.4% and H02K (motors/generators) at 3.8% mark the thinnest-claimed intersections with device integration. Records can carry multiple classes, so these shares sum to more than 100%.
Shares are the percentage of the 157 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Thermistors and Varistors with Eureka
This page is one run against one query. Ask Eureka your own question about thermistors and varistors and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
NTC thermistor ceramic, method for producing NTC thermistor ceramic, and NTC thermistor
A ceramic main body composed of a (Mn,Ni)3O4- or (Mn,Co)3O4-based material forms a first phase with spinel structure and a second phase of high-resistance plate crystals dispersed within it. A heated pathway of a predetermined pattern is formed on the ceramic surface by laser irradiation; within that pathway the second phase disappears and becomes crystallographically equivalent to the first phase. The plate crystals precipitate at 800°C or lower during the firing cooling substep, giving localised control over resistance along the laser-defined pattern.Filed by Murata Manufacturing Co., Ltd. — a laser-patterning approach to localised resistance control in NTC ceramic bodies.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5854471A | Apparatus using a thermistor with a positive temperature coefficient | 73 |
| 2 | US6522237B1 | Electrode for PTC thermistor and method for producing the same, and PTC thermistor | 58 |
| 3 | US3673538A | Composite thermistor temperature sensor having step-function response | 50 |
| 4 | US4924204A | Organic PTC thermistor device | 42 |
| 5 | US3644864A | Composite thermistor temperature sensor having step-function response | 36 |
| 6 | US20050062581A1 | Polymer ptc thermistor and temperature sensor | 33 |
| 7 | US6188308B1 | PTC thermistor and method for manufacturing the same | 33 |
| 8 | US5804797A | PTC planar heater and method for adjusting the resistance of the same | 31 |
| 9 | US20070057759A1 | Ptc thermistor and method for protecting circuit | 23 |
| 10 | GB2047431A | Temperature control means in a humidity pick-up | 23 |
Citation counts reflect influence within this searched corpus and skew toward older filings; they are not a measure of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three findings that shape where a new filing would land in this field, and how much competitive attention it would draw.
The top of the field is dense but not closed
Fifty-six of 157 records sit with five leading assignees, and the tenth-ranked company still holds 4 records — evidence of a long tail of single- and few-filing entrants rather than a market sealed by a handful of dominant portfolios.
Filing has shifted toward Chinese offices
China leads receiving-office volume at 58, ahead of the United States at 30, Japan at 25 and the EPO at 21. A filer targeting global coverage without a China-first strategy is missing the largest single office in this dataset.
Surge-protection integration is thinly claimed
H01C resistor claims cover 84.7% of records, but H02H protective circuit arrangements appear in only 6.4% and H02K motor/generator integration in 3.8%. The core ceramic and resistor materials are heavily claimed; the circuit-level integration around them is not.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to thermistors and varistors, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Guangdong Fenghua Advanced Technology (Holding) Co., Ltd. | Wuhan University of Technology | 2 |
| Guangdong Songtian Electronics Industrial Co., Ltd. | Shantou High-Tech Zone Songtian Industrial Co., Ltd. | 2 |
| Murata Manufacturing Co., Ltd. | MIURA TADAMASA | 1 |
| Nippon Tungsten Corp. | Makoto Sanpara | 1 |
| Nippon Tungsten Corp. | KUWABARA MAKOTO | 1 |
Only 5 co-assignee pairs appear across the dataset, and the strongest pairs link corporate assignees to university or affiliate partners rather than competitor-to-competitor collaboration — most filing here is done independently.
Who is filing, and where activity has cooled
The ranked leaders span established electronics manufacturers and a longer tail of smaller filers; recent-year momentum has slowed across the board.
A single leader, then a steep drop to the mid-tier
The leading assignee holds 20 records against a fifth-place figure of 7 and a tenth-place figure of 4 — a steep early drop that flattens into the long tail making up the remaining 61 ranked companies.
Recent-year activity has gone quiet at the top
Several of the most active historical filers, including the top-ranked assignee, show zero filings in the latest year of the dataset. Given the ~18-month publication lag, this understates true recent activity, but it is consistent with the flat 2022-2024 trend rather than renewed growth.
Co-filing is the exception, not the norm
The strongest co-assignee links pair a corporate filer with a university partner or a closely affiliated regional entity, each appearing twice across the dataset. This points to a field where most competitive advantage is built through solo filing rather than joint ventures.
| Assignee | Recent year | YoY |
|---|---|---|
| Murata Manufacturing Co., Ltd. | 0 | — |
| Panasonic Corporation (Japan) | 0 | — |
| Tyco Electronics Raychem KK | 0 | — |
| Nippon Tungsten Corp. | 0 | — |
| Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences | 0 | — |
| Guangdong Fenghua Advanced Technology (Holding) Co., Ltd. | 0 | — |
| Sumitomo Metal Industries, Ltd. | 0 | — |
| TDK Corporation | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, portfolio benchmarking or identifying open filing space.
Map the white space claims directly
The thinnest IPC branches — protective circuits, motor integration, metal-oxide compounds — are where a first claim is least likely to run into dense prior art. Drafting against these branches specifically, rather than the crowded H01C core, is the fastest way to find open space.
Explore white space in Eureka →Benchmark against the ranked leaders
With 61 companies ranked and the top 10 holding just over half the field, a full picture of any single competitor's strategy requires looking past their headline count to filing recency and IPC spread.
Run a competitor benchmark in Eureka →Common questions about thermistor and varistor patents
This dataset identifies 157 published records in scope between 2015 and mid-2026, spanning NTC and PTC thermistors and metal oxide varistors under IPC classes H01C7, G01K7 and H02H9. The assignee ranking covers 157 families across 61 ranked companies. Because publication lags filing by roughly 18 months, the true current total is somewhat higher than what has been published and indexed so far.
The ranking is led by a single assignee holding 20 of the 157 records, with a steep drop to 7 records at fifth place and 4 at tenth place. The top 5 assignees combined hold 35.7% of all records, and the top 10 combined hold 51.6% — meaning roughly half the field is spread across a long tail of 51 additional ranked companies. This is a concentrated-but-not-closed structure: a handful of firms lead, but most of the field is still open to smaller filers.
Filing volume has been flat rather than growing: 9 records in 2017, 8 at the 2022 midpoint, and a peak of 10 in 2024. The 2025 and 2026 figures appear lower, but that reflects the roughly 18-month lag between filing and publication rather than an actual drop-off. Read the trend as a mature, steadily-occupied field rather than one in decline or in rapid expansion.
The IPC composition shows resistor materials (H01C, 84.7% of records) and ceramics (C04B, 26.1%) as heavily claimed, while protective circuit arrangements (H02H, 6.4%), motor and generator integration (H02K, 3.8%) and metal-oxide compound formulations (C01G, 3.2%) are comparatively thin. These lower-share branches are where a new filing is less likely to collide with dense prior art, particularly around surge-protection circuit integration and material analysis methods (G01N, 2.5%).
China leads with 58 filings in this dataset, ahead of the United States at 30, Japan at 25 and the European Patent Office at 21. WIPO's PCT route and Canada trail well behind at 4 and 3 respectively. A filer building global protection in this space should treat China and the US as the two priority jurisdictions based on this filing pattern.
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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.