Chip on Film and Panel Bonding Patents: Who Leads the Field 2026
- 65.7% concentration. The top five assignees alone account for 3,334 of the 5,075 records in scope — filing here is not evenly spread, it sits with a small group of display makers.
- Filing has cooled from its 2017 peak. 422 records published that year against 15 so far in the most recent (partial) year, with a documented -42% swing from 2021 to 2024 — though recent years understate real activity due to publication lag.
- H01L dominates, but not alone. 64.5% of records carry a H01L semiconductor-device class, while G02F, H10D and H10K each cover a meaningful secondary slice — bonding claims rarely sit in just one class.
Filing growth compares 2021 (272 records) with 2024 (159) — 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 5,075 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Chip on film (COF) and panel bonding technology sits at the junction of semiconductor packaging and display assembly: anisotropic conductive film (ACF) bonds, outer lead bonding, fine-pitch interconnects and the inspection routines that verify contact resistance after bonding. This landscape covers 5,075 published records filed between 2015 and mid-2026, drawn from a search built around ACF, outer lead bonding and fine-pitch bonding terms paired with process-control concerns like bonding temperature profile, warpage of film and post-bond inspection.
The field is defined less by a single breakthrough than by incremental control of a manufacturing step: getting conductive particles reliably captured between bond pads at shrinking pitch, and proving that the bond survives thermal and mechanical stress. That framing shows up in the assignee and class data below.
Filing trends and technology composition
Two views of the same 5,075-record dataset: how filing volume has moved year over year, and which IPC subclasses the records fall into. Both use the full record set as their denominator.
Filing trend, 2017–2026
Filings peaked at 422 in 2017. By 2021 the annual count had settled at 272, then fell to 159 in 2024 — a documented -42% move over that three-year span. 2025 and 2026 figures are still climbing as publications catch up with filing dates, so treat the tail of the chart as incomplete rather than as evidence of continued decline.
IPC subclass composition
H01L (semiconductor devices) appears on 64.5% of the 5,075 records, making it the dominant class by a wide margin. G02F (optical control and modulation, 22.7%), H10D (21.6%) and H10K for organic semiconductors including OLED (17.6%) form a secondary tier, with H05K printed-circuit classes and H05B heating-circuit classes each covering just over a tenth of records. Because a single record can carry several IPC codes, these shares sum to well over 100%.
Shares are the percentage of the 5,075 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Chip on Film and Panel Bonding with Eureka
This page is one run against one query. Ask Eureka your own question about chip on film and panel bonding and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US20050127936A1 — Test pad array for contact resistance measuring of ACF bonds on a liquid crystal display panel
Filed by AU Optronics, this record describes a test pad array and dummy lead array built onto the surface of a liquid crystal display panel specifically to measure the contact resistance of anisotropic conductive film bonds after they are made. The test pad array connects to terminal pads already bonded via ACF, letting a manufacturer measure bond quality directly on the finished panel rather than on a separate test coupon, while the dummy lead array supports connecting a second electronic device to the same panel.Dated 2005-06-16 — one of the earlier attempts in this dataset to formalise post-bond inspection as a testable, on-panel structure rather than a destructive or off-panel check.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US7674650B2 | Semiconductor device and manufacturing method thereof | 4,774 |
| 2 | US7732819B2 | Semiconductor device and manufacturing method thereof | 4,380 |
| 3 | US20090073325A1 | Semiconductor device and method for manufacturing the same, and electric device | 4,254 |
| 4 | US20090152541A1 | Electronic device, semiconductor device and manufacturing method thereof | 4,226 |
| 5 | US20070072439A1 | Semiconductor device and manufacturing method thereof | 1,907 |
| 6 | US20080308805A1 | Semiconductor Device and Manufacturing Method Thereof | 1,279 |
| 7 | US20090008639A1 | Semiconductor Device and Manufacturing Method Thereof | 1,088 |
| 8 | US20080308796A1 | Semiconductor Device and Manufacturing Method Thereof | 1,031 |
| 9 | US7910490B2 | Semiconductor device and manufacturing method thereof | 897 |
| 10 | US20080308806A1 | Semiconductor Device and Manufacturing Method Thereof | 891 |
Citation counts reward older filings that have had more time to accumulate citations within the searched corpus — read them as a signal of influence on the field, not as a ranking of current technical importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the data says about where this field is headed
Three patterns stand out once volume, concentration and class composition are read together.
Filing sits with a small group of leaders
The top five assignees combine for 3,334 of the 5,075 records in scope, and the top ten extend that to 71.8%. A new entrant is not filing into open territory at the core of the technology — they are filing around positions already held by a handful of display and semiconductor manufacturers.
Volume has pulled back from its 2017 peak
Annual filings ran as high as 422 in 2017 and had fallen to 159 by 2024, a -42% move across that three-year window. Several leading assignees show sharp year-on-year declines in the most recent tracked year, though publication lag means the last one to two years of data are still incomplete and should not be read as a final verdict on activity.
Bonding claims cross semiconductor and display classes
Nearly two-thirds of records carry a H01L semiconductor-device class, but meaningful shares also sit in G02F optical-control, H10K organic-semiconductor and H05K printed-circuit classes. A claim drafted purely as a display invention risks missing prior art filed as a semiconductor-packaging invention, and vice versa.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to chip on film and panel bonding, with the prior art for and against each one.
Who holds the ground, and where it is thinning
The assignee ranking is dominated by a small set of display and semiconductor manufacturers, several of which co-file with named inventors repeatedly enough to form clear collaboration clusters. Momentum in the latest tracked year is down sharply for most of the largest filers, which is consistent with the overall volume pullback rather than a sign any one company has withdrawn from the space.
One assignee dominates the ranking outright
The top-ranked assignee holds 2,518 of the 5,075 records in scope, far ahead of fifth place at 78 and tenth place at 61. That gap between first and the rest of the field is the single clearest structural fact in this dataset.
A steep drop-off after the leader
Filing counts fall from thousands at the top to double digits by fifth and tenth place, and continue thinning across the rest of the ranked 100 companies. This is a field with one dominant filer and a long tail of moderate and single-digit filers rather than a tight cluster of comparable competitors.
Inventor-assignee pairings cluster tightly
The strongest co-assignee pairing in this dataset appears on 63 shared records, with two further pairings in the 26-36 range. These patterns point to a small number of long-running inventor teams operating inside the top-filing organisation rather than broad cross-company collaboration.
| Assignee | Recent year | YoY |
|---|---|---|
| Semiconductor Energy Laboratory Co., Ltd. | 6 | -84% |
| Samsung Display Co., Ltd. | 3 | -86% |
| Samsung Electronics Co., Ltd. | 2 | +100% |
| LG Display Co., Ltd. | 0 | -100% |
| Seiko Epson Corporation | 0 | -100% |
| Canon Inc. | 0 | — |
| YAMAZAKI SHUNPEI | 0 | — |
| Japan Display Inc. | 0 | -100% |
Where to take this analysis
The dataset points to specific next questions depending on whether the goal is freedom-to-operate, whitespace scouting, or tracking a competitor.
Check claim scope before filing
With 65.7% of records held by five assignees, a new filing in the ACF or fine-pitch bonding core needs a freedom-to-operate check against those specific portfolios before drafting claims.
Explore assignee claims in Eureka →Track the momentum shift
Several leading assignees show double-digit percentage declines in the latest tracked year. Confirming whether that is a genuine pullback or a publication-lag artefact needs a rerun once another 12-18 months of data lands.
Set up a filing-trend alert in Eureka →Scope the under-claimed branches
Sub-areas like warpage-compensated bonding and post-bond inspection methods show thinner density than the semiconductor-device core. A focused prior-art pull on these terms narrows down real white space fast.
Run a white-space search in Eureka →Common questions about this landscape
One assignee holds a clearly dominant position with 2,518 of the 5,075 records in scope, well ahead of the rest of the ranked field where fifth place sits at 78 records and tenth place at 61. The top five assignees combined account for 65.7% of all records, and the top ten extend that to 71.8%. Beyond the leading names, filing activity thins quickly into a long tail of companies with single-digit or low double-digit counts, so the practical picture is one dominant filer plus a wide field of secondary players rather than several comparably sized competitors.
Filings peaked in 2017 at 422 records and have declined since, with a documented -42% move from 272 records in 2021 to 159 in 2024. That said, publication typically lags actual filing by around 18 months, so the low counts shown for 2025 and 2026 in this dataset are incomplete rather than a sign the field has stopped attracting filings. The safest complete-year comparison available is 2021 to 2024, and that comparison already shows a real pullback rather than steady growth.
This filing from AU Optronics describes a test pad array and dummy lead array built onto the surface of a liquid crystal display panel to measure the contact resistance of anisotropic conductive film bonds after bonding is complete. It is narrowly about the physical inspection structure — on-panel test pads connected to bonded terminal pads — rather than about the bonding process, materials or equipment itself. Anyone designing a new post-bond inspection method that relies on on-panel test pad arrays connected to terminal pads should review this filing's specific claim language, but it does not appear to reach general fine-pitch bonding or ACF material claims.
The dominant class is H01L, covering semiconductor devices generally, which appears on 64.5% of the 5,075 records in scope. Secondary classes include G02F for optical control and modulation at 22.7%, H10D at 21.6%, and H10K for organic semiconductors including OLED technology at 17.6%. Printed-circuit assembly (H05K) and electric heating and lighting circuits (H05B) each cover just over a tenth of records, and because records commonly carry more than one class, these shares add up to well over 100% of the total.
The clearest signal of white space is structural: with 65.7% of all records concentrated among five assignees, any sub-area not directly tied to that group's core claims is comparatively open. Specific branches worth checking include warpage-compensated film bonding, post-bond contact resistance inspection methods distinct from the AU Optronics test-pad approach, and fine-pitch bonding adapted for foldable panel geometries. None of these appear as dominant classes in the IPC breakdown, which is consistent with them being less densely claimed than the H01L semiconductor-device core.
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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.