US 11121271

I'll research this patent against USPTO records and check for any CAFC 2026 docket activity.

Let me dig deeper into the claim set and check for any litigation/PTAB records.

US Patent 11,121,271 B2 — Analyst Summary

Scope note: All results below are for the specific patent number 11121271 (properly formatted US 11,121,271 B2). I excluded false-positive hits that merely contained the digit string "11121271" (e.g., an unrelated genealogical document "11121252/11121271 James Russell Ranschaert Jr."), and I did not substitute any similar patent numbers.

1. Bibliographic Data

Family / continuity: The patent sits at the end of a long continuation chain. Google Patents lists priority claims from PCT/US2014/039208, US 14/943,898 (now US 9,530,905), PCT/US2016/067977, US 15/797,821 (US 10,446,700), US 16/042,535 (US 10,700,225), PCT/US2018/043289, PCT/US2018/057963, and US 16/296,985 (US 10,468,543). It has non-US siblings JP2021027358A, EP3772104A1, and CN112582387A, and a Korean counterpart KR102358584B1. Related US grants in the same family include US 9,496,435; 10,622,498; 11,391,444; 11,621,360; 11,830,954; 11,791,432; 12,087,871; and 12,243,948.

Ownership caveat: Google Patents also records an October 23, 2024 reassignment to IP LITFIN US 2024 LLC under a "PATENT SECURITY AGREEMENT" — i.e., a security interest, not necessarily an outright assignment of title. The listed assignee/owner remains W&WSens Devices, Inc. I have not independently verified current chain of title at the USPTO Assignment Center.

2. Abstract (verbatim, as published)

"Lateral and vertical microstructure enhanced photodetectors and avalanche photodetectors are monolithically integrated with CMOS/BiCMOS ASICs and can also be integrated with laser devices using fluidic assembly techniques. Photodetectors can be configured in a vertical PIN arrangement or lateral metal-semiconductor-metal arrangement where electrodes are in an inter-digitated pattern. Microstructures, such as holes and protrusions, can improve quantum efficiency in silicon, germanium and III-V materials and can also reduce avalanche voltages for avalanche photodiodes. Applications include optical communications within and between datacenters, telecommunications, LIDAR, and free space data communication."

3. Plain-Language Overview of the Independent Claims

Important uncertainty flag: I was able to retrieve direct claim text only for the higher-numbered claims (via the corresponding pre-grant publication US 2020/0028000 A1, which shares application number 16/528,958). I could not verify the exact wording or numbering of claim 1 or the complete claim set of the issued patent from an authoritative USPTO/Google Patents claim listing within this session. Claim numbering and scope in the issued patent may differ from the pre-grant publication. Treat the following as a functional overview, not a verbatim claim chart.

A. Broad microstructure-enhanced photodetector claim (claim 1-type). A photodetector built in a low-doped or undoped ("I") semiconductor region that is deliberately broken up by an array of "holes" (microstructure cavities). Electrodes create an electric field across the I-region and collect the electrical signal generated when light is absorbed. The holes are sized/spaced to enhance absorption at a selected wavelength and thereby improve the photodetector's electrical response versus an otherwise identical device with no holes.

B. Integrated single-chip photodetector + CMOS/BiCMOS claim. A single-chip structure in which a photosensitive portion sits on one side of a substrate and active CMOS or BiCMOS electronic circuitry sits on the opposite side. The photosensitive portion has multiple sets of P-doped / N-doped / I-regions, with holes formed laterally between the sets. Electrodes carry the photogenerated signals to the active circuit for processing, and output electrodes deliver the processed signals. Key limitation: at least two of the sets are connected to combine their signals into a common signal.

C. "Two-material / avalanche-structure" claim (Ge or GeSi with Si). An integrated single-chip structure with:

• I-regions of a low-doped/undoped first semiconductor material laterally spaced apart by deliberately formed holes in that material;
• regions of that first material doped to one polarity; and
• triplets of a second, different semiconductor material, each triplet consisting of an oppositely-doped region sandwiched laterally between regions of the first polarity.

Adjacent first-material regions are laterally separated by these second-material triplets. The I-regions plus the doped regions act as photodetectors, and the second-material regions are configured as avalanche structures. The specification's worked examples use Ge/GeSi as one material and Si as the other, with multiplication (avalanche gain) occurring in Si and absorption in Ge/GeSi.

D. Ge/GeSi-on-Si interdigitated claim with Gigahertz data rates. A single-chip structure with a first I-region of low-doped/undoped Ge or Ge/Si alloy, a second I-region of low-doped/undoped Si, doped regions of one polarity in the Ge/GeSi, oppositely doped regions in the Si that laterally space the first-polarity regions apart, deliberately formed holes in the Ge/GeSi material, and first and second interdigitated electrodes respectively coupled to the P- and N-doped regions. The structure is claimed as configured to generate electrical signals in response to light and to operate at Gigahertz data rates.

E. Interdigitated lateral claim with hole-separated doped regions. Similar to D but emphasizes that each P-doped region is laterally spaced from an adjacent N-doped region by at least one hole, that a low-doped Si region runs along the Ge/GeSi region on the side opposite the doped regions, and that interdigitated electrodes are coupled to the two conductivity types — again with a Gigahertz-data-rate functional limitation.

F. Claim 28 as published in US 2020/0028000 A1 (back-side-illuminated / stacked architecture): an integrated single-chip structure comprising a photosensitive portion on one side of a substrate and an active CMOS or BiCMOS circuit on the opposite side; plural sets of P-doped / N-doped / I-regions; holes extending in the photosensitive regions and located laterally between the sets; electrodes connecting the doped regions to the active circuit; at least two sets combined into a common signal; and output electrodes from the active circuit.

Recurring inventive themes across the claims:

1. Deliberately formed microstructure holes (unfilled or dielectric/semiconductor-filled) that enhance optical absorption and external quantum efficiency, and can lower avalanche breakdown voltage.
2. Monolithic integration of the photodetector with CMOS/BiCMOS driver/receiver circuitry on the same chip.
3. Lateral, interdigitated (MSM-like or PIN-like) architectures as an alternative to vertical PIN stacks, plus Ge/GeSi-on-Si heterostructures in which absorption and avalanche multiplication occur in different materials.
4. Target applications: datacenter/telecom optical links at 800–1650 nm, LiDAR/SPAD, and free-space optical communication.

4. Litigation / CAFC 2026 Docket Check

No Federal Circuit (CAFC) 2026 docket activity involving US 11,121,271 was found. Targeted searches of Federal Circuit 2026 opinion/order listings and 2026 patent-appeal summaries returned no case citing this patent number. I also did not surface any PTAB IPR/PGR petition or final written decision directed to US 11,121,271 in my searches.

Uncertainty flag: An absence of search hits is not affirmative proof that no appeal or PTAB proceeding exists. Court dockets (PACER) and the CAFC docket system were not directly queried here; only public web indexes were searched. To be definitive, one would need to run a party-name search (W&WSens Devices, Inc.; IP LitFin US 2024 LLC) directly in PACER/CM-ECF and in the CAFC's docket, and check USPTO PTAB "Patent Trial and Appeal Board End-to-End" for the patent number, plus the USPTO Patent Center "Proceedings" tab.

5. Key Sources

• Google Patents, US 11,121,271 B2: https://patents.google.com/patent/[US11121271B2](/patent/US11121271B2)/en
• Google Patents, US 2020/0028000 A1 (same application 16/528,958; source of the claim text quoted above): https://patents.google.com/patent/US20200028000A1/en
• Justia Patents record (assignee, inventors, examiner, classifications): https://patents.justia.com/patent/11121271
• PubChem patent record (cited prior art / NPL): https://pubchem.ncbi.nlm.nih.gov/patent/US-11121271-B2
• Onscope (grant/IPC/status data): https://onscope.com/ipowner/en/owner/ip/[1849561](/patent/1849561)-w-wsens-devices-inc.html
• USPTO Report company page: https://uspto.report/company/W-Wsens-Devices-Inc

If you need the exact issued claim set (all independent and dependent claims, verbatim) or a definitive docket check, tell me and I can focus a subsequent pass on the USPTO Patent Center full-text document and PACER/CAFC docket lookups.

I'll search for litigation involving US patent 11121271.

Let me search more targeted litigation databases.

Let me verify specifically whether US11121271 itself appears in any litigation, distinct from the related-family patents.

Bottom line

I found no litigation — district court, Federal Circuit, or ITC — in which US Patent No. 11,121,271 ("the '271 patent") is asserted, challenged, or otherwise at issue. The '271 patent (assigned to W&WSENS DEVICES, INC.; inventors Shih-Yuan Wang and Shih-Ping Wang; granted Sept. 14, 2021) does not appear as a patent-in-suit in any case I could identify.

Important distinction (do not conflate similar numbers)

The owner of the '271 patent, W&Wsens Devices, Inc., is an active patent plaintiff, but the patents it has asserted are different, related-family patents — not the '271 patent. In particular, be careful with the shorthand:

• In W&Wsens v. Samsung, the "'871 Patent" refers to U.S. Patent No. 12,087,871 — not 11,121,271. These are distinct patents.
• Likewise the "'948" (= 12,242,948), "'360" (= 11,621,360), "'700" (= 10,446,700), "'543" (= 10,468,543), and "'084" (= 9,525,084) patents are family members sharing the same 2013-05-22 priority date, but each is a separate patent from the '271 patent.

The '271 patent and the asserted patents share a common specification family, which is why search hits for the family are easy to mistake for hits on the '271 patent itself.

Related litigation involving the same owner (context only — the '271 patent is NOT asserted)

For completeness, the following is the litigation involving W&Wsens Devices, Inc., none of which asserts US 11,121,271:

Related PTAB proceedings (Samsung as petitioner against W&Wsens):

• IPR2025-00993 (US 12,087,871)
• IPR2025-00994 (US 11,621,360)
• IPR2025-00995 (US 10,468,543)
• IPR2025-00996 (US 10,446,700)
• IPR2025-00997 (US 9,525,084)
• PGR2025-00082 (US 12,242,948)

Institution was denied in several of these (e.g., IPR2025-00995 and -00996) on discretionary/Fintiv grounds, with Director Review also denied in some instances. None of these proceedings involves the '271 patent.

Caveats

• Litigation databases are not exhaustive, and sealed or very recent filings may not surface. I did not retrieve results from PACER directly or from the Unified Patents case list for this specific patent.
• I could not confirm an exact filing date, and I did not verify every docket entry for the E.D. Tex. case.
• My conclusion is limited to the sources retrieved; if a fresh docket search of PACER/CourtListener for "11,121,271" returns a hit that contradicts this, that newer result should be treated as controlling.

If you need a definitive negative clearance, the appropriate next step is a direct PACER docket query and a Lex Machina/Docket Navigator patent-number search for "11121271" (not the family).

Sources: Google Patents (patents.google.com/patent/US11121271B2/en); RPX Insight news (Oct. 27, 2024); Justia dockets for 2:24-cv-00854 (Docs. 127, 261); CourtListener opinion 10742550; Docket Alarm PTAB tracks for IPR2025-00995/-00996; PTAB decision documents (IPR2025-00995/-00996).

I'll verify the ODP "no proceedings" result against the public record before writing anything up.

Samsung appears to have filed a cluster of IPRs against W&Wsens. I need to determine whether any petition targets the '271 patent specifically.

The '271 patent is notably absent from the Samsung IPR cluster. Let me confirm that and check for any other challenge vehicle.

Proceedings overview

Zero AIA trial proceedings have been filed against US 11,121,271. The structured "PTAB proceedings on file" block — sourced from the USPTO Open Data Portal — returns no IPR, PGR, or CBM for this patent, and my independent web searches corroborate that: no petition, institution decision, Final Written Decision, or Federal Circuit appeal naming the '271 patent exists in the public record I could reach. The defensive posture this gives a defendant is neither hardened nor softened — it is untested. There is no claim that has been canceled, and therefore no FWD to hand a panel; but there is also no estoppel, no adverse PTAB construction, and no Board finding that Patent Owner has leaned on. The '271 patent is a virgin claim set in a family whose sibling patents have been under sustained attack — and the attacker has been losing on discretionary grounds, not on the merits.

Because there are no proceedings, the per-proceeding template below cannot be filled for this patent. What follows is (a) a clear statement of that absence, and (b) the family-level proceeding picture, which is the operationally useful intel for anyone holding a demand letter citing the '271 patent.

No proceedings — detail

• Canonical PTAB list (USPTO ODP): empty for US 11,121,271 as of the most recent ingest.
• Web-search cross-check: no IPR/PGR/CBM docket naming U.S. Patent No. 11,121,271 was surfaced. Searches for "11121271" IPR, "11,121,271" PTAB, and W&Wsens 11121271 petition returned only the patent's own Google Patents / Espacenet / PubChem pages and the sibling-patent litigation.
• Caveat (per operating rules): ODP ingest lags. Sibling-patent petitions filed 2025-05-20 onward show a lag pattern in third-party aggregators, so I cannot rule out a very recently filed, unindexed petition against '271. I found no evidence of one.

Why the absence is not an accident

US 11,121,271 (filed 2019-08-01, granted 2021-09-14, priority 2013-05-22, assignee W&Wsens Devices Inc., inventors Shih-Yuan Wang and Shih-Ping Wang) is one member of a large microstructure-photodetector family. In the co-pending district court action, W&Wsens Devices Inc. v. Samsung Electronics Co., Ltd., No. 2:24-cv-00854-JRG (E.D. Tex.), W&Wsens asserted five other family members, not the '271 patent:

Source for the asserted set: W&Wsens' P.R. 3-1/3-2 infringement contentions as reproduced in PTAB filings (https://www.docketalarm.com/cases/PTAB/IPR2025-00994/Samsung_Electronics_Co._Ltd/docs/06-20-2025-Petitioner/Exhibit-1074-Excerpts_from_Plaintiffs_Infringement_Contentions.pdf).

Practical read: the '271 patent is unasserted in the only live W&Wsens campaign I could identify, and therefore un-petitioned. If a demand letter cites the '271 patent, you are dealing with either a new assertion campaign or a portfolio-wide licensing shakedown rather than a patent the market has already stress-tested.

Family-level PTAB picture (context, not '271 proceedings)

Samsung Electronics Co., Ltd. (with Samsung Electronics America, Samsung Semiconductor, and Samsung Austin Semiconductor) filed a coordinated cluster of six AIA petitions against W&Wsens family members in 2025. Every one I could trace was denied institution on discretionary grounds — none reached the merits.

What happened in the denials (IPR2025-00995 / -00996, the best-documented): the deciding official — Acting Chief Administrative Patent Judge Kalyan K. Deshpande, exercising Director review authority — denied institution based on settled expectations (the patents had been in force roughly six years) combined with evidence that Samsung had been on notice of the W&Wsens portfolio since at least 2019–2020, and on Fintiv-type efficiency grounds (parallel E.D. Tex. case with duplication/consistency concerns). Samsung filed Requests for Director Review on 2025-11-17; W&Wsens filed an authorized response 2025-11-25; the Board denied Director Review on 2026-01-12, and post-institution fees were refunded (notice 2026-03-09).

Sources: https://www.docketalarm.com/cases/PTAB/IPR2025-00995/Samsung_Electronics_Co._Ltd._v._W%26Wsens_Devices_Inc/ and https://www.docketalarm.com/cases/PTAB/IPR2025-00996/Samsung_Electronics_Co._Ltd._v._W%26Wsens_Devices_Inc/.

Petition grounds (family IPRs): § 102 and § 103 challenges with substantial prior-art portfolios (the IPR2025-00995 exhibit list alone spans dozens of references from 1991 forward), plus third-party product-teardown evidence (TechInsights Galaxy S5/S6 teardowns) and sensor-public-availability exhibits. The '360 petition also touched priority/§ 112 issues. None of these grounds was adjudicated, because no trial was instituted.

Strategic summary

Claim status for the '271 patent: entirely UNTESTED. There is no canceled claim, no sustained claim, and no claim-level holding of any kind — PTAB or Federal Circuit. Every claim of US 11,121,271 stands exactly as issued. I cannot tell you that claims 1–5 are dead, because nothing has happened to them.

Estoppel landscape: no § 315(e)(2) estoppel attaches to the '271 patent at all. Estoppel under § 315(e)(2) arises only after a final written decision; there has been no IPR on this patent, so no petitioner — Samsung or anyone else — is estopped from raising any prior-art ground against it. For a defendant, that cuts both ways: you are free to bring whatever § 102/§ 103 art you can find, and equally there is no prior petitioner's work product or admitted-claim-construction record to inherit. Note separately that the denied family petitions produce no estoppel either — non-institution leaves Samsung free to run the same art as invalidity defenses in E.D. Tex., which is precisely what the Fintiv denials contemplated.

Pattern signals. W&Wsens (Shih-Yuan Wang / Shih-Ping Wang; now subject to a 2024-10-23 patent security agreement with IP Litfin US 2024 LLC) is an aggressive but narrow-margin enforcer: it sues on a subset of its family, and it has been winning at the institution stage on settled-expectations and Fintiv grounds rather than on the merits. Samsung is a determined, repeat petitioner but is 0-for-0 on getting a W&Wsens patent instituted. The reoccurring vulnerability defendants have exploited is priority: Samsung contends the later-issued family members (the '948, '360, and '871 patents) are entitled only to a 2021-11-22 priority date rather than 2013-05-22, which the court permitted Samsung to add by amendment (W&Wsens Devices Inc. v. Samsung Elecs. Co., No. 2:24-cv-00854-JRG, Dkt. 127 (E.D. Tex. 2026-02-20), https://law.justia.com/cases/federal/district-courts/texas/txedce/2:2024cv00854/233673/127/). No defensive aggregator (e.g., Unified Patents) appears anywhere in the chain I could trace.

Also material to a '271 defense: in the E.D. Tex. claim construction, the court rejected W&Wsens' broad "mere absence of material" reading and construed "hole" as "a void whose primary purpose is to increase the absorption of light entering the void by the light absorbing material abutting the void," reasoning that the specifications consistently treat holes as absorption-enhancing microstructures distinct from isolation trenches (https://www.govinfo.gov/content/pkg/USCOURTS-txed-2_24-cv-00854/pdf/USCOURTS-txed-2_24-cv-00854-2.pdf). That construction was entered in the sibling patents ('700, '543, '360, '871, '948) — the '271 patent's claims were not construed in that order, because it is not asserted. But the '271 specification shares the same disclosure, so the same intrinsic-evidence reasoning would be portable if '271 is ever construed.

Recommended next steps

1. Verify freshness before you rely on the zero count. Check PTAB E2E / P-TACTS for the patent directly: https://ptacts.uspto.gov/ptacts/ — search by patent number 11,121,271. Also re-query the ODP endpoint. My check is current as of the searches run here; ODP ingest lag of weeks-to-months is documented in this family (sibling petitions took weeks to appear), so a petition filed in the last few months could be invisible.
2. Do not cite "PTAB invalidated the claims" — it is false. If you are a defendant, your defenses are district-court defenses: § 102/§ 103 on the merits, and priority/§ 112 written-description attacks following the Samsung playbook (the 2021-11-22 priority theory and the "hole" claim-construction fight).
3. If you file an IPR against '271 yourself, expect the same discretionary-denial wall Samsung hit: the patent will be ~5 years old, W&Wsens will allege you had long-standing notice, and if there is a parallel district court case with a trial date near or before the projected FWD, Fintiv + settled expectations is the likely disposition. Filing a Sotera-type stipulation (as Samsung did in its 2025 filings) and targeting a patent not yet asserted in litigation are the levers that have moved these panels recently.
4. Watch the E.D. Tex. case: trial-stage milestones and the priority ruling there will drive whether the family survives at all, and '271 could be pulled into that case later (a plaintiff can add an asserted patent). Under § 315(b), a petition filed more than one year after service of a complaint alleging infringement of '271 is time-barred — so if '271 is ever added to a complaint, that date starts a hard one-year clock.
5. No pending trial-stage milestones to track for '271: no institution decision deadline, no oral hearing, no FWD due date, because no trial exists.

Confidence and gaps: I have high confidence in the zero count for '271 as of the most recent indexes I could reach. I have lower confidence on (a) the exact filed-dates of IPR2025-00993/-00994/-00997 and PGR2025-00082 (aggregators disagree — one source lists IPR2025-00993 as 2025-06-25, another as 2025-05-20), and (b) the current status of IPR2025-00997 and PGR2025-00082, which I could not verify before running out of search budget. I have not confirmed those dispositions and do not represent them as denials. Nothing above should be read as a claim-level outcome for US 11,121,271 — no such outcome exists.

I'll research the assignment record for US 11,121,271, focusing on USPTO Assignment Center records and any NPE-linked entities in the chain.

Let me dig into the specific assignee entity and any recorded reel/frame data.

Data-provenance note

I was able to retrieve the substance of the recorded chain from Google Patents' legal-events tab (which mirrors USPTO assignment data) plus secondary sources, but I could not retrieve the nine-digit reel/frame numbers or the correspondents of record for the two recorded events within this session. I flag every place where a reel/frame would normally appear. I did not invent any. Where a value is unverified, I say so rather than guess.

Inventors

Notes / unusual patterns.

• The two inventors are the sole named inventors on the '271 patent and are also the founders/principals of the assignee W&WSens Devices, Inc. The classic "all inventors depart within 12 months of filing" precursor to a fire-sale is therefore not present — the inventors are the owner.
• No assignment from HP or any other employer is recorded. The invention appears to be inventor-owned and assigned directly to the founders' own company, which is the norm for W&WSens's whole family.
• M. Saif Islam (UC Davis) appears as a co-inventor on sibling family members (e.g., the 2018 PCT filings and US 10,468,543) but is not a named inventor on the '271 patent. Do not conflate.

Original assignee

• W&WSens Devices, Inc., Los Altos, CA — the entity named on the issued '271 patent.
• Primary line of business: silicon photonics / CMOS image sensor IP — "Semiconductor, Optical communication, Lidar, Data centers." PatSnap classifies it as a "Holding Company / Startup," <10 employees, founded 2014, ~81 patents/siblings across the family. GoodIP counts ~17 distinct applications.
• Product embodying the claims: I found no evidence of a commercial product. W&WSens's public footprint is a website (wwsensdevices.com), conference presentations ("Thin Silicon Photosensors for The Next Generation"; "Time-of-Flight Solutions"), and a 2017 Nature Photonics paper (Wang et al.) — i.e., it is a research/monetization house, not a shipping manufacturer.
• Current status: Active and litigating (see below) — not dissolved, not in bankruptcy. Note the Oct. 23, 2024 security-interest recording, which is a financing encumbrance, not a sale.

Assignment timeline

Recorded chain (per Google Patents legal events, which reproduce USPTO Assignment Center data):

• 2019-08-01 (executed at filing) / recorded on/around 2019-08-01 — Reel/Frame: not retrieved (USPTO Assignment Center query required)

  • Conveyance: Assignment (USPTO category: Assignment of Assignors' Interest)
  • Assignor: WANG, SHIH-PING; WANG, SHIH-YUAN (the two inventors)
  • Assignee: W&WSENS DEVICES, INC.
  • Correspondent: not retrieved this session.
  • Context: Founder-to-company assignment — the inventors conveyed their rights to their own Los Altos corporation at the time of filing. Internal/inception assignment, not a third-party acquisition.

• 2024-10-23 / recorded 2024-10-23 — Reel/Frame: not retrieved

  • Conveyance: Security Agreement (Google Patents legal-event label: "PATENT SECURITY AGREEMENT"; USPTO/Assignment-Center conveyance category: Security Agreement / collateral assignment)
  • Assignor: W&WSENS DEVICES, INC.
  • Assignee / secured party: IP LITFIN US 2024 LLC
  • Correspondent: not retrieved this session.
  • Context: Securitization / litigation financing — a collateral grant over the patent estate to an IP-litigation-finance vehicle ("LITFIN" = Litigation Finance). Title presumptively remains with W&WSens absent default. This is not a sale or a change of owner of record, and it is not a defensive-aggregation transfer.

No other recorded assignments exist for the '271 patent. There is no chain of chained LLCs, no merger, no change-of-name, no release, and no corrective recording in the record. The only two events are the founding assignment and the 2024 security interest.

Important cross-check (do not conflate): At the very same time W&WSens recorded the security agreement (2024-10-23), it had just filed W&Wsens Devices, Inc. v. Samsung Electronics Co., Ltd., No. 2:24-cv-00854-JRG (E.D. Tex.) — the complaint is dated Oct. 21, 2024. That suit does not assert the '271 patent; it asserts family members 9,525,084 / 10,468,543 / 10,446,700 / 11,621,360 / 12,087,871 / 12,242,948. So the security interest is portfolio-wide monetization financing tied to the assertion campaign, but the '271 patent itself is not a patent-in-suit.

Timeline diagram

timeline
    title Ownership of US 11121271
    2013 : Priority application filed
    2019 : Application 16528958 filed
         : Inventors assign to W&WSens Devices
    2021 : Patent US 11121271 issues
    2024 : Security interest recorded to IP LitFin US 2024
         : W&WSens sues Samsung on family patents

NPE / troll-pattern signals

Additional observation (not in the rubric, but material): the presence of a litigation-finance security interest (IP LITFIN US 2024 LLC, recorded 2024-10-23) is itself a monetization signal — it aligns the enforcement campaign for the family with third-party capital. It is, however, an encumbrance, and it does not alter the owner of record.

Verdict

NPE — moderate confidence.

The chain is short and clean: inventors → W&WSens Devices, Inc. (founding assignment, 2019), then a Security Agreement to IP LITFIN US 2024 LLC recorded 2024-10-23. That yields exactly one strong signal — W&WSens is independently classified as a non-practicing entity and is an active patent plaintiff (Stanford NPE database; W&Wsens v. Samsung, No. 2:24-cv-00854, E.D. Tex., complaint Oct. 21, 2024) — plus a monetization/financing signal from the LITFIN security interest. There is no shell-transfer, no cascade, no bankruptcy sale, and no defensive-aggregation terminus, which is why this lands at moderate, not high, confidence.

Three caveats that keep this from being "high": (i) the '271 patent is not asserted in the known campaign; (ii) W&WSens is an inventor-controlled company, not a third-party-acquired shell, so this reads more as a small-entity monetization vehicle than a classic troll structure; and (iii) I could not verify reel/frame numbers or the recording correspondents, which are the evidentiary backbone the rubric asks for.

Verification links

• USPTO Patent Assignment Center (search by patent number 11121271): https://assignmentcenter.uspto.gov/
• Legacy USPTO Patent Assignment Search: https://assignment.uspto.gov/patent/index.html
• Google Patents legal events for the patent: https://patents.google.com/patent/[US11121271B2](/patent/US11121271B2)/en
• Stanford NPE Litigation Database — W&Wsens Devices Inc. v. Samsung (NPE status "Non Practicing Entity"): https://npe.law.stanford.edu/case/[297390](/patent/297390)

To convert "moderate" to "high" or "not," query the Assignment Center by patent number to capture the reel/frame and correspondent of record for both entries, and confirm whether the 2024 security agreement was ever followed by a release or an assignment in lieu of foreclosure — neither of which appears in the data I could retrieve.

I'll research the prior-art citations for US 11,121,271 specifically. Let me run targeted searches.

I have partial data. Let me dig into the specific "Patent Citations" (US patents cited) and non-patent literature lists.

Let me try to retrieve the front-page "References Cited" list directly.

Prior-Art Analysis — US 11,121,271 B2 ("Microstructure Enhanced Absorption Photosensitive Devices")

Important scope/uncertainty statement up front. I was able to retrieve the beginning of the patent's front-page "(56) References Cited — U.S. PATENT DOCUMENTS" list and a substantial portion of its Non-Patent Literature (NPL) citations, but not the complete front-page patent-citation table within this session. The Google Patents HTML rendering suppresses that table, and the PDF was returned only as a fragment. I am therefore giving you (a) the entries I literally retrieved, (b) the full NPL set I could recover, and (c) third-party-identified art from the PTAB/ISA record for the family. I flag every place where the list is incomplete rather than guessing at entries. This is a partial list, not a certified complete one.

I also carry forward, and do not repeat, the earlier sections' flags: the exact issued claim set of the '271 patent was not verbatim-verified in the prior pass, so the §102 mapping below is keyed to the functional claim groups A–F already established, not to literal claim language.

1. Critical threshold issue: the effective filing date controls everything

The '271 patent's earliest priority date is 2013-05-22 (provisional 61/826,446, via PCT/US2014/039208), and it sits at the end of a continuation chain all sharing one specification. Under AIA 35 U.S.C. § 102, the effective filing date for §102(a)(1)/(a)(2) purposes is the earliest claimed priority date to which the claim is entitled. Consequence:

• Any reference published or filed after 2013-05-22 is presumptively not prior art to claims supported by the 2013 disclosure.
• Most of the '271 patent's own NPL citations are 2009–2018 publications. With three exceptions (Bassous 1978; the 1986 Carey InP/GaInAs paper; Collot 1991; the 1989 GaInAs MSM paper; Chang-Hasnain 2012; Liu 1994), they post-date or straddle the 2013 priority date and are 103/background art at most, and for the later-dated ones often not prior art at all.
• The applicant's own earlier family publications (e.g., US 2017/0194522 A1, published July 6, 2017) are same-inventive-entity, same-family disclosures. They would be disqualified under § 102(b)(1)(A) (inventor's own disclosure within the grace period) and/or § 102(b)(2)(C) (commonly owned, same inventors) as to claims entitled to the 2013 priority.

This is the single most important analytical point: the front-page citation list for a 2013-priority continuation is largely not § 102 anticipation art. I will say so plainly rather than force a mapping.

(No contradiction with the earlier sections; this refines the earlier "claim-set not verbatim-verified" flag by adding the priority-date consequence.)

2. Front-page U.S. Patent Documents cited (partial — 2 of N retrieved)

Source: US11121271B2 front page "(56) References Cited / U.S. PATENT DOCUMENTS" (fragment): https://patentimages.storage.googleapis.com/e3/34/b8/554cde586783df/US11121271.pdf

Recommended next step to close this gap: pull the "Patent Citations" table (all rows) from Google Patents' structured data or from the USPTO Patent Public Search full-text of 16/528,958. I could not do so here.

3. Non-Patent Literature cited by / on the face of the '271 patent (recovered partial set)

These are "printed publications," so they can in principle anticipate under § 102(a)(1)/(a)(2) — but subject to the priority-date cut above. Grouped by relevance to the claim groups:

3A. Closest to the hole/microstructure absorption-enhancement theme (claim groups A, C, D, E, F)

3B. Ge/GeSi-on-Si photodiode & MSM art (claim groups B, C, D, E)

3C. APD / SPAD / LiDAR art (LiDAR-SPAD claims added in later continuations)

3D. Nanostructure / absorption-enhancement science (the "why it works" art)

3E. Devices / systems / process art

Sources for § 3: PubChem patent record (https://pubchem.ncbi.nlm.nih.gov/patent/US-11121271-B2), Justia (https://patents.justia.com/patent/11121271#9), and the specification's own incorporated-by-reference list reproduced in the family text.

4. Third-party-identified art (PTAB / ISA) against family members — the most probative record art

This is where the actual § 102 attack in this family lives today. It is directed at siblings, not at the '271 patent, but since they share the specification it is the best predictor of what would be asserted against the '271.

Source: PTAB petition document (ptacts.uspto.gov/.../artifacts..., ISR excerpt listing "US 2017/0194522 A1 (WANG, S et al.)" as X against claims 1–18); plus the earlier sections' litigation/PTAB table, which I am not repeating.

5. § 102 mapping (functional claim groups, with date qualification)

Given (i) the priority-date cut and (ii) the unverified verbatim claim text, here is my honest assessment. No cited reference appears, on its face, to be a clean § 102 anticipation of the broad independent claims for a claim entitled to 2013-05-22.

6. Bottom line

1. The front-page U.S. patent citation list of US 11,121,271 could not be fully retrieved in this session. I recovered only the first two entries (US 4,292,512, Miller et al., 9/1981; US 4,571,559, Henry et al., 2/1986) and I explicitly decline to characterize their subject matter without verification. A complete list must be pulled from Patent Center or the Google Patents citation table.
2. The bulk of the '271 patent's citations are Non-Patent Literature, most of it 2009–2018, i.e., largely post-dating the 2013-05-22 priority date and therefore, for the core claims, not § 102 art at all.
3. The strongest genuine pre-2013 patentability references are Kang et al. (Nature Photonics, Jan. 2009) — Ge-absorption/Si-multiplication APD — and the pre-2013 MSM/SOI literature (Liu 1994; Zang 2008; Bassous 1978; Meng 2012; Chang-Hasnain 2012). Each is a § 103 reference; none squarely § 102-anticipates the independent claims as characterized.
4. The only X-category (anticipating) citation anywhere in the family record is the applicant's own US 2017/0194522 A1, cited against claims 1–18 of a sibling filing — and it should be disqualified as prior art under § 102(b)(1)(A)/102(b)(2)(C).
5. No § 102 anticipation of the '271 patent by a cited reference can be established from the record retrieved here. If any independent claim is not entitled to the 2013 priority date, the leading § 102 candidates become the 2015 ACS Photonics microstructured-hole Si photodiode paper and (for LiDAR claims) the 2016 NIR-SPAD LiDAR paper — both post-2013.

If you want a definitive list, the next step is a full-text pull of the front-page "(56) References Cited" table for application 16/528,958 from USPTO Patent Center, plus the underlying IDS/SB-08 submissions (the family's IDS filings are voluminous — the 2017 filing in app. 15/797,821 alone enclosed ~20 NPL PDFs, per the EFS acknowledgment receipt retrieved).

I'll first try to retrieve the actual "Prior Art" / Citations section for US 11,121,271, since the fetched page text above includes only the prior-art keywords ("cases, holes, microstructure, gesi, doped region") and not the citation list itself.

The fetched page body didn't include the full citation tables. Let me pull the actual cited-art lists for this patent and its immediate family members.

Let me try to nail down (a) the actual issued claim text of the '271 patent and (b) the identity/disclosure of the key cited references, so the §103 mapping rests on real disclosures rather than assumptions.

Obviousness Analysis — US 11,121,271 B2 under 35 U.S.C. § 103

Scope note — what "the Prior Art section of this page" gave me. The fetched Google Patents body for US 11,121,271 truncated the Citations table; what survived on the page itself is the prior-art keyword set ("cases, holes, microstructure, gesi, doped region") plus the specification's own characterizations of the field. I therefore reconstructed the citation record the page indexes from (a) the References Cited sections of the same-family grants US 9,496,435, US 10,622,498 and US 10,700,225 (identical spec, same examiner), and (b) the PubChem NPL list keyed to US-11121271-B2. I flag below which items I verified and which I am inferring.

Two contradictions with the previously generated sections, flagged as required:

1. Claim 1 is mischaracterized upstream. The earlier "Patent summary" described the "claim 1-type" claim as "a broad microstructure-enhanced photodetector… holes sized/spaced to enhance absorption." The actual issued claim 1 of the '271 patent (retrieved this pass from Justia's reproduction of the printed claim set) is entirely different — it is the back-side-illuminated, CMOS-on-the-opposite-side claim with an inverted-pyramid-depth limitation. The earlier "A" characterization appears to describe a claim of a sibling patent, not '271 claim 1. I use the actual text below.
2. Date inconsistency in the task header. The system context says today is 2026-09-29; the task line says 2026-04-26. Statements about docket status (e.g., the Aug. 3, 2026 E.D. Tex. trial setting described upstream) should be treated as date-sensitive.

1. Claim 1 as issued (verbatim, from the printed claim set)

1. An integrated, single-chip structure comprising a photosensitive portion at one side of a substrate and an active CMOS or BICMOS electronic circuit at an opposite side of the substrate, wherein:

• said photosensitive portion … comprises at least one photodetector comprising a P-doped region, an N-doped region, and an I-region of low doped or undoped semiconductor material that is between the N-doped region and the P-doped region and has at least one hole deliberately formed to extend into said photosensitive portion;
• wherein said I-region is essentially single-crystal semiconductor material having inherent crystal planes and said at least one hole extends into said photosensitive portion to a depth exceeding a depth of an inverted pyramid hole with sides along said crystal planes;
• said active circuit … comprises plural active electronic elements;
• connecting electrodes … carry to said active electronic circuit electrical signals generated by said photosensitive portion in response to illumination …; and
• output electrodes … deliver electrical signals processed by the active electronic circuit.

Verified dependent claims: 2 (P/N/I vertically arranged), 11 (portions vertically aligned), 20 (plural pixels, each pixel has only a single one of said holes).

Decomposition. Claim 1 requires only: (A) single chip, photodetector on one face / CMOS-BiCMOS on the opposite face; (B) a P–I–N photodetector; (C) ≥1 deliberately formed hole in the photosensitive portion; (D) the I-region is essentially single-crystal; (E) the hole is deeper than the crystallographic (inverted-pyramid) limit; (F) interconnect and output electrodes. Notably absent: Ge or GeSi, interdigitation, avalanche multiplication, any data-rate limitation, and any express "absorption-enhancement" purpose for the hole.

2. Threshold: effective filing date and prior-art status

• Filed 2019-08-01 (App. 16/528,958); earliest priority 2013-05-22 (prov. 61/826,446) via PCT/US2014/039208 (2014-05-22) and a CIP/continuation chain (2015, 2017, 2018).
• Because Google Patents records 16/528,958 as both a "Continuation" and a "Continuation-In-Part" of earlier cases, each claim's effective date depends on § 112 support in the 2013 provisional.
• Consequence for § 103 — this is the pivotal issue. If any claim is not supported by the 2013 disclosure, its effective filing date shifts to 2014, 2015, 2017, 2018 or 2019, and art in the 2013–2019 window becomes available. In particular:
  • Gao et al., "Photon-trapping microstructures enable high-speed high-efficiency silicon photodiodes," Nature Photonics 11, 301 (2017) — cited in the family — postdates the 2013 priority but predates the 2019 filing. If claim 1's subject matter is not § 112-supported in the 2013 provisional, Gao is 102(a)(1) art and is squarely on point (microstructured holes → high speed + high efficiency Si photodiodes).
  • Uddin et al., Opt. Express (2013), Eshaghi et al., Optik 125, 1478 (2014), Orcutt OFC 2016, Ingham OFC 2017 (all in the family's NPL/IDS record) are likewise unavailable-if-2013 / available-if-later.
  • Han et al. (Deep Trench Isolation and Inverted Pyramid Array …, May 28, 2020) appears in the PubChem list for US-11121271-B2 but postdates even the 2019-08-01 filing — it cannot be § 102(a)(1) art against '271 at any effective date, and I treat it as non-art (it is presumably IDS carry-over from later-filed continuations). Do not rely on it.
• Self-collision exposure. The applicant's own earlier family publications — WO2014/190189 (2014-11-27), US 2016/0126381 A1 (2016-05-05), US 2016/0254407 A1 (2016-09-01), US 2017/0194522 A1 (2017-07-06) — disclose microstructure-hole photodetectors. Under § 102(b)(1)(A) the inventor's grace period reaches only disclosures made ≤ 1 year before the effective filing date. If a '271 claim is not entitled to 2013, those 2014–2017 publications are more than one year before any later effective date and become § 102(a)(1) prior art that can be combined under § 103. This is the single most potent obviousness posture against '271 (and is the classic risk of a long CIP chain). Caveat: I have not performed the § 112 priority/benefit analysis claim-by-claim; it is the predicate I would establish first.

3. Level of ordinary skill

A POSITA here is an engineer/physicist (M.S./Ph.D. or B.S. + experience) with 2–5 years in Si/Ge photodetector and CMOS-integration design. The field was extremely crowded pre-2013: monolithic Si/Ge receivers, black-silicon light trapping, and back-side-illuminated imagers were all mature. That high skill level strengthens every combination below (KSR, 550 U.S. at 421).

4. Element-by-element mapping and the combinations

Combination 1 (strongest against claim 1) — Kang 09* + *Hu/Chen 07 (or Garnett 10*/*Younkin 03) + Csutak/Youn + Brieger 06* (or *Xie 02)

• Kang `09 supplies the P–I–N Ge/Si photodiode with separate absorption/multiplication and its Si-monolithic integration.
• Hu/Chen 07**, **Garnett 10, Younkin `03 supply deliberate micro-hole/textured absorbers and the reason (absorption length × effective path).
• Csutak / Youn 12** / **Huang 11 supply CMOS/BiCMOS co-integration and the receiver interface.
• Brieger 06** (cylindrical nanoholes in crystalline Si) or **Xie 02 (post-CMOS HAR Si microstructures) supplies the non-pyramidal, deeper-than-pyramid hole.

Motivation (KSR rationales, MPEP 2143):

• (A) Known technique, same way, similar device — light-trapping texturing was applied to Si/Ge absorbers to raise quantum efficiency; applying it to the absorber of a monolithic CMOS-integrated photodiode is the same technique for the same reason.
• (B) Simple substitution — replacing a wet-etched pyramidal pit with a dry-etched cylindrical/deep hole is a substitution of one known etch geometry for another, with the predictable result of a greater optical path without the crystallographic depth ceiling.
• (C) Finite number of predictable solutions / "obvious to try" — hole depth, diameter and pitch were recognized result-effective variables; the '271 specification's own FDTD figures (FIGS. 17, 54, 65, 66, 83–84, 88–91) and FIG. 106 data simply tabulate absorption vs. those parameters, i.e., routine optimization.
• (D) Design incentive / market pressure — the '271 specification itself recites the datacenter-interconnect demand for ≥25 Gb/s at 800–1650 nm and admits that no commercial 25 Gb/s Si/Ge-on-Si surface-illuminated PD/APD existed; the `271 text says the microstructure "effectively increase[s] the effective absorption length." KSR, 550 U.S. at 419–20 ("the combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results"), and the absence of a prior commercial product does not rebut a prima facie case.
• (E) No teaching away — none of the black-silicon/nanowire references discourages holes in an absorber; they uniformly promote them.

Combination 2 (against claim 1, "self-collision" variant)

If the effective filing date is not 2013-05-22, then WO2014/190189 / US 2016/0126381 A1 / US 2016/0254407 A1 / US 2017/0194522 A1 (applicant's own, commonly owned) provide the microstructure-hole photodetector element in the same Ge/Si-on-oxide context. Combined with any single CMOS-monolithic-receiver reference (Csutak; Youn `12), claim 1 becomes a combination of two familiar elements with predictable results. Note the § 102(b)(2)(C) common-ownership exception neutralizes these documents as § 102(a)(2) art but does not remove them as § 102(a)(1) printed-publication art once they fall outside the one-year grace window. This is where I would focus the attack, and where I would expect the priority/§ 112 fight to decide the case.

Combination 3 (dependents)

• Claim 2 (P/N/I vertical): fully met by Kang 09's vertical SACM stack; also by the family's own cited US 7,795,064 (Pan et al.), "Front-illuminated avalanche photodiode."
• Claim 11 (vertically aligned portions): same as claim 2.
• Claim 20 (each pixel has exactly one hole): the narrowest and most defensible claim. It would rest on a single-microstructure-per-pixel BSI-pixel reference combined with a monolithic OEIC reference; I did not verify a reference in this page's prior-art record that expressly discloses exactly one hole per pixel and the opposite-face CMOS arrangement. Expect the patentee to point to the specification's FIG. 105/107 single-hole pixel and its experimental EQE data (FIG. 55: EQE vs. reverse bias; FIG. 106: absorption enhancement) as evidence of unexpected results with nexus.

Combination 4 (for the broader, non-claim-1 independent claims — unverified claim text)

I could not verify verbatim text for the Ge/GeSi interdigitated, avalanche, or "Gigahertz data rate" independent claims; the earlier section's descriptions B–E derive from the pre-grant publication US 2020/0028000 A1. On those descriptions, the obviousness case is stronger, because the missing claim-1 limitations are supplied by Kang 09 (Ge absorber / Si multiplier, avalanche in Si — and expressly incorporated into the '271 specification), Chen 09 and Feng 09 (Ge-on-Si high-speed PDs), plus the '271 specification's own FIG. 1 description of an interdigitated MSM Ge/GeSi photodetector as background. A "Gigahertz data rate" functional limitation is a result the prior art (Kang 09's 340 GHz GBP; Csutak; Youn 12's 10 Gb/s; Huang 11's 10 Gb/s) already achieved.

5. Where the obviousness case is weakest

1. The § 102(b)(1)(A)-protected window / priority. If claim 1 is § 112-supported by the 2013-05-22 provisional, all post-May-2013 references — including Gao 2017, Uddin 2013, Eshaghi 2014 and the family's own later publications — drop out, and the attack must be built entirely on pre-2013 art (Kang 09, Hu/Chen 07, Garnett 10, Younkin 03, Yuan 09, Csutak, Radovanovic 05, Xie 02, Brieger 06). That is still a viable combination, but weaker.
2. The "purpose" gloss on "hole." In W&Wsens v. Samsung (E.D. Tex. 2:24-cv-00854-JRG) the court construed "hole" as "a void whose primary purpose is to increase the absorption of light entering the void by the light absorbing material abutting the void." Genuine deep-trench-isolation art (e.g., the DTI of Han-style CIS structures) would therefore fall outside the claim. The combination must instead rest on voids that are for absorption — which the black-silicon / nanowire / nanohole references are, so the workaround is available but narrower.
3. Secondary considerations. The specification carries real experimental data (FIGS. 14, 55, 56, 67–70, 106) showing EQE enhancement, impulse response and ~% capacitance change with vs. without microstructure holes. A patentee asserting nexus between those results and the challenged claims could rebut a prima facie case — though for claim 1 the data are largely directed to the hole element and not to the opposite-face CMOS arrangement, weakening nexus.
4. No PTAB test case. Samsung has petitioned against six family members — IPR2025-00993 ('871), -00994 ('360), -00995 ('543), -00996 ('700), -00997 ('084), and PGR2025-00082 ('948) — but not against '271. Institution was denied in at least -00995 and -00996 on discretionary/Fintiv grounds. So there is no adjudicated art-based record on '271's claims; the analysis above is my own and has not been tested by an examiner or the Board.

6. Bottom line

• Claim 1 is a combination of four independently known elements — (i) monolithic photodetector + CMOS/BiCMOS receiver (Csutak; Youn 12; Huang 11; Assefa 13), (ii) a P–I–N absorber (Kang 09, expressly incorporated into the specification), (iii) deliberate micro-holes in a single-crystal semiconductor absorber for light trapping (Hu/Chen 07; Garnett 10; Younkin 03; Yuan 09; Korevaar US 7,893,348; Graham US 2012/0221866), and (iv) a non-crystallographic (deeper-than-pyramid) hole geometry (Brieger 06; Xie 02; Chang 10). All four KSR rationales apply, and the specification's own admissions supply the motivation. A prima facie § 103 case is available provided the references predate the operative effective filing date.
• The outcome turns on the priority/§ 112 question, not on the art. If the '271 claims cannot claim 2013-05-22, Gao 2017 plus the applicant's own 2014–2017 publications are devastating. If they can, the case must be run on pre-2013 art only and is materially weaker.
• Dependent claim 20 ("only a single one of said holes" per pixel) is the strongest candidate for survival.

Caveats I will not paper over: (a) I could not open the Google Patents Citations table for '271 directly — the identity set above is reconstructed from same-family grants and the PubChem NPL list keyed to US-11121271-B2; (b) I have not verified the specific disclosure of every listed reference (e.g., Bassous US 5,525,828, Dickenson US 7,251,386, Kwark US 6,538,299, Cheng US 7,264,982), and I have deliberately not asserted their content; (c) I could not retrieve verbatim text for the non-claim-1 independent claims; (d) I have not run the § 112 benefit analysis that governs everything in § 2.

Sources: Google Patents US 11,121,271 B2 (https://patents.google.com/patent/[US11121271B2](/patent/US11121271B2)/en); Justia claim text for US 11,121,271 (https://patents.justia.com/patent/11121271); PubChem patent record (https://pubchem.ncbi.nlm.nih.gov/patent/US-11121271-B2); US 9,496,435 B2, US 10,622,498 B2 and US 10,700,225 B2 printed front pages (patentimages.storage.googleapis.com); W&Wsens v. Samsung, No. 2:24-cv-00854-JRG (E.D. Tex.).