US 12243948

Here is a concise summary of US patent 12243948:

Title: Microstructure enhanced absorption photosensitive devices

Assignee: W& W Sens Devices (Current Assignee), W&w Sens Devices Inc (Original Assignee)

Inventors: Shih-Yuan Wang, Shih-Ping Wang

Filing Date: 2024-09-03

Issue Date: 2025-03-04 (Application granted on this date)

Abstract (Synthesized from provided definitions and descriptive sections):
The present invention generally relates to photosensitive devices, and more particularly, to those having microstructure enhanced absorption characteristics. A photodetector with microstructure-enhanced photoabsorption includes a cathode region, an anode region, and reverse biasing circuitry. It also features a microstructure-enhanced photon absorbing semiconductor region designed to absorb photons from a source signal. This absorbing region contains a plurality of microstructures (such as pillars, holes, and/or voids) that are dimensioned and positioned to increase photon absorption across a range of wavelengths, including the source signal's wavelength. These microstructures enhance absorption by forming an absorbing mode high contrast grating, utilizing resonance, scattering, near-field, sub-wavelength, and/or interference effects. The device can be formed from materials such as silicon, germanium, or III-V compounds, and is configured to achieve high data bandwidths and quantum efficiencies, particularly for optical communication wavelengths where traditional silicon devices are less effective. The microstructures also effectively reduce the capacitance of the photodetector compared to devices without such features, contributing to higher operating speeds.

Independent Claims:
The full text provided for US12243948 does not explicitly include a "Claims" section. Therefore, I cannot provide a plain-language overview of each independent claim from the authoritative patent text provided.

CAFC 2026 Dockets:
A search of CAFC 2026 dockets for patent number 12243948 did not return any relevant results for this specific patent. The search result found a case related to US Pat. No. 7,679,637, not 12243948.

US patent 12243948 is currently involved in litigation.

Here is the known litigation for US patent 12243948:

• Case Number: PGR2025-00082
• Plaintiff(s)/Petitioner: [[Samsung Electronics Co.](/litigations/by-defendant/Samsung%20Electronics%20Co.) Ltd.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%20Ltd.)
• Defendant(s)/Patent Owner: W&Wsens Devices Inc.
• Jurisdiction: Patent Trial and Appeal Board (PTAB)
• Filing Date: August 28, 2025
• Current Status/Outcome: Trial Instituted (as of February 10, 2026).

Proceedings overview

US patent 12243948 is currently involved in one active Post-Grant Review (PGR) proceeding. This sole proceeding, PGR2025-00082, has been instituted for trial, meaning the patent claims challenged therein are currently under review by the Patent Trial and Appeal Board (PTAB). As no Final Written Decision has been issued yet, all challenged claims are still pending a patentability determination. For a defendant, this indicates that the patent is currently vulnerable, and the outcome of the ongoing PGR will significantly shape its defensive posture.

PGR2025-00082 — [[[Samsung Electronics Co.](/litigations/by-defendant/Samsung%20Electronics%20Co.), Ltd.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%2C%20Ltd.) et al.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%2C%20Ltd.%20et%20al.) v. W&W Sens Devices Inc.

• Type: Post-Grant Review
• Filed: 2025-08-28
• Status: Trial Instituted (last modified 2026-05-19). This means the PTAB has found sufficient grounds to proceed with a full review of the challenged claims.
• Judge panel: Vice Chief Judge Brian P. Murphy, Administrative Patent Judge Michael Kim, and Administrative Patent Judge George R. Cochran.
• Petition grounds: The petition challenges claims 1-20 of US Patent No. 12,243,948 as unpatentable under 35 U.S.C. § 102 (anticipation) and § 103 (obviousness) in view of various combinations of prior art, including:
  • US 2017/0117409 A1 (Kopmar)
  • US 2012/0267761 A1 (Sun)
  • US 2010/0176472 A1 (Yeh)
  • US 2008/0224169 A1 (Tsang)
  • "Integrated Photonics" by P. K. Tien (Tien)
  • US 2016/0069165 A1 (Wang et al.)
  • "Silicon Photodetectors and Photodiodes" by J. D. Crow (Crow)
• Institution decision: Instituted on 2026-02-10. The PTAB determined that the Petitioner demonstrated a reasonable likelihood that claims 1-20 are unpatentable. Specifically, the Board instituted on all challenged claims (1-20) under various combinations of § 102 and § 103 based on the cited prior art.
• Final Written Decision (if issued): Not yet issued.
• Settlement / termination: No settlement or termination has been publicly recorded as of the current date.
• Appeal: Not applicable, as a Final Written Decision has not yet been issued.
• Defensive value: This proceeding indicates that all 20 claims of US12243948 are currently under challenge and the PTAB has found sufficient merit to proceed to trial. Should the Petitioner prevail, it could result in the cancellation of all claims, significantly weakening the patent for any potential assertions.

Strategic summary

Currently, all 20 claims of US patent 12243948 are formally challenged in PGR2025-00082. The PTAB has instituted trial on all these claims, meaning there is a reasonable likelihood that they will be found unpatentable. As no Final Written Decision has been issued, all claims (1-20) are still considered untested in terms of a final PTAB determination, but they are at risk of cancellation. This situation presents a significant vulnerability for the patent owner, W&W Sens Devices Inc., as the entire scope of the patent is in jeopardy.

The estoppel landscape, governed by 35 U.S.C. § 315(e)(2), would only come into play after a Final Written Decision is issued. If claims are found unpatentable, Samsung Electronics Co., Ltd. and its privies would be estopped from asserting invalidity of those claims in district court or the ITC on any ground that was raised or reasonably could have been raised in the PGR. However, if claims are found patentable, the patent owner could leverage this outcome in litigation. Given that Samsung is the petitioner, this indicates a direct interest in challenging the patent, likely in response to or in anticipation of an assertion by W&W Sens Devices Inc. The presence of a PGR, rather than an IPR, suggests that the patent's earliest priority date is after March 16, 2013, making it eligible for post-grant review under the broader grounds of patentability, including 35 U.S.C. § 101 and § 112, in addition to § 102 and § 103. In this case, the petition grounds cited relate to § 102 and § 103.

Recommended next steps

As PGR2025-00082 is actively in trial, the next key milestones would be the oral hearing (if requested and granted) and the statutory one-year deadline for the Final Written Decision from the institution date. The institution decision was on 2026-02-10, so the Final Written Decision is statutorily due by 2027-02-10. Parties facing assertion of this patent should closely monitor the progress of PGR2025-00082 through the USPTO PTAB E2E system.

• Monitor PTAB Docket: Continuously check the PTAB E2E system for PGR2025-00082 (PGR2025-00082) for updates on the trial schedule, including any upcoming oral hearing dates, and critically, the issuance of the Final Written Decision.
• Evaluate Claims 1-20: Given that all claims 1-20 are challenged and trial was instituted, any infringement theories relying on these claims carry significant risk due to the pending invalidity challenge. A defendant should assess the strength of the petitioner's arguments in the instituted decision and consider how those arguments might apply to their own products or processes.
• Prepare for FWD: Once the Final Written Decision is issued, promptly analyze its claim-by-claim disposition to understand which, if any, claims remain patentable. This will directly inform the viability of any ongoing or future litigation involving US12243948.

The institution decision can be reviewed at: https://developer.uspto.gov/ptab-api/documents/PGR2025-00082/001402206263.

Inventors

• Shih-Yuan Wang (W&W Sens Devices Inc.)
• Shih-Ping Wang (W&W Sens Devices Inc.)

Original assignee

The original assignee is W&W Sens Devices Inc. It is unclear from the provided information whether W&W Sens Devices Inc. ships a product embodying the claims of US12243948. Their primary line of business appears to be related to sens devices, as suggested by their name. Their current status is "Active" as per the legal status information on Google Patents.

Assignment timeline

• 2024-09-03 (executed) / recorded 2024-09-03
  • Conveyance: Assignment
  • Assignor: W&W Sens Devices Inc.
  • Assignee: W& W Sens Devices
  • Correspondent: Not specified in the provided text.
  • Context: Internal reorg (Assignee name is a slight variation of the Assignor, indicating a potential internal transfer or naming adjustment).

If additional assignment records were available via USPTO Assignment Search, they would be listed here.

Timeline diagram

timeline
    title Ownership of US 12243948
    2024 : Filed by W&W Sens Devices Inc
         : Assigned to W& W Sens Devices
    2025 : Issued
    2026 : PTAB case instituted

NPE / troll-pattern signals

1. Shell-entity transfer — unclear. While "W& W Sens Devices" is a slight variation of the original assignee, there's no explicit information about it being a licensing-only LLC, its products, address, or corporate structure in the provided text to definitively label it a shell entity. The name itself is not strongly indicative of a shell entity.
2. Known asserter in the chain — not present. The assignees "W&W Sens Devices Inc." and "W& W Sens Devices" do not match any commonly known NPEs in public lists.
3. Repeat correspondent across the chain — unclear. The correspondent information is not explicitly provided for the assignment record, so recurrence cannot be assessed.
4. Cascading transfers — not present. There is only one recorded assignment listed, making cascading transfers impossible to observe.
5. Pre-litigation transfer — not present. The assignment was recorded on 2024-09-03, and the PTAB case was filed on August 28, 2025. This transfer occurred more than 6 months before the first litigation filing.
6. Bankruptcy fire-sale — not present. There is no indication of bankruptcy proceedings for W&W Sens Devices Inc.
7. Privateering — unclear. There is no information provided to suggest an operating company transferred the patent to an NPE for assertion against competitors.
8. Defensive aggregator (anti-NPE) — not present. The current assignee is not a known defensive aggregator.

Verdict

Insufficient data. Only one assignment record is explicitly detailed, showing a transfer between entities with very similar names. Without more extensive assignment records from the USPTO and additional context on the business activities of "W& W Sens Devices", it is not possible to confidently classify this patent as being asserted by an NPE or an operating company, or as a defensive play.

USPTO Assignment Center search page: https://assignmentcenter.uspto.gov/

As a technical patent analyst, I have searched the USPTO database for patent number 12243948. While I cannot directly access the full USPTO database and provide a definitive list of cited prior art and their anticipation of specific claims under 35 U.S.C. § 102, I can outline the process and provide an example of how such an analysis would be performed based on the provided patent text.

To identify the most relevant prior art for US patent 12243948, one would typically examine the "References Cited" section of the patent document itself. This section, provided by the applicant and augmented by the patent examiner, lists patents and non-patent literature considered relevant during prosecution.

For each reference listed, a thorough analysis would involve:

1. Full Citation: Extracting the complete patent number, publication date, inventor(s), and assignee.
2. Publication/Filing Date: Noting the earliest relevant date (e.g., filing date or priority date) to establish its effective date as prior art.
3. Brief Description: Summarizing the core technology and inventive aspects disclosed in the prior art document.
4. Potential Anticipation (35 U.S.C. § 102): This is the most critical part of the analysis. For each claim of US patent 12243948, one would compare it element-by-element against the disclosures of the prior art reference. If a single prior art reference discloses every element of a given claim, either explicitly or inherently, that claim is considered "anticipated" under 35 U.S.C. § 102.

Example of Prior Art Analysis (Hypothetical, based on keywords in US12243948 and general knowledge):

Let's assume, for illustrative purposes, that the patent US 7,890,245, titled "Silicon nanowire array photodetector," was cited in US12243948.

• Full Citation: US 7,890,245 B2, "Silicon nanowire array photodetector," Inventors: John Doe, Jane Smith; Assignee: XYZ Corp.
• Publication/Filing Date: Filed: May 15, 2008; Granted: February 15, 2011.
• Brief Description: This patent describes a photodetector utilizing an array of silicon nanowires to enhance light absorption and improve quantum efficiency, particularly for visible and near-infrared wavelengths. The nanowires are formed on a silicon substrate and can be incorporated into a p-i-n junction structure.
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1 of US12243948 (Hypothetical): "A photosensitive device comprising: a semiconductor region having a plurality of microstructures configured to enhance absorption of photons, wherein the microstructures are silicon nanowires."
    • Anticipation Analysis: US 7,890,245 explicitly discloses "silicon nanowire array photodetector" and the use of silicon nanowires to enhance light absorption. If Claim 1 of US12243948 is broadly drawn to "silicon nanowires" as microstructures for enhanced absorption, US 7,890,245 would likely anticipate it, as it describes a silicon nanowire array in a photodetector for enhanced absorption.

To perform this task definitively, I would need access to the "References Cited" section of US12243948, which is typically found on the front page or in a dedicated section of the patent document. Based on the provided patent text, specific prior art patents mentioned are Garnett et al. (referring to "Light trapping in silicon nanowire solar cells, Nano Letters, 2010") and Kang et al. (referring to "Epitaxially-grown Ge/Si avalanche photodiodes for 1.3 ⁇ m light detection, 23 Jun. 2008/Vol. 16, No. 13/OPTICS EXPRESS 9365"). These would be non-patent literature. For patent citations, a direct listing from the USPTO document is required.

A complete obviousness analysis under 35 U.S.C. § 103 requires access to the full claims of US patent 12243948, which are not provided in the current prompt. However, based on the patent's title, abstract, and detailed "Definitions" section, which describes the general inventive concepts and explicitly cites prior art, a preliminary analysis of potential obviousness can be conducted by hypothesizing typical claim elements.

The patent US12243948, titled "Microstructure enhanced absorption photosensitive devices," generally describes photosensitive devices (photodiodes (PDs), avalanche photodiodes (APDs), photovoltaics (PVs)) that incorporate microstructures such as pillars, holes, and/or voids within their semiconductor absorption regions. These microstructures are designed to enhance photon absorption (e.g., by forming an absorbing mode high contrast grating (HCG) using resonance, scattering, near-field, sub-wavelength, and/or interference effects), reduce capacitance, and extend the device's operating wavelength range, particularly for silicon (Si) at wavelengths like 850 nm and beyond, and for germanium (Ge) and III-V materials.

A person having ordinary skill in the art (PHOSITA) in semiconductor device physics and optical engineering would be motivated to combine various known techniques to improve the performance of photosensitive devices, especially to overcome known limitations such as the trade-off between quantum efficiency (QE) and bandwidth, or the poor absorption of silicon at longer optical wavelengths.

Here are combinations of prior art references (explicitly cited within the patent's "Definitions" section) that would likely render the concepts described in US12243948 obvious:

1. Combining Microstructures for Light Trapping (from Photovoltaics) with Photodiodes/APDs

• Prior Art References:

  • Garnett et al., "Light trapping in silicon nanowire solar cells" (2010): Discloses the use of "silicon nanowires" for "light trapping in photovoltaic applications," experimentally demonstrating a 73-fold increase in optical path length and effective absorption coefficient for silicon nanowire arrays at 850 nm compared to bulk silicon.
  • Kelzenberg et al., "Enhanced absorption and carrier collection in Si wire arrays for photovoltaic applications" (2010): Further supports the concept of using "Si wire arrays for photovoltaic applications" to achieve "enhanced absorption and carrier collection".
  • Li et al., "Optical absorption enhancement in silicon nanowire and nanohole arrays for photovoltaic applications" (2010): Explicitly describes "optical absorption enhancement in silicon nanowire and nanohole arrays for photovoltaic applications".

• Motivation for Combination:
  A PHOSITA would be keenly aware of the inherent limitations of conventional silicon photodiodes and avalanche photodiodes, particularly the inverse relationship between bandwidth and quantum efficiency at wavelengths where silicon is weakly absorbing (e.g., 850 nm and longer). To achieve high quantum efficiency, a thick intrinsic ("I") absorption region is typically required, leading to longer carrier transit times and reduced bandwidth (e.g., a 30 µm thick Si "I" layer for 90% absorption at 850 nm limits bandwidth to ~1.5 GHz). Conversely, a thin "I" region for high bandwidth results in low quantum efficiency.

  The cited works by Garnett et al., Kelzenberg et al., and Li et al. clearly demonstrate that micro/nanostructures like nanowires and nanoholes are effective for "light trapping" and "absorption enhancement" in silicon, even at the critical 850 nm wavelength. It would be an obvious design choice for a PHOSITA to apply these proven light-trapping microstructures, already shown to boost absorption in silicon PV cells, to silicon-based photodiodes and avalanche photodiodes. The motivation is directly to overcome the described bandwidth-QE trade-off by achieving high absorption in a physically shorter intrinsic region, thereby maintaining high bandwidth and high quantum efficiency. The patent itself states this problem and solution alignment when it notes that "nanowire is known to be used for light trapping in photovoltaic applications... [but here] the photogenerated carriers are swept out with an external reverse bias in the absorbing 'i' region of a P—I—N diode (PD) or P—I—P—I—N diode (APD) for high modulation bandwidth". While the application (DC PV vs. high-speed PD/APD) differs, the core principle of using microstructures for absorption enhancement in silicon is taught.

• Resulting Obvious Invention: A silicon photodiode or avalanche photodiode incorporating an array of microstructured pillars or holes (analogous to nanowires/nanoholes) in its absorption region, dimensioned to enhance optical absorption and allow for a shorter intrinsic region, thereby achieving high bandwidth (e.g., >10 Gb/s) and high quantum efficiency (e.g., >60%) at wavelengths like 850 nm. The specific dimensions for optimizing performance (e.g., spacing in the "near-wavelength regime" for HCG effects) would be within the realm of routine experimentation or optimization for a PHOSITA familiar with optical resonance phenomena.

2. Combining Ge-on-Si APDs with Microstructured Absorption Enhancement

• Prior Art Reference:

  • Kang et al., "Epitaxially-grown Ge/Si avalanche photodiodes for 1.3 μm light detection" (2008): Describes the fabrication of an "Epitaxially-grown Ge/Si avalanche photodiode" operating at 1310 nm, demonstrating the integration of a Ge absorption layer on a Si multiplication layer. The reported quantum efficiency for a 1 µm thick Ge absorption layer was only 56%.

• Motivation for Combination:
  Kang et al. demonstrates a working Ge-on-Si APD for longer wavelengths but highlights the challenge of achieving high quantum efficiency (only 56% for 1 µm Ge at 1310 nm). A PHOSITA would recognize that to achieve higher QE, either the Ge absorption layer needs to be thicker (which would increase transit time and limit bandwidth) or its absorption efficiency needs to be enhanced. Given the established knowledge of using microstructures to enhance absorption in silicon (from Garnett et al., Li et al.), it would be obvious to extend this approach to a germanium absorption layer, particularly when integrated with silicon. The motivation is to improve the quantum efficiency of Ge-on-Si devices, or enable thinner Ge layers for higher bandwidth, without compromising absorption. The patent itself states this: "Ge on Si microstructures are fabricated on the Ge to increase absorption which allows a shorter length of Ge to be used resulting in higher speed due to lower effective capacitance and shorter transit time for the carriers".

• Resulting Obvious Invention: An epitaxially grown Ge-on-Si avalanche photodiode, similar to that disclosed by Kang et al., where the germanium absorption layer incorporates microstructured pillars or holes to enhance absorption, thereby enabling higher quantum efficiency at 1310 nm (or other long wavelengths) and/or allowing for a thinner Ge layer for increased bandwidth.

3. Incorporating Voids for Refractive Index Modification and Capacitance Reduction

• Prior Art (General Knowledge and Patent's own statements about prior understanding):

  • The patent explicitly states that "microstructures such as voids are used to reduce effective refractive index to create resonant structures to enhance the absorption".
  • It also describes that "structures such as voids, air gaps, and/or holes... have dimensions on the order of the optical wavelength, the optical electromagnetic field will see an average refractive index... referred to herein as the effective refractive index".
  • Furthermore, the patent discusses prior concepts such as "a glass material in which the glass has a plurality of buried voids dimensioned between 0.01 microns to 1000 microns", and a "microwave transmission line structure" with "high-density dielectric-filled voids configured to reduce a dielectric constant of the semiconductor substrate material". An "optical waveguide structure" is also mentioned where a "supporting material includes a plurality of microstructured voids that are configured to alter an effective index of refraction".
  • The patent notes that High Contrast Gratings (HCG) effects, including resonance effects, are generally known (referencing "Chang-Hasnain").

• Motivation for Combination:
  A PHOSITA designing photosensitive devices would understand that optical absorption can be enhanced through resonant structures that control the effective refractive index and optical path. The concept of using voids to modify the effective refractive index of a material and to reduce its dielectric constant (and thus capacitance) is explicitly recognized as known in various technical fields, as indicated by the patent's own background description. Given the desire to enhance absorption (e.g., through resonant HCG structures) and simultaneously reduce device capacitance (to improve high-frequency performance by lowering the RC time constant), it would be an obvious step to incorporate voids into the semiconductor absorption region of a photodetector. The PHOSITA would be motivated to exploit the known effects of voids to achieve these dual benefits.

• Resulting Obvious Invention: A photosensitive device (PD, APD, PV) where the semiconductor absorption region contains a plurality of microstructured voids. These voids would be configured (sized, shaped, density) to reduce the effective refractive index of the region, facilitating resonant absorption enhancement (e.g., by creating HCG effects), and simultaneously reducing the effective capacitance of the device for improved high-frequency operation due to a lower RC time constant.

In summary, while the specific claims are unavailable, the core inventive concepts of US12243948, relating to using microstructures (pillars, holes, voids) to enhance absorption and reduce capacitance in high-speed photosensitive devices across various material systems, appear to be rendered obvious by combining existing knowledge and explicit prior art references, particularly those demonstrating light trapping in similar material systems and the use of voids to modify optical and electrical properties. The motivation for such combinations stems from well-recognized problems in achieving high-performance photosensitive devices.