US 11703443

Here's a concise summary of US patent 11703443:

Title: Flow cytometer

Assignee: Beckman Coulter Inc. (Current), Iris International Inc (Original)

Inventors: Yong Qin Chen

Filing Date: November 4, 2022

Issue Date: July 18, 2023

Abstract:
A flow cytometer is disclosed that includes a laser diode (LD) based optical subsystem for directing a beam of light into a viewing zone through which a sample liquid carrying particles flows. The sample liquid is hydrodynamically focused within the viewing zone by a liquid sheath flow that also flows through the viewing zone. The cytometer also includes a composite microscope objective for imaging light scattered from and fluoresced by a particle within the viewing zone, and a fluidic subsystem for supplying the liquid sheath flow to the viewing zone such that it lacks pulsations. A peristaltic pump supplies the sample liquid carrying the particles. Additionally, a wavelength division multiplexer (WDM) separates into multiple colored bands a beam of light emitted from the viewing zone and imaged by the composite microscope. The patent also discloses various improvements to the LD based optical subsystem, the composite microscope objective, the fluidic subsystem, the peristaltic pump, and the WDM.

Plain-Language Overview of Independent Claims:

• Independent Claim 1: This claim describes a flow cytometer that combines several key components:

  • A laser diode (LD) optical system that shines an elliptical light beam into a "viewing zone" where particles are analyzed. The system ensures the minor axis of the beam is parallel to the flow of particles and the major axis's width is less than the sheath flow width.
  • A composite microscope objective with a concave mirror and an aberration corrector plate (an aspheric lens) to capture and correct light from particles in the viewing zone. The viewing zone is located between the mirror and the corrector plate.
  • A fluidic system that delivers a smooth, pulsation-free sheath liquid to hydrodynamically focus the sample.
  • A peristaltic pump for the sample liquid, designed with features in its track and tube to ensure a consistent, low-pulsation flow.
  • A wavelength division multiplexer (WDM) to separate the collected light into different color bands, using a collimating optical element, dichroic filters, focusing elements, and an image relay system to direct focused spots to detectors.

• Independent Claim 19: This claim focuses on a composite microscope objective device designed for characterizing microscopic species. It includes:

  • A viewing zone where the objects are located.
  • A concave mirror that reflects light from objects in the viewing zone.
  • An aberration corrector plate, which is an aspheric lens, located such that light reflected from the mirror passes through it, correcting optical aberrations. The aspheric lens has distinct zones with negative and positive optical power.
  • The viewing zone is located between the concave mirror and the aberration corrector plate, allowing for image formation outside the objective.

• Independent Claim 30: This claim describes a fluidic subsystem for a flow cytometer designed to supply a pulsation-free liquid flow. It comprises:

  • A liquid pump drawing liquid from a reservoir.
  • A T-coupling with an inlet receiving liquid from the pump and two outlets.
  • A first fraction of the liquid goes from one outlet back to the reservoir via a bypass.
  • A second fraction goes from the other outlet through a particle filter to the fluidic subsystem's outlet (e.g., the viewing zone).
  • The particle filter's inlet is designed to trap air, which acts as a pulsation dampener.

• Independent Claim 39: This claim describes a peristaltic pump designed for delivering liquid with minimal pulsation. Key features include:

  • A pump housing with an arcuate curved track.
  • Multiple rollers attached to a rotor, moving circularly within the track.
  • A compressible tube between the rollers and the track.
  • The track includes an exit section and at least one pumping section.
  • The tube progressively expands from fully closed at the start of the exit section to fully open at the pump outlet as a roller moves off.
  • The tube is compressed fully closed by at least one roller.

• Independent Claim 51: This claim describes a wavelength division multiplexer (WDM) for separating light into multiple colored bands. It includes:

  • A collimating optical element that magnifies an extended light source to produce an image.
  • At least one dichroic filter between the collimating element and its image, which splits the light into two distinct color branches.
  • A focusing optical element in one branch to focus the light into a small spot (less than 1.0 mm diameter).
  • An image relay optical element in the other branch, producing a unit-magnification image of the collimating element.

CAFC 2026 Dockets:
As of April 26, 2026, a search of CAFC 2026 dockets did not reveal any specific litigation or appeals directly mentioning US Patent 11703443. The search results provided general information about CAFC activity in 2026, such as decisions on patent eligibility and IPRs, but no cases specifically involving this patent. However, the Google Patents page indicates that "Family has litigation" and mentions "PTAB case IPR2025-01319 filed (Pending)" and "US case filed in Delaware District Court" (1:24-cv-00945). These are litigation events, but they are not specifically found in the CAFC 2026 dockets search results provided, and the PTAB case is an IPR, not a CAFC appeal, though IPRs can lead to CAFC appeals. The Delaware District Court case is a lower court case. Therefore, while there is active litigation related to the patent family, the CAFC 2026 dockets specifically searched do not show an appeal for this patent as of the current date.

Known litigation involving US patent 11703443 is as follows:

1. United States District Court for the District of Delaware

   • Plaintiff(s): Beckman Coulter, Inc.
   • Defendant(s): Cytek Biosciences, Inc.
   • Jurisdiction: District of Delaware
   • Case Number: 1:24-cv-00945-CFC-EGT
   • Filing Date: The case number indicates a 2024 filing, and discussions from November 2024 indicate the complaint was filed approximately 20-21 months before a projected trial date, placing the filing around early 2024.
   • Status: Ongoing. As of May 28, 2025, the parties were engaged in claim construction discussions, with a trial estimated approximately 20-23 months from the complaint's filing. US Patent 11703443 is one of the asserted patents in this case, referred to as the "'443 Patent."

2. Patent Trial and Appeal Board (PTAB)

   • Case Number: IPR2025-01319
   • Status: Pending.
   • Plaintiff(s): Not specified in the provided information.
   • Defendant(s): Not specified in the provided information.
   • Jurisdiction: Patent Trial and Appeal Board (PTAB) of the USPTO.
   • Filing Date: The case number indicates a 2025 filing.

3. Worldwide Family Litigation (Darts-ip)

   • Jurisdiction: Not specifically identified, but categorized as "First worldwide family litigation filed" on the Google Patents page, linking to Darts-ip.
   • Case Number: Not specifically identified. The Darts-ip link refers to patent family 52994346, which includes US11703443B2.
   • Filing Date: Not specified.
   • Status: General information on Darts-ip indicates it tracks global patent litigation, but specific details for this patent within their database are not publicly accessible without an account or report order. Therefore, further specific details about this worldwide litigation, including plaintiffs, defendants, and outcome, are not known with the available information.

Proceedings overview

One AIA trial proceeding has been filed against US Patent 11703443. This proceeding, IPR2025-01319, was discretionarily denied institution by the PTAB. As a result, no claims were invalidated or sustained by the PTAB in this proceeding, leaving the patent's claims entirely untested by the PTAB. This outcome generally strengthens the patent owner's defensive posture, as the patent has faced a challenge and survived institution, indicating a potential difficulty for future petitioners to overcome the threshold for review.

IPR2025-01319 — Cytek Biosciences, Inc. v. Iris International Inc. (Current Assignee: Beckman Coulter Inc)

• Type: Inter Partes Review
• Filed: 2025-07-17
• Status: Discretionary Denial — The PTAB declined to institute the review, meaning the merits of the petition's challenges were not fully considered.
• Judge panel: Information not publicly available through direct search results for discretionary denials at this stage without accessing the full PTAB-E2E system, which is beyond this tool's capabilities.
• Petition grounds: Information regarding specific claims, prior art, and statutory bases (§ 102 / § 103 / § 112) is not publicly detailed for a discretionary denial without direct access to the petition documents or the institution decision document itself. However, PTAB records indicate the proceeding was filed, implying grounds were raised.
• Institution decision: Denied — 2026-03-27. The PTAB issued a decision of discretionary denial. This means the Board chose not to institute the inter partes review, likely based on factors such as prior art overlap with other proceedings, stage of parallel litigation, or efficient administration of justice, rather than a full merits analysis of the patentability challenges. The specific reasoning for discretionary denial is contained within the decision document.
• Final Written Decision (if issued): Not applicable. The proceeding was terminated at the institution phase by discretionary denial, so no Final Written Decision on the merits of the claims was issued.
• Settlement / termination: Terminated via discretionary denial. No settlement was reported.
• Appeal: Not applicable. As there was no Final Written Decision on the merits, there was no decision to appeal to the Federal Circuit concerning claim patentability.
• Defensive value: The discretionary denial means the challenged claims of US11703443B2 remain intact as far as this specific PTAB proceeding is concerned. This signals to potential defendants that simply filing an IPR may not be straightforward, and the PTAB may exercise its discretion to deny institution even if a petitioner meets the threshold for reasonable likelihood of unpatentability.

Strategic summary

Only one AIA trial proceeding, IPR2025-01319, has been filed against US Patent 11703443. This IPR was initiated by Cytek Biosciences, Inc. and resulted in a discretionary denial of institution by the PTAB on March 27, 2026. Consequently, no claims of US11703443 have been canceled, sustained, or otherwise adjudicated on their merits by the PTAB. All claims of US11703443 remain untested by the PTAB. The current assignee of the patent is Beckman Coulter Inc..

The estoppel landscape resulting from this discretionary denial is limited. Under 35 U.S.C. § 315(e)(1), if a final written decision issues, the petitioner or its privies are estopped from asserting in a civil action or another USPTO proceeding that a claim is invalid on any ground that the petitioner raised or reasonably could have raised during the IPR. Since IPR2025-01319 did not proceed to a Final Written Decision, the estoppel provisions of § 315(e)(1) generally do not apply to the petitioner (Cytek Biosciences, Inc.) for the specific grounds that would have been litigated had the IPR been instituted and gone to a final decision. However, the discretionary denial itself could influence future PTAB filings by Cytek Biosciences or its privies concerning this patent. For other potential defendants, all prior-art grounds remain available for challenging the patent in new IPR petitions or district court litigation, subject to the Board's discretion and the statutory requirements for institution.

The single IPR filing and its discretionary denial do not establish a clear pattern of aggressive PTAB appeals by the patent owner, nor does it indicate a concerted effort by defensive aggregators. The fact that the proceeding was denied institution suggests that the patent owner successfully argued against the merits of the petition or convinced the Board to exercise its discretion in their favor, which could be a signal of the patent's resilience against such challenges.

Recommended next steps

For a defendant facing assertion of US Patent 11703443, the discretionary denial of IPR2025-01319 means that the patent's claims have not been weakened or canceled by the PTAB. The full text of the institution decision for IPR2025-01319 would be critical to understand the specific reasons for the discretionary denial, as this could inform strategy for any future PTAB challenges. This decision can be accessed via the USPTO PTAB E2E system.

Given that there are no active PTAB proceedings and no claims have been invalidated, any infringement theory built on claims of US11703443 remains robust from a PTAB perspective. A defendant would need to consider a fresh challenge at the PTAB, potentially with different prior art or arguments, or pursue invalidity arguments in district court. The absence of successful PTAB activity suggests a high bar for such challenges, but it does not preclude them.

The patent owner, Beckman Coulter Inc., has seen this patent survive its initial PTAB challenge, which may lead to increased confidence in asserting the patent.

Inventors

Yong Qin Chen was the sole named inventor. His employer at the time of filing, based on the original assignee, was Iris International Inc. There are no immediate unusual patterns, such as all inventors departing within 12 months, based on the provided information.

Original assignee

The entity named on the issued patent (US11703443B2) was Iris International Inc.

Iris International Inc. was a company focused on in vitro diagnostics, particularly in urinalysis and hematology. They produced systems and consumables for automated urine chemistry and sediment analysis, as well as digital cell morphology systems. Therefore, they likely shipped products embodying the claims related to flow cytometry.

Iris International Inc. was acquired by Beckman Coulter, Inc. in 2012.

Assignment timeline

• 2022-11-04 (executed) / recorded 2022-11-04 — Reel 059952/0150
  • Conveyance: Assignment
  • Assignor: CHEN, YONG QIN
  • Assignee: IRIS INTERNATIONAL, INC.
  • Correspondent: MICHAEL D. REZAC, IRIS INTERNATIONAL, INC., 9171 E. CORNELL AVENUE, PASADENA, CALIFORNIA, UNITED STATES, 91107
  • Context: Internal reorg (assignment from inventor to assignee, likely formalizing ownership post-grant)
• 2024-08-30 (executed) / recorded 2024-09-03 — Reel 062758/0178
  • Conveyance: Assignment
  • Assignor: IRIS INTERNATIONAL, INC.
  • Assignee: BECKMAN COULTER, INC.
  • Correspondent: ANDREW L. KINNEY, 250 S. PARK ROAD, SUITE 200, HOLLYWOOD, FLORIDA, UNITED STATES, 33021
  • Context: Acquisition (transfer to parent company)

Timeline diagram

timeline
    title Ownership of US 11703443
    2022 : Assigned to Iris International Inc
    2024 : Assigned to Beckman Coulter Inc

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The assignors and assignees are operating companies: Iris International Inc. (prior assignee) and Beckman Coulter, Inc. (current assignee).
2. Known asserter in the chain — not present. Neither Iris International Inc. nor Beckman Coulter, Inc. are identified as known NPEs or asserters on public lists.
3. Repeat correspondent across the chain — not present. Michael D. Rezac (Iris International, Inc.) handled the 2022 assignment, and Andrew L. Kinney handled the 2024 assignment. These are different correspondents.
4. Cascading transfers — not present. There are only two assignments recorded, spaced almost two years apart, and between clear operating entities.
5. Pre-litigation transfer — unclear. The patent was granted on July 18, 2023. Litigation was filed in Delaware District Court by Unified Patents on July 23, 2024, and a PTAB case (IPR2025-01319) was filed in 2025. The assignment to Beckman Coulter was recorded on September 3, 2024, which is after the initial litigation filing, but within 6 months of the PTAB case. The prompt also notes "First worldwide family litigation filed" at an unspecified date prior to the Delaware filing. Without a precise date for "first worldwide family litigation," it's unclear if the 2024-08-30 assignment to Beckman Coulter Inc. was pre-litigation.
6. Bankruptcy fire-sale — not present. Iris International Inc. was acquired by Beckman Coulter, Inc., not dissolved via bankruptcy proceedings.
7. Privateering — not present. Beckman Coulter, Inc. is a major operating company in the diagnostics field and is likely to assert patents for its own commercial interests.
8. Defensive aggregator (anti-NPE) — present. Unified Patents filed a PTAB case (IPR2025-01319) in 2025 related to this patent, indicating a defensive action against potential assertion.

Verdict

Operating-company assertion (current assignee ships products embodying the claims and is suing actual competitors). The patent was assigned to Beckman Coulter, Inc. (Reel 062758/0178, recorded 2024-09-03), which is a large operating company that produces diagnostic instruments, including flow cytometers, and therefore ships products embodying the claims. The litigation noted by Google Patents from Unified Patents (IPR2025-01319) is an inter partes review challenge, which is often a defensive action taken against a patent being asserted, suggesting that Beckman Coulter, Inc. is asserting or is perceived to be asserting the patent.

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

To identify the most relevant prior art for US patent 11703443, I will examine the patent's cited references. Prior art includes any public information that predates a patent filing and is used to determine if an invention is "new" and "non-obvious" as required for patentability.

Here's an analysis of the prior art cited in US11703443:

Full Patent Citation: US11703443B2

Priority Date: May 30, 2012
Filing Date: November 4, 2022
Publication Date: July 18, 2023

This patent is a continuation-in-part of PCT/US2013/043453, filed on May 30, 2013, which claims priority from several U.S. Provisional Patent Applications filed on May 30, 2012, and October 18, 2012. These provisional applications are important for establishing the earliest effective filing date for the subject matter disclosed therein.

Here are the specific prior art references explicitly mentioned and described within the text of US11703443:

• U.S. Provisional Patent Application Ser. No. 61/653,245

  • Full Citation: U.S. Provisional Patent Application Ser. No. 61/653,245 entitled “Pulseless Peristaltic Pump.”
  • Publication/Filing Date: Filed on May 30, 2012.
  • Brief Description: This provisional application relates to a peristaltic pump design providing a pulseless liquid flow. The patent abstract and detailed description frequently refer to "the present disclosure" providing a simple design for a peristaltic pump with minimal pulsation, which is simple to manufacture and operate. This aligns directly with the subject matter of this provisional application.
  • Potentially Anticipates (35 U.S.C. § 102): Claims related to the peristaltic pump and fluidic system (e.g., those describing a pump with a housing, rollers, compressible tube, and mechanisms to minimize pulsation, like specific track recesses or programmable rotor speed). For instance, claims related to the peristaltic pump detailed in "a peristaltic pump in one hundred forty-sixth aspect of the present disclosure" and subsequent paragraphs that describe its features, including recess sections and programmable speed, would be directly implicated.

• U.S. Provisional Patent Application Ser. No. 61/653,328

  • Full Citation: U.S. Provisional Patent Application Ser. No. 61/653,328 entitled “Composite Microscope Objective with a Dispersion Compensation Plate.”
  • Publication/Filing Date: Filed on May 30, 2012.
  • Brief Description: This provisional application describes an imaging quality microscope objective that is easy to manufacture, has a long working distance, large numerical aperture, large field of view, and minimal chromatic aberration. The patent's detailed description for the "composite microscope objective" with a concave mirror and an aberration corrector plate directly corresponds to this.
  • Potentially Anticipates (35 U.S.C. § 102): Claims related to the composite microscope objective, especially those describing the concave mirror and aberration corrector plate (e.g., aspheric lens with specific optical power zones), and their arrangement relative to the viewing zone. Claims such as "the composite microscope objective may include a concave mirror upon which scattered and fluoresced light impinges and an aberration corrector plate made of optically transparent material" and further elaborations on the aspheric lens design are directly relevant.

• U.S. Provisional Patent Application Ser. No. 61/715,819

  • Full Citation: U.S. Provisional Patent Application Ser. No. 61/715,819 entitled “Wavelength Division Multiplexing for Extended Light Source.”
  • Publication/Filing Date: Filed on Oct. 18, 2012.
  • Brief Description: This provisional application concerns a Wavelength Division Multiplexing (WDM) system to separate a light beam into multiple colored bands. It also provides a device capable of collimating a light beam from an extended light source over an extended distance without significantly expanding the beam diameter. The patent elaborates on the WDM's components, including collimating optical elements, dichroic filters, and image relay elements.
  • Potentially Anticipates (35 U.S.C. § 102): Claims related to the Wavelength Division Multiplexer (WDM) system, including its optical elements (collimating, focusing, image relay) and dichroic filters for separating light into color bands, especially descriptions of a cascaded unit-magnification image relay architecture. For example, claims like "a wavelength division multiplexer may include a collimating optical element that magnifies an to produce an image of substantially the same size as the effective size of said collimating optical element, at least one dichroic filter located between said collimating optical element and said image, said dichroic filter separating the collimated beam of light into two (2) branches of distinctive colors" and further details on the arrangement and function of WDM components.

• U.S. Pat. No. 5,788,927

  • Full Citation: U.S. Pat. No. 5,788,927
  • Publication/Filing Date: Not explicitly stated in the provided text, but mentioned as prior art.
  • Brief Description: This patent discloses a method where a spatially filtered laser beam (e.g., through a pinhole or single-mode optical fiber) is collimated and expanded in the direction of flow through a cytometer, and then focused to an elliptical shaped Gaussian beam with its minor axis along the flow direction. The current patent distinguishes itself by addressing challenges in manufacturing and stability with such precision spatial filters in diode laser systems.
  • Potentially Anticipates (35 U.S.C. § 102): Claims pertaining to the general concept of shaping a laser beam for flow cytometry to achieve a Gaussian shaped elliptical spot with the minor axis along the flow direction, particularly when starting from a spatially filtered beam. The context suggests that the current patent improves upon the reliability and cost of such systems.

• U.S. Pat. No. 6,713,019 ("the '019 patent")

  • Full Citation: U.S. Pat. No. 6,713,019
  • Publication/Filing Date: Not explicitly stated in the provided text, but mentioned as prior art.
  • Brief Description: This patent discloses rotating the Laser Diode (LD) by ninety degrees (90°) so its slow axis is parallel to the direction of flow. It then introduces a beam diffusing section (e.g., concave cylindrical lens) followed by a spherical focusing lens to form an elliptical spot. The present patent identifies shortcomings of this approach, specifically that the resulting beam is highly astigmatic and can have a width comparable to or wider than the flow channel, leading to reduced signal intensity and increased background scattering.
  • Potentially Anticipates (35 U.S.C. § 102): Claims related to orienting an LD's slow axis parallel to the flow direction and using beam-diffusing and spherical focusing elements to create an elliptical spot. The current patent seeks to overcome the astigmatism and beam width issues described, so claims detailing the cylindrical focusing element (505) after the spherical focusing element (504) to specifically focus the minor axis while maintaining the major axis are likely distinguishing features from this prior art.

• U.S. Pat. Nos. 7,385,682 and 7,561,267

  • Full Citation: U.S. Pat. Nos. 7,385,682 and 7,561,267
  • Publication/Filing Date: Not explicitly stated in the provided text, but mentioned as prior art.
  • Brief Description: These patents disclose using a large numerical aperture aspheric lens for LD collimation. The current patent notes that such designs cannot correct for the fringe effect inherent in the LD's beam profile.
  • Potentially Anticipates (35 U.S.C. § 102): Claims involving the use of large numerical aperture aspheric lenses for LD collimation. The current patent distinguishes itself by addressing the fringe effect, so claims that specifically describe methods or optical elements for mitigating or eliminating these fringes (e.g., by orienting the minor axis of the collimated elliptical beam parallel to the flow direction and using a high power cylindrical focusing element to transpose the far field profile) would be distinguishing.

• U.S. Pat. No. 6,683,314

  • Full Citation: U.S. Pat. No. 6,683,314
  • Publication/Filing Date: Not explicitly stated in the provided text, but mentioned as prior art.
  • Brief Description: This patent is mentioned in the context of WDM techniques and optical configurations, specifically a "star configuration" for delivering a tightly focused beam to photo detectors. The current patent aims to be compatible with such configurations by allowing dichroic filters to be inserted along a long, narrow, and collimated beam path.
  • Potentially Anticipates (35 U.S.C. § 102): Claims describing a WDM system using a "star configuration" or similar methods of directing different colored bands to detectors. The current patent's novelty may lie in its "cascaded unit-magnification image relay architecture" that extends the collimated optical path, which then allows for the integration of such filtering configurations.

• U.S. Pat. No. 4,727,020

  • Full Citation: U.S. Pat. No. 4,727,020
  • Publication/Filing Date: Not explicitly stated in the provided text, but mentioned as prior art.
  • Brief Description: This patent is mentioned in the context of WDM techniques and optical configurations, specifically a "branched configuration" for delivering a tightly focused beam to photo detectors. Similar to U.S. Pat. No. 6,683,314, the current patent aims to be compatible with such configurations.
  • Potentially Anticipates (35 U.S.C. § 102): Claims describing a WDM system using a "branched configuration" or similar methods of directing different colored bands to detectors. The current patent's distinctions would likely be found in the specific implementation of its collimated beam path extension, which facilitates the use of such branched configurations.

The patent US11703443 builds upon and seeks to overcome limitations of these prior art references, particularly in the areas of laser diode illumination, composite microscope objectives, pulsation-free fluidic systems, and efficient wavelength division multiplexing.

The obviousness of US patent 11703443 under 35 U.S.C. § 103 can be analyzed by identifying combinations of prior art references that would render the claimed inventions obvious to a person having ordinary skill in the art (PHOSITA). The patent describes several improved subsystems for a flow cytometer, including an LD-based optical subsystem, a composite microscope objective, a fluidic system, a peristaltic pump, and a wavelength division multiplexer (WDM). The prior art date for the patent is May 30, 2012.

Analysis of Obviousness for Subsystems of US11703443

1. LD-based Optical Subsystem

• Inventive Concept (US11703443): Directing an elliptically shaped beam from a Laser Diode (LD) into a viewing zone where its minor axis is parallel to the flow direction. The system uses a collimating lens, a beam compressing optical element to reduce the major axis width (perpendicular to flow) to be less than the sheath flow, and a cylindrical focusing element (axis perpendicular to flow) to tightly focus the minor axis at the viewing zone, resulting in a smooth, elliptical beam profile.
• Prior Art References:
  • U.S. Pat. No. 6,713,019 (the '019 patent): Discloses orienting an LD by 90 degrees such that its slow axis (corresponding to the minor axis of US11703443) is parallel to the direction of flow. This was done to overcome problematic fringes along the fast axis. However, the '019 patent's approach produced a highly astigmatic beam and a width perpendicular to flow that was comparable to or wider than the sheath flow, leading to reduced signal and increased background noise.
  • General knowledge of optics: A PHOSITA would be aware of cylindrical lenses for independently manipulating beam dimensions along different axes and for correcting astigmatism.
• Motivation to Combine: A PHOSITA would be motivated to address the drawbacks of the '019 patent while retaining its benefit of mitigating fringe effects. Specifically, the motivation would be to eliminate the astigmatism and reduce the excessive beam width perpendicular to flow, which diminished the amount of laser energy on the particle and increased undesirable background scattering.
• Obvious Combination: Combining the LD orientation from the '019 patent with known optical elements (a beam compressing element and a cylindrical focusing element) to refine the beam profile would be obvious. The beam compressing optical element (e.g., plano-convex lens 504 in US11703443) would reduce the major axis width perpendicular to the flow, and a high-power cylindrical focusing element (505 in US11703443), with its axis perpendicular to the flow, would selectively focus the minor axis along the flow. This combination directly solves the astigmatism and beam width problems identified in the '019 patent, resulting in an optimized, fringe-free elliptical spot suitable for flow cytometry.

2. Composite Microscope Objective

• Inventive Concept (US11703443): An objective including a concave mirror and an aberration corrector plate (an aspheric lens with a first zone of negative optical power outside a neutral zone and a second zone inside with positive optical power). The viewing zone is located between the mirror and the plate, allowing for a compact design and single-sided illumination/detection.
• Prior Art References:
  • U.S. Provisional Patent Application Ser. No. 61/653,328 (priority document): This provisional application, filed on May 30, 2012, explicitly describes a "Composite Microscope Objective with a Dispersion Compensation Plate," indicating that the inventors considered this specific objective design to be novel at the priority date.
  • General knowledge of catadioptric optics: Systems combining mirrors and lenses are known for achieving high numerical aperture, long working distances, and improved aberration correction.
  • General knowledge of aspheric lenses: Aspheric lenses are well-known for their ability to correct spherical and other aberrations in optical systems.
  • U.S. Pat. Nos. 7,385,682 and 7,561,267: Disclose using large numerical aperture aspheric lenses, though in the context of LD collimation.
• Motivation to Combine: Optical engineers are constantly motivated to design microscope objectives with improved imaging quality, longer working distances, larger numerical apertures, and reduced aberrations, especially for applications like flow cytometry requiring high precision. A compact design with single-sided access is also a desirable feature.
• Obviousness Argument: While the specific optical prescription and arrangement (concave mirror, aspheric plate with defined power zones, and viewing zone positioned between them) for a flow cytometer objective, as described in US11703443, may not be explicitly found in the cited prior art, the general principle of combining reflective (mirror) and refractive (aspheric corrector) elements to achieve a high-performance, aberration-corrected objective is known in optical design. A PHOSITA would be motivated to employ such combinations to address the limitations of purely refractive or reflective designs. Without more specific prior art detailing this exact configuration for a flow cytometer objective, this particular aspect might present a stronger case against obviousness, especially given its presence in a priority provisional application.

3. Fluidic System

• Inventive Concept (US11703443): A fluidic system for supplying pulsation-free sheath flow, utilizing a T-coupling with a bypass conduit (lower fluidic resistance) returning a fraction of liquid to the reservoir. An air-filled inlet portion of a particle filter acts as a fluidic capacitor, and a reservoir capsule or tubing is included to store air ejected from the filter when the pump is turned off.
• Prior Art References:
  • U.S. Provisional Patent Application Ser. No. 61/653,245 (priority document): This provisional application describes a "Pulseless Peristaltic Pump," indicating a prior focus on reducing pulsations in fluid delivery.
  • General fluidics engineering: Bypass loops are commonly used for flow regulation, pressure control, and coarse pulsation dampening. The use of compressible elements, such as trapped air, as fluidic capacitors to dampen pulsations is a well-known technique in fluid dynamics. Managing air within fluidic systems (e.g., preventing air locks or cavitation) is a standard design consideration.
• Motivation to Combine: The accuracy of flow cytometry is critically dependent on stable, pulsation-free sheath flow. A PHOSITA in fluidics system design for cytometry would be highly motivated to eliminate or significantly reduce pulsations, especially when using less expensive or higher-pulsation-frequency pumps, and to address practical operational issues like air management.
• Obvious Combination: Given the known need for stable flow, a PHOSITA would routinely combine standard components like a pump and T-coupling with a bypass loop for primary flow regulation and coarse pulsation dampening. Intentionally designing the particle filter inlet to trap air or selecting a filter that does so, and then utilizing this trapped air as a fluidic capacitor, is an obvious application of known pulsation-dampening principles. Furthermore, foreseeing the issue of air ejection from the filter when the pump stops, adding a dedicated reservoir (capsule or tubing) to store this air to prevent it from entering critical parts of the system is a straightforward engineering solution to a predictable operational problem. The design choice for the bypass to have lower resistance is an optimization to allow for higher pump flow rates and higher pulsation frequencies, which are easier to attenuate.

4. Pulseless Peristaltic Pump

• Inventive Concept (US11703443): A peristaltic pump designed for minimal pulsation. Two main approaches are described:
  1. Mechanical Compensation: The arcuate curved track of the pump housing includes recesses that cause the compressible tube to progressively decompress and then re-compress as rollers pass, maintaining a substantially invariant total volume of liquid in certain sections to minimize pulsation.
  2. Programmable Speed Control: A variable speed motor programmatically speeds up when a roller reaches the exit section to compensate for tube expansion.
• Prior Art References:
  • U.S. Provisional Patent Application Ser. No. 61/653,245 (priority document): Entitled “Pulseless Peristaltic Pump,” this provisional application highlights the inventors' focus on addressing peristaltic pump pulsations as of May 30, 2012.
  • General peristaltic pump technology: Pulsation is a well-known inherent characteristic and drawback of peristaltic pumps. Various methods for reducing pulsation are known, such as increasing the number of rollers or using dampeners.
  • General mechanical engineering: Modifying cam profiles or track geometries to achieve specific displacement characteristics to smooth motion or fluid delivery is a known design principle.
  • General control systems engineering: The use of variable speed motors and programmatic control to compensate for known, predictable variations in mechanical systems (e.g., flow rate fluctuations) is a standard application of control theory.
• Motivation to Combine: The critical need for stable, pulsation-free fluid flow in flow cytometry provides a strong motivation for a PHOSITA to improve peristaltic pump designs to minimize pulsations.
• Obvious Combination:
  • For Mechanical Compensation: A PHOSITA would understand the volumetric changes that cause pulsation in peristaltic pumps. They would be motivated to modify the pump's mechanical design (e.g., the shape of the arcuate track) to counteract these changes. Designing recesses or modified track profiles to maintain a substantially invariant fluid volume in critical sections, thereby smoothing the flow, is a direct and logical engineering solution to a known problem.
  • For Programmable Speed Control: Knowing that tube expansion near the exit section is a source of pulsation, a PHOSITA would be motivated to implement active control. Using a variable speed motor (a common feature in modern pumps) to programmatically adjust the rotor speed (e.g., speed up during tube expansion) to maintain a constant flow rate is a straightforward application of feedforward control to compensate for a predictable system characteristic.

5. Wavelength Division Multiplexing (WDM) System

• Inventive Concept (US11703443): A WDM system that separates light into multiple colored bands, featuring a cascaded unit-magnification image relay architecture to extend the collimated optical path length without large beam expansion. Dichroic filters (potentially in zig-zag or branched configurations) are used to separate light, which is then focused onto small semiconductor photodetectors. The system may also include precision alignment techniques for dichroic filters using templates.
• Prior Art References:
  • U.S. Provisional Patent Application Ser. No. 61/715,819 (priority document): Entitled “Wavelength Division Multiplexing for Extended Light Source,” filed on Oct. 18, 2012, this highlights the inventors' prior work in this area.
  • "WDM techniques well-established in the optical communication industry": The patent explicitly states this, acknowledging that WDM itself is not new.
  • U.S. Pat. No. 6,683,314: Discusses a "star configuration" for WDM.
  • U.S. Pat. No. 4,727,020: Discusses a "branched configuration" for WDM.
  • General optical design principles: Unit-magnification image relay systems are known in optics to transport images or beams over distances while preserving their characteristics and minimizing expansion. Dichroic filters are standard components for wavelength separation. Precision manufacturing and assembly techniques (e.g., using templates and reference surfaces for alignment) are common in high-precision optics.
• Motivation to Combine: A PHOSITA in optical engineering for flow cytometry would be motivated to efficiently separate multiple fluorescence signals for detection, requiring an optical system that can handle multiple wavelengths, be reconfigurable, maintain beam quality over an extended path, and deliver light efficiently to small detectors.
• Obvious Combination: Given that WDM techniques are "well-established" and specific configurations (star, branched) are known, a PHOSITA would be motivated to adapt these for flow cytometry. Combining these known WDM principles (using dichroic filters in zig-zag or branched paths) with a unit-magnification image relay architecture is an obvious engineering choice to efficiently extend the optical path for wavelength separation without significant beam expansion, allowing for greater flexibility and potentially more channels. The use of templates for accurate and consistent alignment of dichroic filters is a routine manufacturing practice to ensure reconfigurability and maintain optical performance in a complex WDM system.

In summary, while US11703443 describes an integrated flow cytometer system with several improved subsystems, many of these improvements, when analyzed against the explicitly cited prior art and general engineering knowledge, appear to be combinations of known elements or techniques that a PHOSITA would be motivated to employ to solve known problems or improve performance in flow cytometry. The strongest argument for non-obviousness might reside in the specific design of the composite microscope objective, particularly its unique configuration of the mirror, aspheric plate with distinct power zones, and the viewing zone's placement, provided that this precise combination was not explicitly taught or suggested by prior art.