Prior art — US Patent 12174106

MEMORANDUM

To: File
From: Senior Patent Analyst
Date: May 13, 2026
Subject: Analysis of Prior Art for U.S. Patent No. 12,174,106

Introduction

This report provides an analysis of the prior art cited in U.S. Patent No. 12,174,106, titled "Flow cytometer," assigned to Beckman Coulter, Inc. The analysis examines each cited reference to determine its relevance and potential to anticipate the claims of the '106 patent under 35 U.S.C. § 102. The '106 patent discloses a flow cytometer system incorporating several improvements, including a laser diode (LD) based optical subsystem, a composite microscope objective, a pulsation-free fluidic subsystem, a specialized peristaltic pump, and a wavelength division multiplexer (WDM).

The claims of US 12,174,106 are directed towards these individual subsystems and their combination within a flow cytometer. Key aspects of the invention include:

A composite microscope objective featuring a concave mirror and an aspheric aberration corrector plate.
A fluidic system that uses a T-coupling and a bypass conduit to create a pulsation-free sheath flow.
A wavelength division multiplexer (WDM) designed with an imaging optical arrangement and a focusing optical element to be compatible with semiconductor photodetectors.
A peristaltic pump with a specially designed arcuate track and recess sections to minimize flow pulsation.
An LD-based optical system for creating an elliptical laser spot with a specific orientation and profile in the viewing zone.

Below is an evaluation of the most relevant prior art cited by the patent examiner during the prosecution of the '106 patent.

Analysis of Cited Prior Art References

Based on the file history of U.S. Patent No. 12,174,106, the following prior art references are considered most relevant.

1. U.S. Patent No. 4,818,103 A

Full Citation: US 4,818,103 A, "Flow cytometry," Inventor: Thomas, R., et al.
Publication Date: April 4, 1989
Filing Date: June 24, 1987
Brief Description: This patent describes a flow cytometer designed for simultaneous electronic and optical measurements of particles. It focuses on the geometry of the flow cell aperture to reduce electronic edge effects and improve sensitivity. The apparatus uses hydrodynamic focusing and can perform simultaneous optical and electronic measurements by incorporating optical elements into the aperture-defining structure.
Potential Anticipation of Claims: This reference is relevant to the general field of flow cytometry and the use of hydrodynamic focusing. However, it does not appear to anticipate the specific key features of the '106 patent.
- Composite Microscope Objective: The '103 patent does not disclose a composite microscope objective with a concave mirror and an aspheric aberration corrector plate as claimed in the '106 patent.
- Pulsation-Free Fluidics: While discussing fluidic systems, it does not detail a T-coupling with a bypass conduit for pulsation reduction.
- Specific Optical and WDM Systems: The optical system described is general and does not disclose the specific LD-based illumination system or the detailed WDM architecture of the '106 patent.

2. U.S. Patent No. 5,395,588 A

Full Citation: US 5,395,588 A, "Control of flow cytometer having vacuum fluidics," Inventors: North, Jr., H., et al.
Publication Date: March 7, 1995
Filing Date: August 12, 1993
Brief Description: This patent details a flow cytometer control system that utilizes a vacuum pump to draw sheath fluid through the flow cell. A flow restrictor creates a pressure drop to aspirate the sample into the sheath stream. The system is designed to control sample aspiration and includes methods for reverse-flushing to prevent carryover.
Potential Anticipation of Claims: The '588 patent is primarily concerned with a vacuum-driven fluidic system, which differs from the peristaltic pump-based system with a bypass for pulsation control claimed in the '106 patent.
- Fluidic Subsystem: The '588 patent's approach to fluid control is fundamentally different from the T-coupling and bypass system designed to dampen pulsations from a positive pressure pump as described in the '106 patent.
- Other Subsystems: This reference does not disclose the specific composite microscope objective, LD illumination system, or WDM structure of the '106 patent.

3. U.S. Patent No. 7,796,256 B2

Full Citation: US 7,796,256 B2, "High-NA flow chamber for imaging flow cytometry," Inventor: Ortyn, W., et al.
Publication Date: September 14, 2010
Filing Date: November 5, 2009
Brief Description: This patent discloses an imaging flow cytometer with a high numerical aperture (NA) objective, such as an oil-immersion objective, to improve imaging resolution and fluorescence collection efficiency. It addresses the limitations of prior art systems that used lower NA air objectives.
Potential Anticipation of Claims: This reference is relevant to the optical collection system of a flow cytometer but does not describe the specific objective design of the '106 patent.
- Composite Microscope Objective: While the '256 patent teaches the use of high-NA objectives, it does not disclose the claimed combination of a concave mirror and an aspheric aberration corrector plate with a viewing zone located between them. The solutions are different, with the '256 patent focusing on traditional, albeit high-NA, microscope objective designs.

4. U.S. Patent No. 7,842,244 B2

Full Citation: US 7,842,244 B2, "Flow cytometry for high throughput screening," Inventors: Dubrow, R., et al.
Publication Date: November 30, 2010
Filing Date: February 10, 2000
Brief Description: This patent describes a flow cytometry apparatus adapted for high-throughput screening of multiple samples. A key feature is the introduction of a separation gas (e.g., air bubbles) between samples in the fluid stream to prevent cross-contamination and allow for rapid, sequential analysis of discrete samples from multi-well plates.
Potential Anticipation of Claims: The '244 patent focuses on sample handling for high-throughput applications and does not address the core subsystem innovations of the '106 patent.
- Fluidic System: The fluidic system is designed for sample separation with gas bubbles, not for providing a pulsation-free sheath flow as claimed in the '106 patent.
- Optical and Pump Systems: It does not disclose the specific microscope objective, peristaltic pump design, or WDM configuration claimed in the '106 patent.

5. U.S. Patent No. 7,855,078 B2

Full Citation: US 7,855,078 B2, "High resolution flow cytometer," Inventor: Evans, K. M.
Publication Date: December 21, 2010
Filing Date: January 10, 2007
Brief Description: This patent relates to a high-resolution flow cytometer, particularly for particle differentiation and separation. It describes an enhanced resolution nozzle where a fluid source stream is introduced at an angle to improve particle resolution by the sensing system. The system is designed for applications like sperm sorting.
Potential Anticipation of Claims: The '078 patent's innovation lies in the design of the nozzle and fluid introduction to enhance resolution.
- Pulsation Control/Fluidics: While it concerns fluid dynamics within the nozzle, it does not teach the specific pulsation-dampening fluidic circuit with a T-coupling and bypass claimed in the '106 patent.
- Optical Systems: The optical system is not described in a way that would anticipate the detailed composite microscope objective or WDM structure of the '106 patent.

Conclusion

After a thorough review of the prior art cited during the examination of U.S. Patent No. 12,174,106, it is concluded that none of the individual references appear to anticipate the claimed inventions under 35 U.S.C. § 102. Each piece of prior art is directed to different aspects of flow cytometry technology. While they establish the state of the art in areas such as basic flow cell design, fluidic control for sample handling, and general optical objectives, they do not disclose the specific combinations of elements and unique designs that characterize the claims of the '106 patent. Specifically, the novel composite microscope objective, the pulsation-dampening fluidic system, the pulsation-minimizing peristaltic pump, and the reconfigurable WDM system, as claimed, are not taught by these references.