DCT
3:19-cv-07470
Regents Of University Of Michigan v. Leica Microsystems Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: The Regents of the University of Michigan (Michigan)
- Defendant: Leica Microsystems Inc. (Delaware)
- Plaintiff’s Counsel: Feinberg Day Kramer Alberti Lim Tonkovich & Belloli LLP
- Case Identification: 3:19-cv-07470, N.D. Cal., 11/13/2019
- Venue Allegations: Venue is based on Defendant's alleged transaction of business in the district and its maintenance of a "regular and established place of business" in South San Francisco, California, which includes an imaging center that showcases the accused products.
- Core Dispute: Plaintiff alleges that Defendant’s white light laser confocal microscope systems infringe a patent related to methods for detecting fluorescence by separating excitation light from emission light in the time domain.
- Technical Context: The technology concerns fluorescence microscopy, a fundamental technique in biomedical research for observing tagged molecules in biological samples, where improving signal clarity and the ability to detect multiple targets simultaneously is critical.
- Key Procedural History: The complaint alleges that Defendant had knowledge of the patent-in-suit as early as April 2013 due to citations in its own patent prosecution. Plaintiff also alleges it provided direct notice of infringement to Defendant in June 2016 and again with claim charts in October 2017, but Defendant refused to take a license. Subsequent to the complaint filing, an Inter Partes Review (IPR) of the patent-in-suit was initiated (IPR2020-01165). In a decision reflected in a certificate issued October 25, 2023, the Patent Trial and Appeal Board (PTAB) found all claims (1-26) of the patent-in-suit to be patentable, a development which may substantially impact any invalidity defenses in this litigation.
Case Timeline
| Date | Event |
|---|---|
| 2005-02-18 | ’169 Patent Priority Date (Provisional Application) |
| 2007-10-02 | ’169 Patent Issue Date |
| 2013-04-19 | Date of Leica's PCT filing citing the '169 Patent publication, alleged as pre-suit knowledge |
| 2016-06-01 | Plaintiff alleges it first provided written notice of infringement to Defendant |
| 2017-10-19 | Plaintiff alleges it provided claim charts to Defendant |
| 2019-11-13 | Complaint Filing Date |
| 2020-06-26 | IPR2020-01165 Filed against the '169 Patent |
| 2023-10-25 | IPR Certificate Issued, confirming patentability of all claims |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,277,169 - "Whole Spectrum Fluorescence Detection With Ultrafast White Light Excitation," issued October 2, 2007
The Invention Explained
- Problem Addressed: The patent describes a fundamental challenge in fluorescence detection: separating the weak light emitted by a fluorescent sample (the signal) from the much stronger light used to excite it (the noise) (’169 Patent, col. 2:5-9). Conventional methods use optical filters, but this can be inefficient, block some of the desired signal, and limit the number of different fluorescent markers (fluorophores) that can be excited and detected at once (’169 Patent, col. 2:13-21, 2:28-35).
- The Patented Solution: The invention proposes using a very short ("ultrafast") pulse of broad-spectrum ("supercontinuum") white light to excite the sample. This excitation pulse is extremely brief (picoseconds or less), whereas the resulting fluorescence emission lasts much longer (nanoseconds) (’169 Patent, col. 3:28-34). The solution is to use a "time-resolving detector" that temporally distinguishes between the two events: it can be configured to ignore the initial, brief excitation pulse and only capture the subsequent, longer-lasting fluorescence signal, thereby separating signal from noise in the time domain rather than purely by wavelength (’169 Patent, Abstract; col. 3:34-40).
- Technical Importance: This time-domain separation allows for the detection of the entire fluorescence spectrum from multiple fluorophores simultaneously using a single light source, without the need for complex and costly sets of filters and mirrors common in prior art systems (’169 Patent, col. 4:54-60).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶26).
- The essential elements of independent claim 1 are:
- A fluorescence detection system for a sample with multiple fluorophores.
- A "single-source white light generation system" that outputs a "supercontinuum white light pulse" to excite the fluorophores.
- A "time-resolving detector" that receives both the fluorescence and a portion of the excitation pulse, and separates the fluorescence from that portion of the pulse.
- The complaint reserves the right to assert other claims (Compl. ¶43).
III. The Accused Instrumentality
Product Identification
The accused products are "each and every model of Leica's SP8 confocal microscope family that employs a white light laser," including the TCS SP8 X and TCS SP8 STED models (Compl. ¶25).
Functionality and Market Context
- The accused microscopes are high-end scientific instruments that use what Leica markets as an "innovative Leica White Light Laser" to excite fluorescent samples (Compl. ¶28). This laser is described as a "single device that produces a continuous spectral output between the wavelengths of 470 and 670 nanometers" (Compl. ¶28).
- A key accused feature is Leica’s "LightGate," which the complaint alleges is the claimed "time-resolving detector" (Compl. ¶21, ¶34). The LightGate is described in Leica's marketing materials as an "adjustable time gate [that] switches off the data collection during white light laser pulse" to remove unwanted signals and improve image contrast (Compl. ¶35). Leica promotional materials state this feature allows for the "filter-free method to quench unwanted signals" by excluding pulses of excitation light (Compl. ¶36, ¶38). The complaint provides a diagram from a Leica presentation illustrating how the "Adjustable LightGate window" is set to capture the "Fluorescence" signal while excluding the initial "Light reflected from cover glass" (Compl. ¶37, Ex. B, slide 44).
IV. Analysis of Infringement Allegations
'169 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A fluorescence detection system for testing a sample, said sample having a plurality of fluorophores... | The accused Leica SP8 microscope systems are fluorescence detection systems marketed for use with samples containing multiple fluorophores. | ¶27 | col. 7:43-45 |
| a single-source white light generation system outputting a supercontinuum white light pulse comprising an entire spectrum of white light, said supercontinuum white light pulse exciting the plurality of fluorophores of the sample to emit fluorescence... | The accused systems employ a "single device," the "innovative Leica White Light Laser," which produces a broad spectral output to excite any fluorophore. | ¶28, ¶30 | col. 7:46-50 |
| a time-resolving detector receiving said fluorescence and at least a portion of said supercontinuum white light pulse, said time-resolving detector separating said fluorescence from said portion of said supercontinuum white light pulse. | The accused systems' "LightGate" feature is an "adjustable time gate" that separates the desired fluorescence signal from the initial excitation light pulse by switching off data collection during the pulse, a form of temporal separation. | ¶34, ¶35, ¶37 | col. 7:51-55 |
Identified Points of Contention
- Scope Questions: A potential dispute may arise over whether Leica’s "White Light Laser," with an alleged output from "470 and 670 nanometers" (Compl. ¶28), meets the claim limitation of a "supercontinuum white light pulse comprising an entire spectrum of white light." The construction of "supercontinuum" and "entire spectrum" will be central to resolving this question.
- Technical Questions: The primary technical question is whether Leica’s "LightGate" technology, which functions as an on/off temporal gate, performs the function of the claimed "time-resolving detector... separating said fluorescence." The analysis will likely focus on whether this gating mechanism is technically and legally equivalent to the separation described in the patent, which provides a streak camera as an example embodiment (’169 Patent, col. 5:10-15).
V. Key Claim Terms for Construction
"time-resolving detector"
- Context and Importance: This term is the lynchpin of the infringement allegation. The case hinges on whether Leica's "LightGate" technology is properly classified as a "time-resolving detector" under the patent's claims. Practitioners may focus on this term because its construction will likely determine the outcome of the infringement analysis.
- Intrinsic Evidence for a Broader Interpretation: The claim language is functional, defining the detector by what it does: "receiving" both light signals and "separating" them. The patent specification explains this separation is possible because the excitation pulse duration is much less than the fluorescence lifetime, suggesting any device capable of exploiting this time difference could be covered (’169 Patent, col. 3:28-40).
- Intrinsic Evidence for a Narrower Interpretation: The patent’s detailed description uses a streak camera as a specific example of a time-resolving detector (’169 Patent, col. 5:10-15; Fig. 7). A party could argue that the term implies a device with similar capabilities to a streak camera, which resolves the temporal profile of a light signal, rather than a simpler mechanism that merely gates data collection on and off.
"supercontinuum white light pulse"
- Context and Importance: This term defines the type of light source required by the claim. The scope of this term is critical to determining whether the laser used in Leica's SP8 systems, as described in the complaint, meets this limitation.
- Intrinsic Evidence for a Broader Interpretation: The patent describes the desired output as having a "wide spectrum of light frequencies" enabling excitation of a "large variety of fluorophores" (’169 Patent, col. 3:56-57; col. 4:55-57). This could support an interpretation that covers any light source with a sufficiently broad and continuous spectrum for multi-fluorophore excitation.
- Intrinsic Evidence for a Narrower Interpretation: "Supercontinuum" is a technical term of art. A party could argue it requires a specific nonlinear optical generation process, such as the self-phase modulation described in the patent (’169 Patent, col. 3:49-51), or a spectral breadth exceeding that of the accused laser.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement based on Defendant’s marketing materials, manuals, and other instructions that allegedly direct customers to use the SP8 microscopes in an infringing manner (Compl. ¶40). It also alleges contributory infringement, asserting that the white light laser and "LightGate" functionalities are material, non-staple components especially adapted for infringement (Compl. ¶42).
- Willful Infringement: Willfulness is alleged based on Defendant’s purported knowledge of the ’169 Patent since at least April 2013, when its own patent application cited the ’169 Patent’s publication (Compl. ¶48). The allegation is further supported by claims of direct written notice from the Plaintiff in 2016 and 2017, followed by Defendant’s alleged refusal to take a license and continued sales (Compl. ¶41, ¶49-51).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of claim construction: can the term "time-resolving detector," exemplified in the patent by a streak camera, be construed to cover the "LightGate" technology in the accused products, which operates as an adjustable on/off time gate for data collection?
- A second central question will concern technical scope: does the accused "White Light Laser," with its specified spectral output, meet the claim requirement for a "supercontinuum white light pulse comprising an entire spectrum of white light" as that term would be understood by a person of ordinary skill in the art in view of the patent's disclosure?
- A key strategic question will be the impact of the IPR: how will the PTAB’s confirmation of the patentability of all claims of the ’169 Patent over a prior art challenge shape the litigation, particularly by limiting the invalidity arguments available to the Defendant in district court?