Mems Innovations LLC v. TDK Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: MEMS Innovations, LLC (Texas)
  • Defendant: TDK Corp (Japan); TDK CORPORATION OF AMERICA (California); Invensense, Inc. (Delaware)
  • Plaintiff's Counsel: One LLP
• Case Identification: 8:25-cv-02251, C.D. Cal., 10/06/2025
• Venue Allegations: Venue is alleged to be proper based on Defendants' business operations, employee presence, and commission of infringing acts within the judicial district. For TDK Corporation, an alien corporation, venue is asserted as proper in any district.
• Core Dispute: Plaintiff alleges that Defendants' ultrasonic sensors and piezoelectric microspeakers infringe two patents related to the design and manufacture of microelectromechanical systems (MEMS) acoustic devices.
• Technical Context: The lawsuit concerns MEMS technology, which enables the fabrication of miniaturized mechanical and electro-mechanical devices, such as acoustic transducers, used in a wide range of products including consumer electronics, automotive systems, and robotics.
• Key Procedural History: The complaint states that Plaintiff previously sued TDK Corporation and TDK Corporation of America in the Eastern District of Texas on November 8, 2022, for infringement of the same patents. That case was dismissed without prejudice on May 1, 2023, following an agreement to pursue an out-of-court resolution, which was ultimately unsuccessful. This history is cited to establish Defendants' knowledge of the patents-in-suit.

Case Timeline

Date	Event
2007-12-07	U.S. Patent No. 7,812,505 Priority Date
2007-12-18	U.S. Patent No. 8,114,697 Priority Date
2010-10-12	U.S. Patent No. 7,812,505 Issued
2012-02-14	U.S. Patent No. 8,114,697 Issued
2022-11-08	Prior lawsuit filed against TDK in E.D. Texas
2023-05-01	Prior lawsuit dismissed without prejudice
2025-10-06	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,812,505, Piezoelectric Microspeaker Using Microelectromechanical Systems and Method of Manufacturing the Same, issued October 12, 2010 ('505 Patent)

The Invention Explained

• Problem Addressed: The patent's background describes an issue in miniaturized MEMS speakers where resonance frequencies can fall within the audible range, creating undesirable noise and degrading sound quality ʼ505 Patent, col. 1:41-44 While complex structures can mitigate this, they increase manufacturing costs ʼ505 Patent, col. 1:48-53
• The Patented Solution: The invention proposes a "resonance change unit," which is a patterned structure on either the elastic thin layer or the piezoelectric layer ʼ505 Patent, abstract This unit, described as a "protrusion structure," intentionally alters the mass and stiffness of the speaker's diaphragm to shift the resonance frequency out of the audible band, thereby improving sound quality through a potentially simpler manufacturing process ʼ505 Patent, col. 6:21-29 ʼ505 Patent, col. 6:63-66
• Technical Importance: The invention offered a method to manage acoustic resonance in MEMS speakers through structural patterning, aiming to improve sound quality while avoiding the higher costs associated with more complex diaphragm designs ʼ505 Patent, col. 2:47-54

Key Claims at a Glance

• The complaint asserts independent claim 1 Compl. ¶27
• Claim 1 requires:
  • A piezoelectric layer disposed on an elastic thin layer; and
  • A resonance change unit patterned on one of a bottom surface of the elastic thin layer and a top surface of the piezoelectric layer.
• The complaint reserves the right to assert additional claims Compl. ¶27

U.S. Patent No. 8,114,697, Piezoelectric Microphone, Speaker, Microphone-Speaker Integrated Device and Manufacturing Method Thereof, issued February 14, 2012 ('697 Patent)

The Invention Explained

• Problem Addressed: The patent background notes that piezoelectric microphones can suffer from low sensitivity due to residual strain, while microspeakers can have low output ʼ697 Patent, col. 1:41-45
• The Patented Solution: For a speaker, the invention discloses a piezoelectric plate that is "differentially etched" to have two distinct regions: a thicker central "piezoelectric strain region" where the electrode is placed, and a thinner outer "vibration region" ʼ697 Patent, col. 2:12-18 This differential thickness is designed to optimize the mechanical vibration of the plate and improve sound output ʼ697 Patent, col. 7:10-14
• Technical Importance: This design provides a way to engineer the mechanical properties of a MEMS speaker diaphragm by creating regions with different thicknesses, allowing for improved acoustic performance and output from a miniaturized device ʼ697 Patent, abstract

Key Claims at a Glance

• The complaint asserts independent claim 10 Compl. ¶47
• Claim 10 requires a piezoelectric speaker comprising:
  • A silicon substrate;
  • An insulating layer provided over the silicon substrate;
  • A piezoelectric plate provided over the insulating layer, including a piezoelectric strain region and a vibration region;
  • A mating electrode provided in the piezoelectric strain region;
  • Wherein the piezoelectric plate is thinner in the vibration region than in the piezoelectric strain region.
• The complaint reserves the right to assert additional claims Compl. ¶47

III. The Accused Instrumentality

Product Identification

The accused products include the Chirp CH101 and CH201 Ultrasonic Time-of-Flight (ToF) Sensors, the ICU-series of ultrasonic sensors, the USSM1.0 PLUS-FS sensor module, and other TDK ultrasonic sensors and microspeakers Compl. ¶28 Compl. ¶48

Functionality and Market Context

The complaint identifies the accused products as ultrasonic sensors used for a variety of applications, including "range-finding, presence and proximity sensing, object-detection and avoidance, and position-tracking" Compl. ¶18 They are allegedly incorporated into products for robotics, home automation, AR/VR, and drones, among others, enabling "flexible industrial design options for a broad range of use-case scenarios" Compl. ¶18 Compl. ¶38

IV. Analysis of Infringement Allegations

'505 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a piezoelectric layer disposed on an elastic thin layer	The TDK Ultrasonic Sensors, such as the CH101, allegedly include a piezoelectric layer (107) disposed on an elastic thin layer, identified as a polysilicon membrane.	¶31	col. 5:61-64
a resonance change unit patterned on one of a bottom surface of the elastic thin layer and a top surface of the piezoelectric layer	The sensors allegedly include a "setback" (103a), identified as the claimed resonance change unit, which is patterned on the bottom surface of the polysilicon membrane (elastic thin layer).	¶32	col. 6:5-9

The complaint includes a magnified cross-section image from a teardown report, labeling the alleged piezoelectric layer within the accused CH101 sensor Compl. Fig. 2 Another annotated image purports to show the "setback" feature on the bottom of the elastic layer, which the complaint equates to the claimed "resonance change unit" Compl. Fig. 3

Identified Points of Contention

• Scope Questions: A potential dispute may arise over whether the accused "setback" feature constitutes a "resonance change unit" as claimed. A court may need to determine if the term, as understood in light of the patent's specification, requires a specific structure or functional outcome (e.g., shifting resonance out of the audible band) that the accused feature may or may not possess.
• Technical Questions: The '505 patent focuses on solving a problem of noise in the audible frequency band. The accused products are designed as ultrasonic sensors. This raises the question of whether the '505 patent's teachings are applicable to devices designed to operate in the ultrasonic range, and whether the accused "setback" performs the same function as the patented "resonance change unit" in this different technical context.

'697 Patent Infringement Allegations

Claim Element (from Independent Claim 10)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a silicon substrate	The CH101 sensor allegedly includes a silicon substrate.	¶51	col. 4:41-43
an insulating layer provided over the silicon substrate	The CH101 sensor allegedly has an insulating layer, which is identified as a polysilicon membrane (603), an air gap in the setback (603a), and/or a thin aluminum nitride layer.	¶52	col. 4:50-53
a piezoelectric plate provided over the insulating layer, the piezoelectric plate including a piezoelectric strain region and a vibration region	The CH101 allegedly has a piezoelectric AlN plate (605) over the insulating layer, which includes a piezoelectric strain region and a vibration region with different thicknesses.	¶53	col. 2:12-14
a mating electrode provided in the piezoelectric strain region of the piezoelectric plate	The CH101 allegedly includes a top electrode provided in the thicker piezoelectric strain region of the plate.	¶53	col. 2:14-15
wherein the piezoelectric plate is thinner in the vibration region than in the piezoelectric strain region	The piezoelectric plate (605) in the CH101 is allegedly thinner in its vibration region than in its piezoelectric strain region.	¶53	col. 2:15-18

The complaint provides an annotated cross-section of the CH101 sensor, highlighting a "polysilicon membrane 603" as the alleged insulating layer Compl. Fig. 5 A further magnified image purports to show the piezoelectric plate (605) with differential thickness, situated above the insulating layer (603) Compl. Fig. 6

Identified Points of Contention

• Scope Questions: The complaint pleads three alternative structures for the "insulating layer" limitation (a polysilicon membrane, an air gap, or an aluminum nitride layer) Compl. ¶52 This suggests a potential dispute over whether any of these features, particularly an "air gap," can be construed to meet the structural requirement of an "insulating layer provided over the silicon substrate."
• Technical Questions: The infringement allegation depends on the accused device having a piezoelectric plate with a specific differential thickness profile. The evidentiary basis for this assertion, derived from the SEM images in the complaint, may become a key point of technical dispute regarding whether the accused product's physical structure actually maps onto the claim's requirements.

V. Key Claim Terms for Construction

'505 Patent Term: "resonance change unit"

• Context and Importance: This term defines the core inventive feature of the '505 patent. The infringement analysis will turn on whether the accused "setback" falls within the scope of this term.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claim language itself does not specify a particular structure, only a "unit" that is "patterned." The specification describes its function as varying stiffness and mass to change the resonance frequency, which may support a functional definition ʼ505 Patent, col. 6:63-66
  • Evidence for a Narrower Interpretation: An embodiment is described as a "protrusion structure" left after a specific etching process ʼ505 Patent, col. 6:21-24 A defendant may argue that the term should be limited to this specific structural configuration or its method of formation.

'697 Patent Term: "insulating layer"

• Context and Importance: The plaintiff's case for the '697 patent depends on one of its proposed candidates (polysilicon membrane, air gap, AlN layer) meeting this limitation. The construction of this term is therefore critical.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The term itself is general. Plaintiff may argue that any structure providing the necessary electrical insulation between the piezoelectric plate and the substrate fulfills the claim's requirement.
  • Evidence for a Narrower Interpretation: The patent figures depict the insulating layer as a solid thin film upon which other layers are fabricated ʼ697 Patent, Fig. 8, element 803 A defendant could argue that an "air gap" does not constitute a structural "layer provided over the...substrate" in the manner disclosed and is instead merely empty space.

VI. Other Allegations

Indirect Infringement

The complaint alleges both induced and contributory infringement for both patents (Compl. ¶¶33; Compl. ¶40; Compl. ¶54; Compl. ¶61). For inducement, it alleges Defendants had knowledge of the patents, at least from a prior lawsuit, and encouraged infringement by providing customers with specifications, promotional literature, and technical support for integrating the accused sensors into end products (Compl. ¶34; Compl. ¶35; Compl. ¶36; Compl. ¶37; Compl. ¶38).

Willful Infringement

The complaint alleges willful infringement based on Defendants' continued infringement despite having knowledge of the patents and their alleged infringement, with knowledge dating back at least to notice provided around November 7, 2022, for TDK entities and prior to May 1, 2023, for InvenSense Compl. ¶¶41-42 Compl. ¶¶62-63

VII. Analyst's Conclusion: Key Questions for the Case

The resolution of this case may depend on the court's determination of several key technical and legal questions:

• A question of definitional scope: Can the '505 patent's "resonance change unit," a term rooted in solving an audible-range noise problem, be construed to read on the "setback" feature of an ultrasonic sensor, or is there a fundamental mismatch in technical context and function?
• A question of claim construction: For the '697 patent, the case may turn on whether an "air gap" or other internal component of the accused sensor can be properly construed as the claimed "insulating layer provided over the silicon substrate," an issue highlighted by the plaintiff's pleading of multiple alternatives for this single element.
• An evidentiary question of structural mapping: Does the physical structure of the accused sensors, as will be revealed through discovery and expert analysis, truly exhibit the specific differential-thickness profile required by claim 10 of the '697 patent, or is the plaintiff's interpretation based on the complaint's images a point of significant technical dispute?