DCT
2:22-cv-00434
MEMS Innovations LLC v. TDK Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: MEMS Innovations, LLC (Texas)
- Defendant: TDK Corporation (Japan); TDK Corporation of America (California)
- Plaintiff’s Counsel: Alavi & Anaipakos PLLC
- Case Identification: 2:22-cv-00434, E.D. Tex., 11/08/2022
- Venue Allegations: Venue is alleged to be proper for TDK Corporation as an alien corporation subject to personal jurisdiction in the district, and for TDK Corporation of America based on its maintenance of a regular and established place of business within the district.
- Core Dispute: Plaintiff alleges that Defendant’s ultrasonic Time-of-Flight (ToF) sensors, which utilize Microelectromechanical Systems (MEMS), infringe two patents related to the structure and manufacturing of piezoelectric microspeakers.
- Technical Context: The technology involves miniaturized acoustic transducers (speakers and microphones) built using semiconductor fabrication techniques, which are critical components in modern electronics for applications like proximity sensing, robotics, and Internet of Things (IoT) devices.
- Key Procedural History: The patents-in-suit were originally assigned to the Electronics and Telecommunications Research Institute (ETRI) in Korea. Plaintiff MEMS Innovations asserts it is the exclusive licensee with the right to enforce the patents. The complaint alleges that Defendants are not licensed to practice the patents.
I.A. Case Timeline
| Date | Event |
|---|---|
| 2007-12-07 | ’505 Patent Priority Date |
| 2007-12-18 | ’697 Patent Priority Date |
| 2010-10-12 | ’505 Patent Issue Date |
| 2012-02-14 | ’697 Patent Issue Date |
| 2022-11-08 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
II.A. 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 section notes that conventional MEMS transducers can suffer from poor performance, such as low output for speakers, due to residual tensile stress in the device's diaphragm. It also identifies a problem where a plurality of resonance frequencies fall within the audible frequency band, creating undesirable noise. (’505 Patent, col. 1:36-43).
- The Patented Solution: The invention describes a piezoelectric microspeaker that incorporates a "resonance change unit," which is a patterned structure on the diaphragm assembly. (’505 Patent, Abstract). This unit, described in the specification as a "protrusion structure," is designed to vary the stiffness and mass of the diaphragm to shift its resonance frequency from the audible band to an inaudible one, thereby improving sound quality and uniformity. (’505 Patent, col. 2:9-16; col. 6:21-30).
- Technical Importance: This design aimed to improve the acoustic performance of miniaturized speakers by mitigating unwanted noise from resonance, a key challenge in shrinking acoustic components, while using manufacturing techniques intended to lower production costs. (’505 Patent, col. 1:47-50).
Key Claims at a Glance
- The complaint asserts independent claim 1. (Compl. ¶23).
- The essential elements of claim 1 are:
- A piezoelectric microspeaker using microelectromechanical systems (MEMS), comprising:
- 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.
II.B. 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 identifies that piezoelectric acoustic transducers often have performance limitations, such as low sensitivity in microphones and low output in speakers, which can be attributed to tensile residual strain in the device’s vibration plate. (’697 Patent, col. 1:37-43).
- The Patented Solution: For a piezoelectric speaker, the patent proposes a "differentially etched" structure where the piezoelectric plate has two distinct regions: a thicker central "piezoelectric strain region" where the driving electrode is located, and a thinner "vibration region" at the outer circumference. (’697 Patent, Abstract; col. 2:8-17). The thinner outer region is more flexible and vibrates more readily in response to the strain generated in the central region, which is intended to improve the overall acoustic output of the speaker. (’697 Patent, col. 6:30-36).
- Technical Importance: This differential thickness design sought to enhance speaker output by engineering a more flexible vibrating structure without reducing the size of the active piezoelectric area, addressing a fundamental trade-off in MEMS transducer design. (’697 Patent, col. 6:37-43).
Key Claims at a Glance
- The complaint asserts infringement of what it identifies as "claim 1." (Compl. ¶42, ¶43). However, the language quoted in the complaint corresponds to claim 10 of the ’697 Patent. Claim 1 of the patent is a method claim for manufacturing a microphone.
- The essential elements of claim 10 (quoted in Compl. ¶43) are:
- A piezoelectric speaker comprising: a silicon substrate;
- an insulating layer provided over the silicon substrate;
- a piezoelectric plate provided over the insulating layer, the piezoelectric plate including a piezoelectric strain region and a vibration region; and
- a mating electrode provided in the piezoelectric strain region of the piezoelectric plate,
- wherein the piezoelectric plate is thinner in the vibration region than in the piezoelectric strain region.
III. The Accused Instrumentality
III.A. Product Identification
The accused products are the Chirp CH101, CH201, ICU-10201, and ICU-20201 Ultrasonic Time-of-Flight (ToF) Sensors, and any other TDK ultrasonic sensors with a similar structure (collectively, the "Chirp Sensors"). (Compl. ¶24, ¶41).
III.B. Functionality and Market Context
- The complaint alleges the Chirp Sensors are ultrasonic sensors that perform functions including range-finding, presence and proximity sensing, and object detection and avoidance. (Compl. ¶15).
- These sensors are allegedly incorporated into a wide array of end-products, including those for home automation, robotics, drones, augmented/virtual reality, gaming, and other IoT applications. (Compl. ¶15). The complaint asserts the sensors handle "a variety of ultrasonic signal-processing functions and algorithms" to enable "flexible industrial design options" for customers. (Compl. ¶35).
IV. Analysis of Infringement Allegations
IV.A. ’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 Chirp Sensors are alleged to include a piezoelectric layer disposed on a polysilicon membrane, which functions as an elastic thin layer. An exemplary cross-section of the accused CH101 sensor shows this structure. (Compl. Figure 2). | ¶27 | col. 5:61-62 |
| 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 Chirp Sensors are alleged to include a "setback" patterned on the bottom surface of the polysilicon membrane. This setback's dimensions allegedly define the resonance frequency of the device. An annotated cross-section of the accused CH101 sensor depicts this "setback" feature. (Compl. Figure 3). | ¶28 | col. 6:50-54 |
Identified Points of Contention:
- Scope Questions: A potential dispute may arise over the term "resonance change unit." The patent’s specification describes this element as a "protrusion structure." (’505 Patent, col. 6:50-51). The complaint alleges that the "setback" feature of the accused devices, which appears in complaint figures to be a recess or etched step, meets this limitation. (Compl. ¶28). The case may raise the question of whether the claimed "unit" can be read to cover a recess in addition to a protrusion.
- Technical Questions: The infringement claim rests on the allegation that the accused "setback" performs the function of defining the resonance frequency. (Compl. ¶28). A technical question for the court will be what evidence demonstrates that this specific structural element actually performs the claimed function of changing the resonance frequency as described in the patent. (’505 Patent, col. 2:9-16).
IV.B. ’697 Patent Infringement Allegations
| Claim Element (from Independent Claim 10) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a piezoelectric speaker comprising: a silicon substrate | The accused CH101 sensor is alleged to include a silicon substrate. (Compl. ¶44). | ¶44 | col. 11:9-10 |
| an insulating layer provided over the silicon substrate | The accused CH101 sensor allegedly has a polysilicon membrane provided over the silicon substrate, which serves as an insulating layer. An annotated image in the complaint highlights this layer. (Compl. Figure 5). | ¶44 | col. 11:9-11 |
| a piezoelectric plate provided over the insulating layer, the piezoelectric plate including a piezoelectric strain region and a vibration region | The accused CH101 sensor allegedly includes a piezoelectric plate disposed over the insulating layer, with regions of different thicknesses that are asserted to be the claimed strain and vibration regions. (Compl. ¶45). | ¶45 | col. 11:12-14 |
| a mating electrode provided in the piezoelectric strain region of the piezoelectric plate | The CH101 sensor is alleged to have a mating electrode provided in the thicker region of the piezoelectric plate, which is identified as the piezoelectric strain region. (Compl. ¶45). | ¶45 | col. 11:15-16 |
| wherein the piezoelectric plate is thinner in the vibration region than in the piezoelectric strain region | The complaint alleges that the piezoelectric plate in the accused CH101 sensor is thinner in its outer portion (the alleged vibration region) than in its central portion (the alleged strain region), as depicted in a provided cross-sectional image. (Compl. Figure 6). | ¶45 | col. 11:17-19 |
Identified Points of Contention:
- Legal Questions: The complaint contains a notable clerical error, repeatedly referencing "claim 1" of the ’697 Patent while quoting the text of claim 10. (Compl. ¶42, ¶43). While such errors are often correctable via amendment, this discrepancy creates an initial ambiguity regarding the precise claim being asserted.
- Technical Questions: The infringement theory depends on mapping the physical structure of the accused device onto the functional claim terms "piezoelectric strain region" and "vibration region." The central technical question will be whether the thicker and thinner portions of the accused device’s piezoelectric plate function in the manner described by the patent for these distinct regions.
V. Key Claim Terms for Construction
V.A. ’505 Patent: "resonance change unit"
- Context and Importance: This term represents the core inventive concept of the ’505 Patent. The infringement analysis for claim 1 hinges on whether the accused "setback" structure falls within the term's proper scope.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language itself does not specify a particular shape, stating only that the unit is "patterned on one of a bottom surface of the elastic thin layer and a top surface of the piezoelectric layer." (’505 Patent, col. 8:1-3).
- Evidence for a Narrower Interpretation: The detailed description repeatedly refers to the unit as a "protrusion structure" formed by "leaving the silicon during the etching of the silicon substrate." (’505 Patent, col. 6:50-57). Figure 1 of the patent also depicts a clear protrusion. This evidence may be used to argue the term is limited to additive or protrusive structures, not recesses.
V.B. ’697 Patent: "vibration region" and "piezoelectric strain region"
- Context and Importance: These terms define the differentially-etched structure that is central to claim 10. Practitioners may focus on these terms because infringement depends on successfully mapping the physical areas of the accused device to these functional descriptions.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language does not impose specific geometric or dimensional constraints beyond requiring the "vibration region" to be "thinner" than the "piezoelectric strain region" and for the mating electrode to be in the strain region. (’697 Patent, col. 15:20-24).
- Evidence for a Narrower Interpretation: The specification describes a functional relationship where the thinner "outer circumferential portion 603 vibrates depending on the strain generated" in the central pattern portion. (’697 Patent, col. 6:30-34). A defendant might argue these terms require a structure where the strain region actively drives vibration in a more passive, flexible vibration region, rather than simply denoting two areas of different thickness.
VI. Other Allegations
- Indirect Infringement: The complaint alleges that Defendants induce infringement by selling the accused Chirp Sensors to customers who incorporate them into infringing end-products. (Compl. ¶29, ¶45). The alleged acts of inducement include publishing specifications, promotional literature, and user manuals that encourage and provide instructions for such incorporation. (Compl. ¶34, ¶50).
- Willful Infringement: The complaint pleads willfulness based on alleged actual knowledge. It alleges Defendants had knowledge of the patents and infringement "at least as of November 7, 2022," one day prior to the complaint's filing, and also "as of the date of this Complaint." (Compl. ¶30-32, ¶46-48). This suggests the complaint itself may be the primary basis for post-suit knowledge. The complaint also alleges willful blindness. (Compl. ¶33, ¶49).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of structural interpretation: Can the term "resonance change unit" in the ’505 Patent, which the specification describes as a "protrusion structure," be construed to cover the accused device's "setback," which appears to be an etched recess?
- A key evidentiary question will be one of functional mapping: Does the accused sensor's piezoelectric plate, with its varying thicknesses, contain functionally distinct "piezoelectric strain" and "vibration" regions as required by the ’697 Patent, or is this a superficial characterization of a structure that operates in a fundamentally different manner?
- A threshold procedural issue is the impact of a clerical error: How will the parties and the court resolve the complaint’s assertion of "claim 1" of the ’697 Patent when the infringement allegations are based on the language of claim 10?