DCT
5:25-cv-00176
Denso Corp v. Qorvo Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Denso Corp (Japan)
- Defendant: Qorvo, Inc. (Delaware)
- Plaintiff’s Counsel: Yarbrough Wilcox, PLLC; WIGGIN AND DANA LLP
- Case Identification: 5:25-cv-00176, E.D. Tex., 11/26/2025
- Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant Qorvo maintains a regular and established place of business in Richardson, Texas, employs personnel in the district, and has committed acts of infringement within the district.
- Core Dispute: Plaintiff alleges that Defendant’s radio-frequency (RF) front-end modules, which contain Bulk Acoustic Wave (BAW) filters, infringe a patent related to piezoelectric thin films made of scandium-doped aluminum nitride.
- Technical Context: The technology at issue involves advanced materials used to fabricate high-performance RF filters, which are critical components for enabling the increased bandwidth and miniaturization required by 5G mobile communication systems.
- Key Procedural History: The complaint alleges that the parties had been engaged in confidential patent licensing negotiations prior to the lawsuit. It further alleges that on October 27, 2025, Defendant Qorvo filed a declaratory judgment action against Plaintiff, an act which Plaintiff claims breached a confidentiality agreement. Plaintiff also alleges it provided Defendant with notice of the patent-in-suit on November 29, 2023, a fact central to its willfulness claim.
Case Timeline
| Date | Event |
|---|---|
| 2007-05-31 | U.S. Patent No. 7,758,979 Priority Date |
| 2010-07-20 | U.S. Patent No. 7,758,979 Issue Date |
| 2023-11-29 | Date Plaintiff allegedly put Defendant on notice of infringement |
| 2025-10-27 | Date Defendant allegedly filed a Declaratory Judgment Action |
| 2025-11-26 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,758,979 - "Piezoelectric Thin Film, Piezoelectric Material, and Fabrication Method of Piezoelectric Thin Film and Piezoelectric Material, and Piezoelectric Resonator, Actuator Element, and Physical Sensor Using Piezoelectric Film"
- Patent Identification: U.S. Patent No. 7,758,979, “Piezoelectric Thin Film, Piezoelectric Material, and Fabrication Method of Piezoelectric Thin Film and Piezoelectric Material, and Piezoelectric Resonator, Actuator Element, and Physical Sensor Using Piezoelectric Film,” issued July 20, 2010 (’979 Patent).
The Invention Explained
- Problem Addressed: The patent’s background section describes a key limitation of conventional radio-frequency filters used in mobile devices. While aluminum nitride (AlN) is a preferable material for these filters due to its favorable characteristics, it has a low piezoelectric constant, meaning it is relatively inefficient at converting electrical signals to mechanical vibrations. This inefficiency can lead to higher power consumption and limit device performance (’979 Patent, col. 2:21-56).
- The Patented Solution: The invention solves this problem by adding a specific amount of scandium (Sc) to the aluminum nitride film, creating ScAlN (’979 Patent, col. 3:5-9). This doping process is described as significantly improving the film's piezoelectric response, allowing for better performance while retaining the other desirable properties of AlN (’979 Patent, col. 3:49-51). Figure 1 of the patent graphically illustrates the relationship between the scandium content ratio and the improvement in piezoelectric constant, showing a peak response at a specific concentration (’979 Patent, FIG. 1).
- Technical Importance: The development of ScAlN provided a material that could enable smaller, more efficient, and higher-performance RF filters, a critical advancement for meeting the technical demands of next-generation wireless standards like 5G (Compl. ¶¶27, 49).
Key Claims at a Glance
- The complaint asserts infringement of at least independent Claim 6 (Compl. ¶59).
- The essential elements of Claim 6 are:
- A piezoelectric thin film comprising an aluminum nitride thin film containing scandium.
- A content ratio of the scandium being in a range of 10 atom % to 35 atom % OR 40 atom % to 50 atom %.
- The content ratio is determined based on an assumption that the total number of scandium and aluminum atoms in the film is 100 atom %.
- The complaint’s prayer for relief reserves the right to assert infringement of "one or more claims of the Patent-in-Suit" (Compl. Prayer for Relief ¶B).
III. The Accused Instrumentality
Product Identification
- The accused products are Qorvo’s front-end modules for wireless communications, including but not limited to the QM78105 and QM76305 modules (Compl. ¶¶33-34).
Functionality and Market Context
- The accused modules are components used in wireless devices, such as smartphones, to manage radio-frequency signals (Compl. ¶33). These modules contain BAW filters that allegedly utilize scandium-doped aluminum nitride (ScAlN) piezoelectric films to enhance performance, such as increasing piezoelectric coupling to allow for wider bandwidths required for 5G applications (Compl. ¶38). The complaint cites a Qorvo white paper that allegedly acknowledges the use of "Scandium-doped AlN piezo layers" as "key to overcoming" challenges in 5G filter manufacturing (Compl. ¶36).
- The complaint alleges these modules are incorporated into high-volume consumer electronics, including the Apple iPhone 15 Pro, Apple iPhone 15 Pro Max, and Samsung Galaxy S21 (Compl. ¶40).
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint.
Claim Chart Summary
’979 Patent Infringement Allegations
| Claim Element (from Independent Claim 6) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A piezoelectric thin film comprising an aluminum nitride thin [film] containing scandium... | Qorvo's BAW filters, which are included in its front-end modules, allegedly use piezoelectric thin films made of scandium-doped aluminum nitride (ScAlN). | ¶38 | col. 3:39-42 |
| ...a content ratio of the scandium being in a range of 10 atom % to 35 atom % or 40 atom % to 50 atom %... | Plaintiff alleges that its testing of an accused Qorvo module (QM76305) found five BAW filters with scandium content ratios of 19.33, 19.02, 19.55, 19.13, and 26.38 atom %. These values fall within the 10-35 atom % range claimed in the patent. | ¶41 | col. 4:53-57 |
| ...on an assumption that a total amount of a number of atoms of the scandium and a number of atoms of aluminum in the aluminum nitride thin film is 100 atom %. | Plaintiff's alleged testing results are explicitly based on the same assumption recited in the claim language. | ¶41 | col. 3:45-48 |
Identified Points of Contention
- Evidentiary Question: The core of the direct infringement dispute may be factual. The complaint’s allegations hinge on its own testing of the accused products (Compl. ¶41). A central question will be whether discovery and expert analysis confirm that the scandium content ratio in Qorvo’s products falls within the specific numerical ranges recited in Claim 6, and whether the methodologies used for this measurement are reliable.
- Scope Question: Claim 6 recites two distinct ranges for the scandium content (10-35% or 40-50%), creating a gap between 35% and 40%. While the complaint alleges concentrations within the lower range, a potential point of contention could arise if Defendant's products are shown to have a scandium concentration that falls within this unclaimed gap.
V. Key Claim Terms for Construction
- The Term: "content ratio of the scandium"
- Context and Importance: This term is the central quantitative limitation of the asserted claim. The infringement analysis depends entirely on whether the accused products' material composition meets the specific numerical ranges defined by this term. Practitioners may focus on this term because the methodology for measuring and calculating this ratio will be a critical factual battleground.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim itself provides a clear basis for calculation: "on an assumption that a total amount of a number of atoms of the scandium and a number of atoms of aluminum in the aluminum nitride thin film is 100 atom %" (’979 Patent, col. 22:30-33). A party could argue this plain language provides a complete and straightforward definition, precluding more complex interpretations.
- Evidence for a Narrower Interpretation: The specification discloses specific fabrication processes, such as sputtering at certain power densities, that result in films with particular scandium content ratios (’979 Patent, col. 12:50-13:14). While arguments to limit a claim term to specific embodiments are often disfavored, a party might reference these sections to inform how one of ordinary skill in the art would have understood and measured the "content ratio" at the time of the invention.
VI. Other Allegations
- Indirect Infringement: The complaint states that discovery "may show additional infringements by inducement," but does not plead specific facts to support an inducement claim at this stage (Compl. ¶59).
- Willful Infringement: Plaintiff alleges willful infringement based on Defendant’s alleged actual knowledge of the ’979 Patent since at least November 29, 2023, when Plaintiff asserts it put Defendant on notice (Compl. ¶60). The complaint alleges that Defendant continued to make, use, and sell the accused products after receiving this notice (Compl. ¶62).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of evidentiary proof: Can Plaintiff produce sufficient technical evidence, likely through expert testing and analysis, to prove that the "content ratio of the scandium" in Defendant’s accused BAW filters falls squarely within the numerical ranges recited in the asserted patent claim? The case may turn on a factual dispute over material composition and measurement methodology.
- A second key question will address culpability and damages: Given the allegations of pre-suit notice and prior licensing negotiations, the court will need to determine if Defendant’s continued alleged infringement after November 2023 constituted willful conduct. This finding would be critical for Plaintiff’s request for enhanced damages.