Densys Ltd v. Medit Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Densys Ltd. (Israel)
  • Defendant: Medit Corp. (South Korea)
  • Plaintiff’s Counsel: Farnan LLP; Susman Godfrey L.L.P.
• Case Identification: 1:25-cv-00769, D. Del., 06/20/2025
• Venue Allegations: Plaintiff alleges venue is proper because Defendant, a foreign corporation, has committed acts of infringement in Delaware, and alternatively, because as a foreign corporation not resident in the U.S., venue is proper in any judicial district.
• Core Dispute: Plaintiff alleges that Defendant’s intraoral scanner products and associated software infringe patents related to three-dimensional digital imaging and modeling of the oral cavity.
• Technical Context: The lawsuit concerns the technology of intraoral scanners, which digitally capture the three-dimensional topography of a patient's teeth and gums to replace traditional physical impression materials in dentistry.
• Key Procedural History: The complaint highlights a prior case, Densys v. 3Shape, where a jury in the Western District of Texas found that competitor 3Shape willfully infringed the ’707 Patent. Plaintiff leverages this verdict to support its willfulness allegations against Medit, alleging Medit's products are "similar in all material respects" to 3Shape's. The ’257 Patent underwent an ex parte reexamination, resulting in the confirmation of claim 1 and the addition of new dependent claims clarifying the nature of the claimed "random" patterns.

Case Timeline

Date	Event
2000-06-28	U.S. Patent No. 6,402,707 Priority Date (Filing Date)
2002-06-11	U.S. Patent No. 6,402,707 Issue Date
2006-01-11	U.S. Patent No. 8,665,257 Priority Date (PCT Filing Date)
2014-03-04	U.S. Patent No. 8,665,257 Issue Date
2019-01-01	Alleged Infringement Start Date (First year mentioned)
2019-08-20	U.S. Patent No. 8,665,257 Reexamination Certificate Issued
2025-06-20	Complaint Filing Date

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

U.S. Patent No. 6,402,707 - "Method and system for real time intra-orally acquiring and registering three-dimensional measurements and images of intra-oral objects and features," Issued June 11, 2002

The Invention Explained

• Problem Addressed: The patent describes the difficulty in creating a complete and accurate 3D map of a patient's mouth using a handheld scanner (’707 Patent, col. 4:1-5). When multiple scans from different positions are "stitched" together, any error in calculating the scanner's precise location and orientation for each scan propagates, reducing the accuracy of the final composite model (’707 Patent, col. 8:51-60). Prior art methods to solve this, such as electromechanical arms or placing visible markers in the scan area, were described as cumbersome and limiting (’707 Patent, col. 6:35-50).
• The Patented Solution: The invention proposes establishing a single "intra-oral fixed global registration position" inside the patient's mouth but not necessarily within the field of view of every scan (’707 Patent, col. 9:8-14, col. 24:49-54). A mobile scanning probe, containing its own mobile registration device, captures images of the teeth. The system records the probe's position relative to this single fixed point for each image captured (’707 Patent, col. 9:18-29). This allows all the individual 3D images to be accurately registered into a common coordinate system, creating a precise panoramic map without the propagation errors of sequential "stitching" (’707 Patent, Abstract).
• Technical Importance: This approach decouples the imaging process from the registration reference, potentially enabling a freely moving scanner to create a full-mouth scan more quickly and accurately by referencing a single, stable coordinate origin. (Compl. ¶18).

Key Claims at a Glance

• The complaint asserts independent claims 1 (method) and 37 (system) (’Compl. ¶29).
• Key elements of independent method claim 1 include:
  • (a) establishing an intra-oral fixed global registration position inside the oral cavity of a dental patient
  • (b) providing a measuring and imaging device
  • (c) selecting a field of view of the device at a global position
  • (d) acquiring a 3D measurement and image in that field of view, and recording the device's global position relative to the intra-oral fixed global registration position
  • (e) repeating steps (c) and (d) for a plurality of positions and fields of view
  • (f) registering local coordinate space pixel positions from the plurality of images with corresponding global coordinate space pixel positions
• The complaint reserves the right to assert additional claims.

U.S. Patent No. 8,665,257 - "Three-dimensional modeling of the oral cavity," Issued March 4, 2014

The Invention Explained

• Problem Addressed: The patent identifies a fundamental challenge in optical scanning: surfaces that lack distinct features, like teeth, provide insufficient detail for the system to reliably match corresponding points between different images, a necessary step for 3D reconstruction via triangulation (’257 Patent, col. 2:51-54).
• The Patented Solution: Instead of relying on the tooth's natural surface, the invention projects a pre-defined, stored pattern of "structured illumination" onto the intra-oral scene (’257 Patent, Abstract). The system captures an image of the scene with the projected pattern deformed by the surface's topography. It then calculates the 3D coordinates by triangulation, comparing the captured, deformed pattern to a stored reference image of the same pattern projected onto a known reference surface (e.g., a plane) (’257 Patent, col. 5:60-65; FIG. 4). The patterns are described as "random" and reproducible, which serves as an anti-aliasing mechanism to ensure each point in the pattern is unique and can be matched unambiguously (’257 Patent, col. 5:60-62, col. 8:24-30).
• Technical Importance: This method creates artificial surface features using light, enabling accurate 3D modeling of otherwise featureless surfaces without requiring physical powdering or complex multi-camera setups. (Compl. ¶18-19).

Key Claims at a Glance

• The complaint asserts independent claim 1 (system) (’Compl. ¶44).
• Key elements of independent system claim 1 include:
  • a pattern generator for generating an array of random two-dimensional or one-dimensional patterns
  • a projectable medium with a memory for storing the array
  • a projector for projecting the array onto the intra-oral scene
  • an acquiring unit (camera) for acquiring images of the projected array
  • a first position calculator
  • a pattern-matching software
  • a parallax calculator
  • a second position calculator
  • a modeling software for constructing a 3D model
• The complaint reserves the right to assert additional claims.

III. The Accused Instrumentality

Product Identification

• The "Accused Products" are identified as Medit's intraoral scanners sold in the U.S. from 2019 to present, including the i900, i900 Classic, i700, i700 Wireless, i600, and i500 models (the "Medit Scanners"). The term also includes associated software such as Medit Scan and Medit Link. (Compl. ¶21).

Functionality and Market Context

• The complaint alleges these components work together as a complete intraoral scanning system to generate virtual 3D models for dental applications. (Compl. ¶21). The complaint positions Medit as "a significant player in the dental imaging market" and alleges the Accused Products generate substantial revenue. (Compl. ¶22-23).

IV. Analysis of Infringement Allegations

The complaint references preliminary claim charts in Exhibits 3 and 4 for its detailed infringement allegations concerning the ’707 and ’257 patents, respectively (Compl. ¶29, ¶44). As these exhibits were not filed with the complaint and are not available for review, a limitation-by-limitation analysis is not possible. The complaint’s narrative allegations are conclusory, stating only that the Accused Products "meet each and every limitation" of the asserted claims (Compl. ¶29, ¶44). No probative visual evidence provided in complaint.

• Identified Points of Contention:
  • ’707 Patent: A central question will be whether the Accused Products, in their normal operation, "establish[] an intra-oral fixed global registration position" as required by claim 1. The infringement analysis may turn on whether the plaintiff can prove the Medit system uses a single, fixed reference point within the oral cavity to register all scans, as opposed to a different registration method such as frame-to-frame stitching or referencing external markers.
  • ’257 Patent: The infringement analysis will likely focus on the specific method of 3D reconstruction. Key technical questions will include: (1) Does the Medit system project "random" patterns as that term is construed? (2) Does the system perform triangulation by comparing the captured image to a stored reference image of the pattern on a known surface, as taught by the patent, or does it use another technique (e.g., stereovision between two cameras or movement of a single camera) to achieve 3D reconstruction?

V. Key Claim Terms for Construction

’707 Patent

• The Term: "intra-oral fixed global registration position"
• Context and Importance: This term is the central inventive concept of the ’707 patent. Its construction will likely determine the scope of the claims and be dispositive for infringement. Practitioners may focus on whether this "position" requires a physical, separately placed device or if it can be a virtual point established by software.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: Claim 1 itself defines the term functionally as a position that is "definable in terms of global coordinate space" and is used as a reference for recording the scanner's position (’707 Patent, col. 24:35-42). This language does not explicitly require a physical object.
  • Evidence for a Narrower Interpretation: The specification's primary embodiment describes an "intra-oral fixed global registration device 34" that is physically positioned and fixed inside the oral cavity to create the registration position (’707 Patent, col. 12:59-62; col. 13:23-27). An argument could be made that the claims should be limited to this disclosed embodiment.

’257 Patent

• The Term: "random two-dimensional or one-dimensional patterns"
• Context and Importance: The "random" nature of the projected patterns is critical for the patent's anti-aliasing function. The outcome of the case may depend on whether the patterns used by Medit's scanners fall within the construed definition of "random." The importance of this term is underscored by the new claims added during reexamination, which further specify that the patterns are "randomly shaped" and/or "randomly distributed."
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification contrasts the invention with prior art using regular grids or non-reproducible laser speckle, suggesting "random" could be interpreted broadly to mean any reproducible, non-regular, or aperiodic pattern sufficient to avoid ambiguity (’257 Patent, col. 3:36-38; col. 4:38-51).
  • Evidence for a Narrower Interpretation: The term could be construed more narrowly to require patterns that are generated by a particular probabilistic process or exhibit specific statistical properties of randomness. The specification notes that the patterns are "probabilistically unique over the entire area" (’257 Patent, col. 8:26-28), which may support a more stringent definition.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, stating that Medit provides promotional materials, user guides, and training that instruct and encourage customers and end-users (e.g., dentists) to operate the Accused Products in an infringing manner (Compl. ¶33-34, ¶48-49).
• Willful Infringement: The willfulness allegation is based on both pre- and post-suit knowledge. For pre-suit knowledge of the ’707 patent, the complaint specifically alleges that Medit, as a "significant player," was aware of the willful infringement verdict against its competitor 3Shape for similar products (Compl. ¶23). For both patents, it is alleged that the filing of the complaint provides notice, making any subsequent infringement willful (Compl. ¶24).

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

The resolution of this case will likely depend on the court’s determination of several central issues:

1. A core issue of claim construction will be the definition of "intra-oral fixed global registration position" in the ’707 Patent. The case may turn on whether this term is limited to the physical registration device shown in the embodiments or can be construed more broadly to cover a software-defined virtual reference point.
2. A key evidentiary question will be one of operational fact regarding the ’257 Patent: can Densys prove that the Medit scanners' 3D reconstruction process functions as claimed—specifically, by projecting reproducible "random" patterns and performing triangulation against a stored reference image—or do the accused systems employ a different, non-infringing optical method?
3. The allegation of willful infringement will present a significant legal and factual question. The court will need to assess whether the prior infringement verdict against a competitor, 3Shape, on the ’707 Patent is sufficient to establish that Medit acted with the requisite knowledge and intent for pre-suit willfulness regarding its own "similar" products.