DCT
6:21-cv-01176
D4D Tech LLC v. Medit Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: D4D Technologies, LLC (Delaware)
- Defendant: Medit Corporation (Republic of Korea)
- Plaintiff’s Counsel: Scheef & Stone, LLP
- Case Identification: 6:21-cv-01176, W.D. Tex., 11/12/2021
- Venue Allegations: Plaintiff alleges venue is proper because Defendant is a foreign corporation not resident in the U.S., which makes venue appropriate in any judicial district.
- Core Dispute: Plaintiff alleges that Defendant’s Medit i500 and i700 intraoral scanner systems infringe patents related to high-speed 3D digital imaging and photogrammetry.
- Technical Context: The technology at issue involves structured light projection and digital image processing to create precise three-dimensional models of objects, primarily for dental computer-aided design and manufacturing (CAD/CAM).
- Key Procedural History: Plaintiff alleges it sent a notice letter to Defendant in October 2020, identifying the patents-in-suit and the accused i500 scanner, and offered to discuss licensing. After receiving no response, Plaintiff sent similar letters to Defendant's distributors in December 2020, which also did not result in a license.
Case Timeline
| Date | Event |
|---|---|
| 2003-09-17 | ’668 Patent Priority Date |
| 2006-10-25 | ’892 Patent Priority Date |
| 2008-03-11 | ’668 Patent Issue Date |
| 2011-07-12 | ’892 Patent Issue Date |
| 2018 | Accused Medit i500 Scanner launched |
| 2020-10 | Plaintiff sent notice letter to Defendant Medit |
| 2020-12 | Plaintiff sent notice letters to Medit distributors |
| 2021 | Accused Medit i700 Scanner launched |
| 2021-11-12 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,342,668 - “High Speed Multiple Line Three-Dimensional Digitalization” (issued Mar. 11, 2008)
The Invention Explained
- Problem Addressed: The patent addresses the shortcomings of prior art 3D imaging techniques from the early 2000s, such as Moiré systems, which were described as having low depth resolution, requiring substantial processing time or multiple images, and sometimes needing a powder coating on the object that could introduce errors (Compl. ¶¶9-10; ’668 Patent, col. 1:42-53).
- The Patented Solution: The invention proposes a method and system for high-speed 3D digitization by projecting a sequence of light patterns onto an object. Each pattern consists of multiple "distinguishable curvilinear lines." By capturing the reflection of these structured patterns, the system can rapidly calculate the x, y, z coordinates of the object's surface, enabling the acquisition of a full frame of 3D data much faster than previous methods (’668 Patent, Abstract; col. 2:55-65).
- Technical Importance: The described approach aimed to significantly reduce the time needed to acquire a 3D image, making the technology more suitable for time-sensitive applications like chairside dental scanning and restoration design (’668 Patent, col. 2:1-11).
Key Claims at a Glance
- The complaint asserts independent claims 1 (method), 19 (means-plus-function system), and 20 (system) (Compl. ¶23).
- Independent Claim 1 (method) requires:
- projecting a plurality of sequential light patterns onto a surface, where each pattern includes a plurality of distinguishable curvilinear lines
- capturing light reflected from the surface
- determining x, y, z coordinates of points on the surface based on the captured light
- using the coordinates to generate a representation of the object
- Independent Claim 19 (system) requires means for performing functionally similar steps to claim 1.
- Independent Claim 20 (system) requires a projector, a camera, a controller, and a display to perform functionally similar steps to claim 1.
U.S. Patent No. 7,978,892 - “3D Photogrammetry Using Projected Patterns” (issued Jul. 12, 2011)
The Invention Explained
- Problem Addressed: The patent identifies a key challenge in traditional photogrammetry: accurately matching corresponding pixels between two images is computationally expensive and difficult when the object's surface, such as a tooth, lacks distinct features (’892 Patent, col. 1:21-27).
- The Patented Solution: The invention combines structured light scanning with photogrammetry. First, a structured light pattern is projected onto the object to generate an initial 3D model. This initial model is then used as a guide to greatly simplify the process of finding "matched pixels" between images taken from different positions. Once pixels are matched, photogrammetry techniques are used to calculate a more accurate final 3D model (’892 Patent, Abstract; col. 2:31-43).
- Technical Importance: This hybrid method was designed to achieve the high accuracy of photogrammetry while mitigating its primary weakness on feature-poor surfaces, thereby making it more robust for applications like dental imaging (’892 Patent, col. 2:38-43).
Key Claims at a Glance
- The complaint asserts independent claims 1 and 6, both of which are method claims (Compl. ¶33).
- Independent Claim 1 (method) requires:
- projecting a pattern onto an object from at least a first and second position
- capturing an image (P) of the pattern and a separate illumination image (I) from each position
- forming a 3D model by analyzing distortions in the pattern image P
- using that 3D model to find a "matched pixel" between the illumination images (I) from the two positions
- using photogrammetry to determine 3D coordinates for each matched pixel
- Independent Claim 6 (method) is structurally similar to claim 1, reciting the capture of at least two pattern images (P1, P2) and two illumination images (I1, I2).
III. The Accused Instrumentality
- Product Identification: The accused instrumentalities are the Medit i500 Intraoral Scanner, the Medit i700 Intraoral Scanner, and the accompanying iScan and Medit Link software, collectively referred to as the "iSeries" (Compl. ¶¶1, 4).
- Functionality and Market Context: The complaint alleges the iSeries are scanner systems used by dental professionals to create 3D digital models of a patient's mouth for use in CAD/CAM workflows, such as designing and manufacturing crowns, bridges, and orthodontic aligners (Compl. ¶8). Plaintiff D4D also manufactures and sells competing scanner systems and alleges damages from lost sales due to the infringing iSeries products (Compl. ¶¶15, 31, 39). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
’668 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| projecting a plurality of sequential light patterns onto a surface of an object, where each of the plurality of sequential patterns includes a plurality of distinguishable curvilinear lines | The complaint alleges that use of the iSeries involves projecting sequential light patterns with distinguishable curvilinear lines onto a surface. | ¶24 | col. 5:32-42 |
| capturing light reflected from the surface | The iSeries allegedly captures light reflected from the surface being scanned. | ¶24 | col. 5:43-44 |
| determining coordinates x, y, z of points on the surface according to the captured light | The iSeries allegedly determines the 3D coordinates of surface points based on the captured light. | ¶24 | col.5:46-48 |
| using the coordinates to generate a representation of the physical object | The iSeries allegedly uses the determined coordinates to generate a 3D representation of the object. | ¶24 | col. 5:49-51 |
’892 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| projecting a pattern onto the object from at least first and second positions | The iSeries is allegedly used to project a pattern onto an object from multiple positions as the operator moves the scanner. | ¶34 | col. 3:1-17 |
| forming a 3D model of the object for each of the first and second positions by analyzing observed distortions to the pattern P caused by a 3D surface of the object | The complaint alleges the iSeries forms a 3D model by analyzing how the object's surface distorts the projected pattern. | ¶34 | col. 3:3-10 |
| using the 3D model in conjunction with each illumination image I to find a pixel in the illumination image I of the object from the first position that corresponds to a pixel in the illumination image I of the object from the second position, wherein the corresponding pixels are a matched pixel | The iSeries allegedly uses the 3D model created from the pattern distortion to find corresponding, or "matched," pixels between images. | ¶34 | col. 4:31-49 |
| using photogrammetry to determine 3D coordinates for each matched pixel | The iSeries allegedly uses photogrammetry to calculate the final 3D coordinates for the matched pixels. | ¶34 | col. 5:1-6 |
- Identified Points of Contention:
- Scope Questions: For the ’668 Patent, a central dispute may concern the meaning of "distinguishable curvilinear lines." The patent describes creating "non-rectangular regions of distinguishability" to avoid overlap (’668 Patent, col. 5:12-25, FIG. 5). This raises the question of whether the patterns projected by the iSeries meet this specific technical requirement or if a broader interpretation of "distinguishable" applies.
- Technical Questions: For the ’892 Patent, the claim requires a specific two-step sequence: (1) create a 3D model from pattern distortion, then (2) use that model to aid a photogrammetry analysis. A key factual question will be whether the iSeries software actually performs this sequential process, or if it uses a different, more integrated algorithm for 3D reconstruction that does not separate the steps in the claimed manner.
V. Key Claim Terms for Construction
The Term: "distinguishable curvilinear lines" (’668 Patent, Claim 1)
- Context and Importance: This term defines the nature of the projected light pattern, which is a core component of the ’668 invention. The infringement analysis will depend heavily on whether the iSeries' projected pattern meets the definition of this term.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The plain language could be argued to encompass any set of curved lines that a camera system can differentiate without ambiguity.
- Evidence for a Narrower Interpretation: The specification provides a specific example of how distinguishability is achieved, stating that "non-rectangular regions of distinguishability may be defined as areas between adjacent projection lines" such that "substantially no overlap exists between adjacent areas" (’668 Patent, col. 5:12-25). A party could argue this disclosure limits the term to patterns with such defined, non-overlapping regions.
The Term: "using the 3D model... to find a... matched pixel" (’892 Patent, Claim 1)
- Context and Importance: This phrase describes the crucial link between the initial structured-light scan and the subsequent photogrammetry step. The case may turn on whether the accused algorithm follows this specific sequence of operations.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party might argue that any algorithm where 3D data generally informs the pixel-matching process satisfies this limitation.
- Evidence for a Narrower Interpretation: The specification describes a specific computational method where a 3D coordinate from a first data set is used to predict a pixel location in a second image, thereby restricting the search for a "matched pixel" to a small "neighborhood" around the predicted location (’892 Patent, col. 4:31-49). This suggests the "using" step is an explicit computational constraint, not just a general relationship.
VI. Other Allegations
- Indirect Infringement: The complaint alleges active inducement of infringement for the asserted method claims (1 and 6 of the ’892 patent; 1 of the ’668 patent). The basis for this allegation is that Medit sells the iSeries with the intent that its customers will use the devices in their normal, intended manner, which allegedly constitutes direct infringement. The complaint references user guides as evidence of these instructions (Compl. ¶¶24, 25, 34, 35, 36, 37).
- Willful Infringement: The complaint alleges that Medit’s infringement has been willful since at least October 2020. This is based on a notice letter D4D allegedly sent to Medit providing actual notice of the patents-in-suit and the infringing nature of the i500 product. Medit’s alleged continued sales after receiving this notice form the basis of the willfulness claim (Compl. ¶¶17, 30, 38).
VII. Analyst’s Conclusion: Key Questions for the Case
- A key evidentiary question will be one of algorithmic implementation: does the accused iSeries software perform the specific two-stage process claimed in the ’892 patent—first generating a 3D model via structured light analysis and then using that model to explicitly constrain a separate photogrammetric pixel-matching process—or does it employ a different, more unified 3D reconstruction algorithm?
- A core issue for the ’668 patent will be one of definitional scope: can the term "distinguishable curvilinear lines" be met by any projected pattern that is simply separable, or does the patent’s description of "non-rectangular regions" and the avoidance of overlap (’668 Patent, col. 5:12-25) impose a more stringent structural requirement that the accused pattern must meet?
- The allegation of willfulness will likely depend on the receipt and content of the October 2020 notice letter. The central question will be whether the notice was sufficiently specific to give Medit knowledge of its alleged infringement, thus triggering a duty to investigate and avoid ongoing infringement of the patent claims.