DCT

2:17-cv-07083

Carl Zeiss AG v. Nikon Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:17-cv-07083, C.D. Cal., 09/26/2017
  • Venue Allegations: Venue is based on allegations that Defendant Nikon Inc. conducts substantial business in the district, including the sale and service of accused products, and maintains a regular and established place of business, specifically a factory service and repair center, in Los Angeles.
  • Core Dispute: Plaintiffs allege that Defendants’ digital cameras, which incorporate Nikon-designed image sensors and software, infringe three U.S. patents related to face detection algorithms and CMOS image sensor architecture.
  • Technical Context: The dispute centers on core technologies in digital photography: software-based methods for automatically detecting human faces within an image and the underlying semiconductor architecture of CMOS sensors used to capture the image.
  • Key Procedural History: The complaint alleges Defendants had pre-suit knowledge of the patents-in-suit or their direct parent patents from prior litigation filed by Plaintiffs against Nikon on April 28, 2017, in both the U.S. District Court (Case No. 2:17-cv-03225) and the International Trade Commission (ITC Inv. No. 337-TA-1059).

Case Timeline

Date Event
1998-05-08 U.S. Patent No. 6,731,335 Priority Date
1999-01-11 U.S. Patent No. 6,463,163 Priority Date
2002-10-08 U.S. Patent No. 6,463,163 Issues
2004-05-04 U.S. Patent No. 6,731,335 Issues
2005-01-31 U.S. Patent No. 9,728,574 Priority Date
2017-04-28 Prior District Court and ITC cases filed against Nikon
2017-08-08 U.S. Patent No. 9,728,574 Issues
2017-09-26 Complaint Filing Date

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

U.S. Patent No. 6,463,163 - “System and Method for Face Detection Using Candidate Image Region Selection,” issued October 8, 2002

The Invention Explained

  • Problem Addressed: The patent’s background section notes that conventional face detection systems were computationally intensive, which limited their speed and accuracy, making content-based image searches challenging (’163 Patent, col. 1:11-28). The patent identifies a need for a system that improves face detection performance in terms of both speed and accuracy (’163 Patent, col. 1:13-17).
  • The Patented Solution: The invention discloses a two-stage "pre-filtering" process to accelerate face detection. An initial "candidate selector" rapidly screens an image to identify regions that have a high probability of containing a face, while discarding large portions of the image that do not. This selector first uses a linear matched filter to find patterns similar to a face template, and then a non-linear filter to check for contrast patterns characteristic of human eyes. Only these "candidate regions" are then passed to a more resource-intensive face detector for final verification, thereby reducing the total computational workload (’163 Patent, Abstract; col. 2:20-33).
  • Technical Importance: This pre-filtering approach addresses the computational bottleneck in face detection, a key step for enabling such features in consumer devices with limited processing power.

Key Claims at a Glance

  • The complaint asserts infringement of at least Claim 1 (Compl. ¶54).
  • Independent Claim 1 requires a method of pre-filtering an input image by:
    • Receiving the input image;
    • Correlating the input image with preselected reference data to derive a correlation image;
    • Selecting a candidate region by identifying potential candidate regions based on detecting a local maximum in the correlation image; and
    • Screening the potential candidate regions by analyzing a grayscale characteristic.
  • The complaint reserves the right to assert other claims, including dependent claims (Compl. ¶¶16, 45).

U.S. Patent No. 6,731,335 - “CMOS Image Sensor Having Common Outputting Transistors and Method for Driving The Same,” issued May 4, 2004

The Invention Explained

  • Problem Addressed: The patent describes prior art CMOS image sensors that required four transistors for every pixel to perform correlated double sampling (CDS), a technique essential for high-quality, low-noise images. This architecture increased the overall chip size and, consequently, the cost of the sensor (’335 Patent, col. 2:57-62).
  • The Patented Solution: The patent teaches a pixel architecture where multiple photodiodes (the light-sensitive elements) share common output circuitry. In the disclosed embodiment, two photodiodes, each with its own transfer transistor, are connected to a single, shared set of reset, drive, and select transistors (’335 Patent, Abstract; Fig. 4). This structure reduces the average number of transistors per photodiode, allowing for a smaller, more compact, and less expensive image sensor chip (’335 Patent, col. 2:63-68).
  • Technical Importance: This circuit design contributes to the miniaturization and cost reduction of high-performance CMOS image sensors, a critical factor for the widespread adoption of digital cameras.

Key Claims at a Glance

  • The complaint asserts infringement of at least Claim 1 (Compl. ¶76).
  • Independent Claim 1 requires a method for driving a "unit pixel" that comprises two photodiodes and shared transistors, involving a specific sequence of:
    • Depleting the photodiodes;
    • Generating photoelectric charges;
    • Outputting a reset voltage level from the shared sensing node;
    • Outputting a data voltage level from the first photodiode;
    • Outputting a second reset voltage level; and
    • Outputting a data voltage level from the second photodiode.
  • The complaint reserves the right to assert other claims (Compl. ¶¶16, 67).

U.S. Patent No. 9,728,574 - “CMOS image sensor with shared sensing node,” issued August 8, 2017

  • Technology Synopsis: This patent addresses the limited charge storage capacity of a pixel's sensing node. The invention proposes connecting the sensing node of a pixel in a currently scanned row to the sensing node of a pixel in a previously scanned, adjacent row. This sharing, controlled by a switching transistor, temporarily increases the effective capacitance of the active sensing node, allowing it to handle more photocharge without saturation and improving image quality (’574 Patent, Abstract; col. 3:5-15).
  • Asserted Claims: At least Claim 1 (Compl. ¶99).
  • Accused Features: The image sensors within certain Nikon digital cameras, including the D4, D4S, and Df models (Compl. ¶¶90, 99).

III. The Accused Instrumentality

Product Identification

Various Nikon digital cameras and related software, including but not limited to the Nikon Coolpix S9900, D3300, D4, D4S, and Df models (Compl. ¶¶18, 45, 67, 90). The complaint specifically targets the cameras' "Face Priority AF" or "Face Detection" software features, as well as their internal CMOS image sensors, which are alleged to be designed by Nikon (Compl. ¶¶11-12, 54, 76).

Functionality and Market Context

The accused features relate to core functions of modern digital cameras. The "Face Priority AF" feature is alleged to automatically detect human faces in a scene to set the camera's focus, a key feature for portrait photography (Compl. ¶54). The accused CMOS sensors are the fundamental hardware component responsible for converting light into the digital image data (Compl. ¶76). The complaint emphasizes that Nikon designs its own image sensors "in-house to ensure maximum image quality" (Compl. ¶11). The complaint includes a diagram of Nikon's corporate governance structure to support its theory that the various Nikon entities operate as a single enterprise (Compl. p. 6, Exhibit D-1). This diagram from Nikon's website shows a Board of Directors supervising various committees and officers who oversee "Each department / Group companies" (Compl. p. 6).

IV. Analysis of Infringement Allegations

The complaint references, but does not attach, claim chart exhibits for each patent-in-suit (Exhibits K, O, and Q) (Compl. ¶¶54, 76, 99). The analysis below is based on the narrative infringement allegations provided in the complaint body.

’163 Patent Infringement Allegations

The complaint alleges that the "Face Priority AF" feature in accused Nikon cameras directly infringes the method of Claim 1 (Compl. ¶¶46, 54). The theory is that this feature performs the claimed "method of pre-filtering an input image" to locate a face, which is the "target image pattern of interest" (Compl. ¶56). The complaint asserts that the use of this method is "not optional during operation," suggesting it is an integral part of the camera's function (Compl. ¶56).

Identified Points of Contention

  • Scope Questions: A primary issue may be whether the accused "Face Priority AF" function is properly characterized as "pre-filtering" as that term is used in the patent. The defense may argue that its face detection is a single, integrated process rather than the distinct two-step "pre-filtering" and final "verifying" architecture described in the patent.
  • Technical Questions: A key factual question will be whether the accused software technically performs the specific sequence of (1) "correlating" an image with a template to find a "local maximum," followed by (2) "screening" those potential regions by "analyzing a grayscale characteristic." The complaint does not provide technical details on how the accused feature operates, leaving open the possibility that it uses an alternative algorithm (e.g., a Haar-like feature cascade) that may not map onto these claimed steps.

’335 Patent Infringement Allegations

The complaint alleges that the method of operating the image sensors in accused cameras, such as the Nikon D4 and Df, infringes Claim 1 (Compl. ¶¶68, 76). The allegation is that these sensors embody the claimed structure of multiple photodiodes sharing common output transistors and are driven by the specific sequence of reset and readout steps recited in the method claim (Compl. ¶76).

Identified Points of Contention

  • Technical Questions: The infringement analysis will depend on the precise architecture and operation of Nikon's proprietary CMOS sensors. It raises the questions of whether the sensors actually use a two-photodiode-per-shared-output structure and, if so, whether the camera's firmware drives those sensors using the exact sequence of activating and deactivating the reset and transfer transistors as recited in steps (c) through (f) of Claim 1.
  • Scope Questions: Claim 1 is directed to a method of driving a specific "unit pixel" structure defined as comprising two photodiodes. The construction of "unit pixel" will be critical. If Nikon's sensors are structured differently (e.g., one photodiode per pixel, with sharing occurring between pixels), it may raise a significant non-infringement question.

V. Key Claim Terms for Construction

’163 Patent: "pre-filtering an input image"

  • The Term: "pre-filtering an input image"
  • Context and Importance: This phrase in Claim 1 defines the nature of the claimed method. Its construction will determine whether a general-purpose face detection algorithm can be considered a "pre-filtering" step as contemplated by the patent.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification states the purpose of the pre-filtering operation is to "screen[] out much of the input image as regions that do not contain a human face," thereby reducing the computational load for a subsequent detector (’163 Patent, col. 2:25-33). This purpose-driven language could support a construction that covers any initial processing stage that reduces the search space.
    • Evidence for a Narrower Interpretation: The Summary of the Invention describes the "candidate selector" (which performs the pre-filtering) as operating "in series with an associated face detector that verifies whether the candidate regions do contain a human face" (’163 Patent, col. 2:22-25). This language suggests a distinct, modular system with a separate pre-filter and a separate verifier, which may support a narrower construction that excludes single, integrated detection algorithms.

’335 Patent: "a unit pixel"

  • The Term: "a unit pixel"
  • Context and Importance: This term in the preamble of Claim 1 defines the physical structure upon which the claimed method is performed. The analysis will turn on whether the accused Nikon sensors contain this specific structure.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: Plaintiffs may argue that "unit pixel" should be understood functionally as the smallest repeatable element of the sensor array that achieves the invention's purpose, and that the inventive concept is the sharing of output transistors between light-sensing areas, not a rigid definition requiring two photodiodes within a single pixel boundary.
    • Evidence for a Narrower Interpretation: The claim preamble explicitly recites that the "unit pixel... comprises a first photodiode... and a second photodiode." The specification consistently illustrates the "unit pixel" (400) as a single integrated structure containing two photodiodes (401, 402) (’335 Patent, Fig. 4; col. 4:60-65). This may support a construction requiring the presence of two photodiodes within what is defined as a single pixel.

VI. Other Allegations

Indirect Infringement

The complaint alleges both induced and contributory infringement for all three patents. Inducement allegations are based on Defendants’ creation and distribution of product literature, websites, and user manuals that allegedly instruct customers on how to use the infringing features (Compl. ¶¶47, 69, 92). Contributory infringement is based on the allegation that the accused software and image sensors are material components of the invention that are not staple articles of commerce suitable for substantial non-infringing use (Compl. ¶¶53, 75, 98).

Willful Infringement

The complaint alleges willful infringement based on Defendants’ alleged actual notice of the asserted patents or their direct predecessors. For the ’163 and ’335 patents, notice is alleged to have occurred via prior lawsuits filed in April 2017 (Compl. ¶¶48, 70). For the ’574 patent, notice is alleged based on the assertion of its parent patents in the same prior litigation and upon the ’574 patent’s issuance on August 8, 2017, prior to the filing of the instant case (Compl. ¶¶93, 100).

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

  • A core issue will be one of algorithmic mapping: Does Nikon's "Face Priority AF" feature, an integrated function in a consumer camera, perform the discrete, sequential steps of "correlating" to find a "local maximum" and then separately "screening" based on a "grayscale characteristic" as required by Claim 1 of the ’163 patent, or is there a fundamental mismatch in its technical operation?
  • A second key question will be one of architectural identity: Do Nikon's proprietary CMOS sensors employ the specific shared-component architectures required by the claims of the ’335 patent (multiple photodiodes sharing a single set of output transistors) and the ’574 patent (adjacent-row sensing nodes being electrically coupled during readout), or do they utilize a different design that is only functionally similar?
  • Finally, a central question for damages will be one of willfulness: Given the documented history of litigation between the parties involving the same patent families, what evidence will show whether Nikon's alleged infringement, if found, was undertaken with the knowledge and intent required to support a finding of willfulness and potential enhanced damages?