Ranging Optics LLC v. Nikon Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Ranging Optics LLC (Texas)
  • Defendant: Nikon Inc. (New York)
  • Plaintiff’s Counsel: Insight, PLC; Ni, Wang & Massand, PLLC
• Case Identification: 2:20-cv-11658, C.D. Cal., 12/28/2020
• Venue Allegations: Plaintiff alleges venue is proper because a substantial part of the events giving rise to the claims occurred in the district, Defendant has committed acts of infringement in the district, and Defendant has a regular and established place of business in the district.
• Core Dispute: Plaintiff alleges that Defendant’s laser range finder products infringe patents related to a light receiving circuit for signal processing and a signal detector for identifying abnormal data transmissions.
• Technical Context: The technology concerns the electronic circuitry within optical devices like laser range finders, focusing on improving signal-to-noise ratio and ensuring reliable data transmission.
• Key Procedural History: The complaint does not mention any prior litigation, IPR proceedings, or licensing history related to the asserted patents. The U.S. Patent No. 7,443,927 is a continuation-in-part of a now-abandoned application.

Case Timeline

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

U.S. Patent No. 6,512,574 - "Light Receiving Circuit of Laser Range Finder," Issued January 28, 2003

The Invention Explained

• Problem Addressed: The patent describes that in traditional laser range finders, the accuracy of distance measurement is degraded by noise, which can interfere with the time delay calculation of the reflected laser pulse. This problem is exacerbated as the measurement distance increases (Compl. ¶19; ’574 Patent, col. 1:23-28).
• The Patented Solution: The invention claims to solve this problem with a specific circuit architecture. It uses a "bias stabilized main amplifier" followed by a "one-shot circuit" to process the signal from a photosensitive element (’574 Patent, col. 1:42-45). The bias stabilization is intended to prevent signal drift, and the one-shot circuit shapes the amplified signal into a clean digital pulse with a fixed width, thereby improving the signal-to-noise ratio and enabling more sensitive detection (’574 Patent, col. 1:45-50).
• Technical Importance: This approach aimed to increase the maximum effective range and sensitivity of laser range finders by creating a more stable and reliable signal processing path for weak, reflected laser signals (’574 Patent, col. 1:48-50).

Key Claims at a Glance

• The complaint asserts independent Claim 7 (Compl. ¶29).
• The essential elements of Claim 7 are:
  • A light receiving circuit of a laser range finder, comprising:
  • a photosensitive element for converting a light signal into a current signal;
  • a conversion amplifier connected with said photosensitive element for converting the current signal into a voltage signal;
  • a main amplifier connected with the conversion amplifier for amplifying the output voltage signal;
  • a one-shot circuit connected with the main amplifier for shaping the output voltage signal into a digital signal by which the range-finding computation is attained;
  • wherein said main amplifier is a bias stabilized amplifier.
• The complaint reserves the right to assert other claims during discovery (Compl. ¶3).

U.S. Patent No. 7,443,927 - "Signal Detector," Issued October 28, 2008

The Invention Explained

• Problem Addressed: The patent identifies shortcomings in signal transmission systems that lack a detection function. An interruption to a clock signal can halt transmission without warning, and a short circuit can cause a continuous, abnormal stream of data signals, potentially exhausting or damaging system components like a laser (Compl. ¶25; ’927 Patent, col. 1:22-32).
• The Patented Solution: The invention discloses a signal detector designed to identify these specific fault conditions. It comprises a signal translator, data and clock signal detectors, and an "interrupting control circuit" (’927 Patent, col. 1:36-40). This control circuit is designed to receive a detecting signal and output a shutdown signal when it identifies an abnormality, such as when a data signal remains at a high voltage "over a predefined ratio" or when a clock signal disappears (’927 Patent, col. 1:43-46, col. 5:5-8).
• Technical Importance: This technology provides a protective mechanism for data transmission systems, particularly in optical applications, by actively monitoring for signal integrity and initiating a shutdown to prevent damage and wasted resources.

Key Claims at a Glance

• The complaint asserts independent Claim 1 (Compl. ¶35).
• The essential elements of Claim 1 are:
  • A signal detector, comprising:
  • a signal translator converting differential data signals into a single data signal;
  • a data signal detector outputting a data detecting signal according to the single data signal; and
  • an interrupting control circuit receiving the data detecting signal and outputting a shutdown signal when the single data signal is at high voltage level over a predefined ratio.
• The complaint reserves the right to assert other claims during discovery (Compl. ¶3).

III. The Accused Instrumentality

Product Identification

The complaint identifies the Nikon Monarch 3000 Stabilized laser range finder as an exemplary accused product (Compl. ¶2).

Functionality and Market Context

The complaint alleges the accused product is a laser range finder that contains infringing circuitry for receiving and processing light signals (Compl. ¶30). The infringement allegations are supported by teardown photographs of the product's internal circuit board, identifying specific components alleged to perform the claimed functions, such as an Avalanche Photodiode (APD), a TC75S51F chip, an LMV7219 Comparator, and an STM32F103C8T6 microcontroller (Compl. ¶¶30, 36). The complaint provides an image showing the internal circuit board of the accused product (Compl. p. 9). The complaint does not provide specific details on the product's market positioning beyond its general function as a laser range finder.

IV. Analysis of Infringement Allegations

’574 Patent Infringement Allegations

Identified Points of Contention

• Technical Question: A central question will be whether the combination of the "TC75S51F Chip" and its associated "plurality of capacitors and resistors" in the accused product performs the function of a "bias stabilized amplifier" as described in the patent. The patent teaches a specific stabilization loop and a low-pass filter feedback mechanism (’574 Patent, col. 2:32-44). The case may turn on whether the accused circuitry operates in the same way.
• Scope Question: The claim requires a "one-shot circuit" that shapes the signal "into a digital signal by which the range-finding computation is attained." The complaint alleges a comparator and an ADC perform this function. A dispute may arise over whether this multi-component arrangement meets the "one-shot circuit" limitation as understood from the patent's disclosure.

’927 Patent Infringement Allegations

Identified Points of Contention

• Scope Question: The claim requires the shutdown signal to be triggered when the data signal is at a high voltage "over a predefined ratio." The complaint alleges an "Interrupt service routine" performs this function based on the "voltage of the data detecting signal." A key dispute will be whether this software-based voltage monitoring meets the "predefined ratio" limitation, which the patent specification links to a signal being at a high logic level for a certain number of bits or period of time (’927 Patent, col. 4:1-9).
• Technical Question: What evidence does the complaint provide that the accused STM32F103C8T6 microcontroller actually executes an "Interrupt service routine" that functions as claimed? The allegation is conclusory and will likely require significant discovery and potentially reverse engineering to substantiate.

V. Key Claim Terms for Construction

’574 Patent: "bias stabilized amplifier" (Claim 7)

Context and Importance

This term is the final, qualifying limitation of Claim 7 and appears central to the patent's novelty. The infringement allegation rests on the argument that a main amplifier connected to capacitors and resistors meets this limitation. Its construction will determine whether a general-purpose amplifier with biasing components infringes, or if a more specific circuit structure is required.

Intrinsic Evidence for Interpretation

• Evidence for a Broader Interpretation: The claim language itself is relatively broad, not specifying the exact mechanism of stabilization. A party might argue that any amplifier circuit designed to maintain a stable DC bias point meets the plain meaning of the term.
• Evidence for a Narrower Interpretation: The specification describes a specific "bias stabilization loops 33" which includes a feedback path from the amplifier's output back to its input via a "low pass filter 35" (’574 Patent, col. 2:32-44, Fig. 2). A party could argue this disclosed embodiment limits the claim's scope to amplifiers using a similar feedback filter structure for stabilization.

’927 Patent: "over a predefined ratio" (Claim 1)

Context and Importance

This term defines the condition that triggers the "interrupting control circuit." Its meaning is critical for infringement, as the plaintiff must prove not only that the accused device can issue a shutdown signal, but that it does so based on this specific "ratio." Practitioners may focus on this term because terms of degree can be susceptible to indefiniteness challenges.

Intrinsic Evidence for Interpretation

• Evidence for a Broader Interpretation: A party might argue "ratio" should be interpreted broadly to mean any proportional condition, such as the input voltage exceeding a threshold for a certain amount of time, as alleged in the complaint. The specification discusses the signal being at a "high voltage level over the predefined ratio or over the predefined period" (’927 Patent, col. 3:4-6), suggesting "period" is one way to define the "ratio."
• Evidence for a Narrower Interpretation: The specification provides a more concrete example: "During period P2, single data signal S1 is logic 1 (high voltage level) for 800 bits," which causes the integrating signal to cross a threshold (’927 Patent, col. 4:2-9). A party could argue "ratio" requires a comparison of high-logic-level time to total time, or a comparison of bit counts, rather than just exceeding a voltage threshold for a generic duration.

VI. Other Allegations

Indirect Infringement

The complaint makes general allegations of induced and contributory infringement (Compl. ¶5), but does not plead specific facts to support the knowledge and intent elements required for such claims, such as referencing user manuals or other materials that instruct customers to use the product in an infringing manner.

Willful Infringement

The complaint requests enhanced damages for willful infringement in its prayer for relief (Compl. p. 22, ¶B). The basis for this allegation appears to be post-suit conduct, as the complaint alleges infringement and inducement "at least as early as the filing and/or service of this Complaint" (Compl. ¶5), without pleading facts supporting pre-suit knowledge of the patents or infringement.

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

This dispute centers on whether the off-the-shelf and general-purpose components identified in the accused Nikon range finder perform the specific, specialized functions recited in the patent claims. The key questions for the court will likely be:

1. A core issue will be one of technical operation: Does the accused product's main amplifier, which is connected to standard biasing components, function as the "bias stabilized amplifier" taught in the ’574 Patent, which discloses a specific feedback loop and low-pass filter to achieve stabilization?
2. A second central issue will be one of definitional scope: Can the term "over a predefined ratio" from the ’927 Patent be construed to cover the alleged function of an "Interrupt service routine" that monitors voltage levels in a microcontroller? The case may turn on what evidence is required to prove that the accused software operates based on a "ratio" as contemplated by the patent, rather than a simple voltage threshold check.
3. A key evidentiary question for both patents will be one of functional specificity: Can the plaintiff demonstrate, beyond the use of datasheets for general-purpose components, that the accused circuitry is actually configured and operates to meet the specific functional limitations of the claims, such as the "one-shot circuit" limitation of the ’574 patent and the "interrupting control circuit" logic of the ’927 patent?