PTAB

IPR2018-00761

Shenzhen Silver Star Intelligent Technology Co., Ltd. v. iRobot Corporation

Title: Robot Obstacle Detection System
Brief Description: The ’308 patent describes a sensor subsystem for an autonomous robot. The system uses an optical emitter and a photon detector with intersecting fields of emission and view to detect the presence or absence of a surface, such as a floor, enabling the robot to avoid cliffs or other drop-offs by re-directing its path.

Prior Art Relied Upon: Everett (H.R. Everett, "Sensors for Mobile Robots Theory and Application" (1995)).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Everett, a foundational text on mobile robot sensors, discloses every element of the challenged claims. Everett’s ROBART II security robot was described as an autonomous robot using convergent-mode proximity sensors for floor discontinuity detection. These sensors employ a transmitting LED (emitter) and a detector whose optical axes are angled to intersect over a narrowly defined region. When the floor is no longer detected within this intersection region (e.g., at a descending stairway), an onboard processor is alerted, which disables the drive motors and re-directs the robot, thus anticipating the limitations of independent claim 1. Petitioner further asserted that Everett meets various dependent claims by disclosing the use of multiple sensors (claim 6), near-infrared technology (claim 8), and a "wall following" mode that constitutes an obstacle-following mode (claim 15).

Prior Art Relied Upon: WO '399 Application (International Publication No. WO 1993/003399).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner asserted that the WO '399 application, which predates the ’308 patent’s priority date, discloses an autonomous cleaning robot that anticipates the core claims. The reference describes a vacuum cleaner robot with downward-pointing drop-off sensors, each containing an LED emitter and a light detector. When the robot approaches a drop-off, light is no longer reflected to the detector, triggering a signal to the CPU that stops and reverses the robot's direction. This disclosure was argued to meet all limitations of claim 1. The WO '399 application also allegedly anticipates dependent claims by teaching multiple sensors spaced apart on the housing (claim 6), the use of infrared LEDs (claim 8), and placing sensors at the forward edge of the robot (claims 27, 32).

Prior Art Relied Upon: Everett (1995 book) and Jones (Joseph L. Jones and Anita M. Flynn, "Mobile Robots: Inspiration to Implementation" (1993)).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner contended that while Everett provides the base system, Jones—authored by the named inventor of the ’308 patent—explicitly teaches specific wall-following behaviors and cleaning features that render certain dependent claims obvious. Jones describes using infrared sensors for wall-following, including a "tacking" behavior where a robot arcs away from a wall upon detection and arcs back toward it when the wall is not detected, allegedly teaching the limitations of claims 3 and 4. Jones also discloses a floor-cleaning robot prototype with a brush, mapping to claim 7.
- Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) developing an autonomous robot like Everett’s would look to contemporaneous publications like Jones to implement well-known and beneficial functionalities. A POSITA would combine Jones's wall-following and cleaning teachings to improve the obstacle avoidance and utility of Everett's robot.
- Expectation of Success: Combining Jones's standard wall-following logic with Everett's sensor system would have been a straightforward application of known techniques with predictable results.

Prior Art Relied Upon: Everett (1995 book) and Schiller (Patent 5,245,177).
Core Argument for this Ground:
- Prior Art Mapping: Claim 11 recites a "collimator" for both the emitter and detector. Petitioner argued that Schiller, which discloses an electro-optical detection system, teaches this element. Schiller describes using a lens to create a collimated beam of light from an LED and using apertures to limit the detector's field of view, thereby teaching the claimed collimator structures.
- Motivation to Combine: A POSITA implementing Everett's sensor system, which relies on a "narrowly defined region" of intersection, would be motivated to use known optical techniques to precisely control the fields of emission and view. Schiller provides an express example of using collimating structures for this exact purpose in a similar detection system.
- Expectation of Success: Applying the known collimation techniques taught by Schiller to Everett's optical sensors would be a routine design choice to improve sensor precision and would produce predictable and improved results.
Additional Grounds: Petitioner asserted additional obviousness challenges based on other combinations of Everett, WO '399 Application, Jones, Schiller, and Immega (Patent 5,726,443), but relied on similar rationales for combining known wall-following, cleaning, and sensor collimation features.

"collimator" (claims 11, 12, 20): Petitioner proposed that "collimator" should be construed as a "structure through which light passes to bound the optical field of an emitter or a detector." Petitioner argued that while the term sometimes implies creating parallel beams, the ’308 patent’s specification uses it more broadly to include any structure that restricts or defines a field of view, such as simple tubes or apertures. This broader construction was asserted to be necessary for prior art like Schiller to meet the limitation.

Priority Date Challenge: Petitioner contended that the challenged claims are not entitled to the January 24, 2000 priority date of the parent provisional application. It was argued that the provisional application fails to provide adequate written description support for key limitations, including the emitter and detector fields that "intersect at a region" and the specific "re-directing" robot behavior. This would make the claims' effective filing date January 24, 2001, thereby rendering references like the WO '399 application (published in 1993) valid prior art.

Petitioner requests institution of an inter partes review and cancellation of claims 1-4, 6-8, 11-12, 14-15, 19-22, 25, and 27-34 of Patent 7,155,308 as unpatentable.