Hesai Technology Co Ltd v. Ouster Inc

1. Case Identification

• Case #: IPR2023-01457
• Patent #: 11,190,750
• Filed: September 25, 2023
• Petitioner(s): Hesai Technology Co. Ltd.
• Patent Owner(s): Ouster, Inc.
• Challenged Claims: 44-48 and 50

2. Patent Overview

• Title: Optical Imaging System with a Plurality of Sense Channels
• Brief Description: The ’750 patent discloses a LiDAR (Light Detection and Ranging) system for collecting distance information. The system comprises a transmit section with multiple illumination sources and a receive section that uses a plurality of pixels, where each pixel may be an array of single-photon avalanche diodes (SPADs), to detect photons reflected from objects in the field.

3. Grounds for Unpatentability

Ground 1A: Claims 44, 45, 48, and 50 are obvious over Retterath and Borowski

• Prior Art Relied Upon: Retterath (Patent 10,203,399) and Borowski (Application # 2013/0300838).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Retterath taught a multi-beam LiDAR system with the core components of independent claim 44, including a bulk imaging optic, a detector array arranged behind the optic, a bulk transmitting optic adjacent to the imaging optic, and a plurality of emitters. Retterath’s system was designed with non-overlapping fields of view for each detector and coincident emitter-detector axes to reduce crosstalk. Petitioner contended that Borowski taught the benefit of implementing each detector pixel in a LiDAR array as a "macro-cell" containing a plurality of SPADs. The combination of Retterath’s architecture with Borowski’s multi-SPAD pixel design allegedly rendered claim 44 obvious. Dependent claims 45 (additional pixels/apertures), 48 (photon counting), and 50 (distance data collection) were argued to be obvious for similar reasons.
  • Motivation to Combine: A POSITA would combine Borowski’s multi-SPAD pixel teaching with Retterath’s LiDAR system for several predictable benefits. These included enhancing the signal-to-noise ratio (SNR) due to the high sensitivity of SPADs, improving detection accuracy by mitigating the effects of individual SPAD quenching and reset times, achieving a better trade-off between image depth resolution and data acquisition speed, and gaining known performance advantages like high data rates and low-power operation. Petitioner asserted this was an application of a known technique to a known system to achieve predictable results.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because both Retterath and Borowski described analogous LiDAR systems and addressed common design challenges, making the integration of Borowski's improved detector into Retterath's system straightforward.

Ground 1B: Claims 44-48 and 50 are obvious over Retterath, Borowski, and Weimer

• Prior Art Relied Upon: Retterath (Patent 10,203,399), Borowski (Application # 2013/0300838), and Weimer (Patent 8,736,818).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the Retterath-Borowski combination from Ground 1A, adding Weimer to teach limitations recited in the dependent claims. Specifically, Weimer taught a vehicle-based LiDAR system and expressly suggested using vertical-cavity surface-emitting lasers (VCSELs) as emitters (mapping to claim 46) and using a single VCSEL per emitter (mapping to claim 47). Weimer also taught matching the field-of-view of a detector pixel to the emission pattern of its corresponding laser beam, which further supported the "coincident" field of view limitation in claim 44.
  • Motivation to Combine: A POSITA would have been motivated to incorporate Weimer’s teachings into the Retterath-Borowski system to further improve performance. Using VCSELs, as taught by Weimer, was a known method for achieving precise, well-delineated beam profiles and improved efficiency. Further, matching the detector’s field-of-view to the emitter’s spot size, also taught by Weimer, was a known technique to improve SNR by reducing the detection of background light and interference.
  • Expectation of Success: The combination was argued to be a predictable implementation of known, compatible technologies. VCSELs were known to integrate readily into LiDAR emitter arrays like the one disclosed in Retterath.

Ground 2: Claims 44-48, 50 are obvious over Imai, Higashi, and Grzesik

• Prior Art Relied Upon: Imai (Application # 2016/0274223), Higashi (JP Publication No. JP 2015-078953), and Grzesik (Application # 2017/0040368).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued this alternative combination also rendered the claims obvious. Imai taught a scanning laser radar system with a laser diode array, a photodiode array, and corresponding bulk optics. Higashi was cited for its teaching of using multiple SPADs for each detector pixel to reduce erroneous detections and improve accuracy. Grzesik was cited for teaching an aperture layer (a "cross talk absorption layer") comprising a plurality of apertures over a photodiode array to block stray light and reduce optical crosstalk between pixels.
  • Motivation to Combine: A POSITA would first combine Higashi's multi-SPAD pixel design into Imai's LiDAR system to achieve the known benefits of improved sensitivity and reduced detection errors. Subsequently, a POSITA would be motivated to add Grzesik's aperture layer to the combined Imai-Higashi system to address the well-known problem of optical crosstalk in detector arrays, thereby further improving resolution and signal integrity.
  • Expectation of Success: Petitioner argued a POSITA would have a high expectation of success, as all three references operated in the same technical field and provided solutions to known, persistent problems in LiDAR design.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations of Retterath, Borowski, and Hipp (Ground 1C); Retterath, Borowski, Weimer, and Hipp (Ground 1D); and Weimer, Borowski, and Hipp (Ground 3), which relied on similar motivations to combine to reduce crosstalk and improve system performance.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial would be inappropriate under both §314(a) and §325(d). Regarding the Fintiv factors, Petitioner noted that the parallel district court litigation was stayed and an related ITC investigation had been terminated, making it highly unlikely that either forum would resolve invalidity before the Board could issue a Final Written Decision (FWD). Regarding §325(d), Petitioner asserted that the petition raised new grounds based on prior art and arguments that were materially different from those considered by the examiner during prosecution, as none of the primary references like Borowski, Weimer, Imai, or Higashi were substantively applied in any office action rejection.

5. Relief Requested

• Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 44-48 and 50 as unpatentable.