Microsoft Technology Licensing, LLC

Swati Mehta

Cyrus Soli Bamji

Tamer Elkhatib

Onur Can Akkaya

Satyadev Hulikal Nagaraja

Vijay Rajasekaran

Vei-Han Chan

Barry Thompson

Minseok Oh

Zhanping Xu

Andrew Dean Payne

William Qian

Tamer Ahmed Taha Elkhatib

An imaging system includes a sensor array of differential pixels. A controller operates a first differential pixel of the sensor array in a first, lower power mode. The controller supplies a first clock signal to selectively activate a first collection terminal of the first differential pixel for a first duration, and a second clock signal to selectively activate a second collection terminal of the first differential pixel for a second duration. In an analog domain, a first amount of charge accumulated at the first collection terminal over the first duration is readout and compared to a readout of a second amount of charge accumulated at the second collection terminal over the second duration. Responsive to the first amount of charge being different from the second amount of charge by more than a threshold, the first differential pixel of the sensor array is operated in a second, higher power mode.

Low power operation of differential image sensor pixels

Pixel arrangements in time-of-flight sensors are presented that include sensing elements that establish charges related to incident light, charge storage elements that accumulate integrated charges transferred from the sensing elements, and diffusion nodes configured to establish measurement voltages representative of the integrated charges that are dumped from the charge storage elements. The pixel arrangement includes analog domain output circuitry comprising a measurement capacitance element that stores the measurement voltage, and a reset capacitance element that stores a reset voltage established at the diffusion node during a reset phase performed prior to a measurement phase. The analog domain output circuitry subtracts the stored reset voltage from the stored measurement voltage for processing into a pixel output voltage that at least partially reduces readout voltage uncertainty of the pixel arrangement.

Readout voltage uncertainty compensation in time-of-flight imaging pixels

A time-of-flight detector includes a semiconductor layer and a light modulation structure. The semiconductor layer is configured to translate light radiation into electrical charge. The light modulation structure is configured to increase a path of interaction of light radiation through the semiconductor layer. In some example implementations, the light modulation structure is configured to deflect at least some light radiation at an increased angle through the semiconductor layer. In some example implementations, the light modulation structure is configured to reflect light radiation more than once through the semiconductor layer.

Quantum-efficiency-enhanced time-of-flight detector

A CMOS time-of-flight image sensor must be robust to interface traps and fixed charges which may be present due to fabrication and which may cause an undesired induced electric field in the silicon substrate. This undesired induced electrical field is reduced by introducing a hydrogen-enriched dielectric material. Further remedial techniques can include applying ultraviolet light and/or performing a plasma treatment. Another possible approach adds a passivation doping layer at a top of the detector as a shield against the undesired induced electric field. One or more of the above techniques can be used to prevent any unstable behavior of the time-of-flight sensor.

CMOS image sensor with a reduced likelihood of an induced electric field in the epitaxial layer

An imager includes an emitter, an array of pixel elements, and driver logic. The emitter releases bursts of light pulses with pauses between bursts. Each element of the array has a finger gate biasable to attract charge to the surface, a reading node to collect the charge, and a transfer gate to admit such charge to the reading node and to deter such charge from being absorbed into the finger gate. The driver logic biases the finger gates with the modulated light pulses such that the finger gates of adjacent first and second elements cycle with unequal phase into and out of a charge-attracting state. To reduce the effects of ambient light on the imager, the driver logic is configured to bias the transfer gates so that the charge is admitted to the reading node only during the bursts and is prevented from reaching the reading node during the pauses.

Burst-mode time-of-flight imaging

Embodiments of the present invention provide methods to produce a high performance, feature rich TOF system, phase-based or otherwise using small TOF pixels, single-ended or preferably differential, as well as TOF systems so designed. IC chip area required for pixels is reduced by intelligently off-loading or removing from within the pixel certain components and/or functionality. In some embodiments during a single TOF system capture period, analog values from each pixel are repeatedly sampled and converted to digital values, which are combined and manipulated on the sensor chip. Combining this plurality of values enables appropriately compact data from the sensor chip. Embodiments of the present invention implement a TOF system with high ambient light resilience, high dynamic range, low motion blur and dealiasing support, while advantageously reducing pixel area size relative to prior art TOF pixels.

System architecture design for time-of-flight system having reduced differential pixel size, and time-of-flight systems so designed

An analytical tool useable with complex systems receives as input various system parameters to predict whether sufficiently accurate quality depth data will be provided by the TOF system. Depth data quality estimates involve dividing system operation into smaller operations whose individual depth data quality contributions can be more readily computed. The effect of the individual operations is combined and the tool outputs a depth data quality estimate accounting for the net result of the various unique operations performed by the system. When used with a TOF system, input parameters may include magnitude and angular distribution of TOF emitted optical energy, desired signal/noise, sensor characteristics, TOF imaging optics, target object distances and locations, and magnitude of ambient light. Analytical tool output data can ensure adequate calculation accuracy to optimize the TOF system pre-mass production, even for TOF systems whose sequence of operations and sensor operations are flexibly programmable.

Method and system for noise simulation analysis useable with systems including time-of-flight depth systems

A CMOS-implementable TOF detector promptly collects charge whose creation time can be precisely known, while rejecting collection of potentially late arriving charge whose creation time may not be precisely known. Charges created in upper regions of the detector structure are ensured to be rapidly collected, while charges created in the lower regions of the detector structure, potentially late arriving charges, are inhibiting from being collected.

CMOS three-dimensional image sensor detectors with assured non collection of late arriving charge, more rapid collection of other charge, and with improved modulation contrast

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San Jose, CA, United States of America

Swati Mehta