Luminar Technologies, Inc.

Q-dot, Inc.

Prolume, Ltd.

Displaytech, Inc.

Luminar, LLC

Silicon Light Machines Corporation

Other

L-3 Communications Corporation

L-3 Communications Coporation

Black Forest Engineering, LLC

Stephen D Gaalema

Jason M Eichenholz

Thomas E Linnenbrink

Joseph G LaChapelle

Mark Anthony Wadsworth

Scott R Campbell

Austin K Russell

Bruce J Bryan

Randall B Murphy

Mark A Handschy

Tue Tran

Douglas Webb

Stephen L Mielke

Mark A Drummer

Alexander P Payne

Matthew D Weed

Charles M Hanson

Lane A Martin

Alain Villeneuve

Rodger W Cleye

Josef Berger

David W Gardner

John F Brady

David Dobyns

Robert D Still

Gary Lee Kline

William Bahn

A receiver of a lidar system configured to receive one or more scattered light pulses from a target in a field of regard of the lidar system. The receiver includes a detector that emits an electric signal representative of the received light pulse in response to detecting the received light pulse. The receiver further includes one or more analog circuits configured to receive the electric signal from the detector, sample one or more voltages of the electric signal, and determine the energy of the received light pulse based at least on the one or more sampled voltages. The lidar system may further calculate a reflectivity and/or other characteristics of the target based at least on the energy of the received light pulse.

Circuit for measuring pulse energy in a lidar system

Amplifier input protection circuits are described. In one embodiment, a photoreceiver for a lidar system has a photodetector configured to generate an output current in response to received light. A transimpedance amplifier is configured to receive the output current and generate a voltage output corresponding to the output current in response thereto, and a diode circuit has a cathode coupled at a node between the photodetector output and the transimpedance amplifier input.

Amplifier input protection circuits

In one embodiment, a lidar system includes a light source configured to emit multiple optical signals directed into a field of regard of the lidar system. The optical signals include a first optical signal and a second optical signal, where the second optical signal is emitted a particular time interval after the first optical signal is emitted. The lidar system also includes a receiver configured to detect a received optical signal that includes a portion of the emitted first or second optical signal that is scattered by a target located a distance from the lidar system. The received optical signal is detected after the second optical signal is emitted. The receiver includes a first detector configured to detect a first portion of the received optical signal and a second detector configured to detect a second portion of the received optical signal.

Lidar receiver with multiple detectors for range-ambiguity mitigation

A circuit for quenching an avalanche photodiode (APD) detector is disclosed herein. The circuit may comprise a discrete transistor configured to draw a quench current so as to enable a drop in a reverse bias voltage applied to the APD detector, and an integrated circuit connected to the discrete transistor, the integrated circuit including a plurality of circuit elements for controlling the reverse bias voltage.

Detector quench circuit for lidar system comprising a discrete transistor to draw a quench current to enable a drop in a reverse bias voltage applied to an avalanche photodiode

A lidar system includes a light source configured to emit light pulses and a receiver configured to detect light from some of the light pulses scattered by remote targets. The receiver includes an avalanche photodiode operating in the linear mode for detecting the light pulses. To prevent damage to the linear mode avalanche photodiode a quench circuit is coupled to the avalanche photodiode, where the quench circuit reduces a bias voltage applied to the avalanche photodiode, when an avalanche event occurs at the avalanche photodiode.

Method for controlling peak and average power through laser receiver

To decrease the likelihood of a false detection when detecting light from light pulses scattered by remote targets in a lidar system, a receiver in the lidar system includes a photodetector and a pulse-detection circuit having a gain circuit with a varying amount of gain over time. The gain circuit operates in a low-gain mode for a time period Tbeginning with time twhen a light pulse is emitted to prevent the receiver from detecting return light pulses during the threshold time period T. Upon expiration of the threshold time period T, the gain circuit operates in a high-gain mode to begin detecting return light pulses until a subsequent light pulse is emitted.

Time varying gain in an optical detector operating in a lidar system

In one embodiment, a lidar system includes a light source configured to emit pulses of light and a scanner configured to scan at least a portion of the emitted pulses of light across a field of regard. The lidar system also includes a receiver configured to detect at least a portion of the scanned pulses of light scattered by a target located a distance from the lidar system.

Lidar system

A scanning system includes a light source configured to emit light as a series of one or more light pulses, a scanner configured to direct the one or more light pulses towards a remote target, and a receiver configured to detect light scattered by the remote target. The receiver includes a light detector element disposed on an ASIC that includes multiple comparators disposed in parallel with one another, and corresponding time-to-digital converters (TDCs) coupled to the comparator. Each of the comparators processes a received electrical signal from the light detector element to produce a digital edge signal when the amplitude of the received electrical signal reaches a particular threshold. A corresponding TDC outputs a time delay value associated with a time at which the received electrical signal reaches the particular threshold.

Lidar detector having a plurality of time to digital converters integrated onto a detector chip

In one or more embodiments, an apparatus and method for processing an analog signal into a digital signal includes an input current buffer circuit, a signal charge integration node, a dual function comparator, a step charge subtractor, a state latch, a coarse N-bit counter, an optional residue signal buffer and a residue signal M-bit time-to-digital (TDC) converter. The circuitry is free running, meaning that it is never reset. Instead, what is tracked for each frame is how much additional charge has been accumulated since the end of the previous integration period. Between each frame, the state of the counter and the amount of charge residing in the integration node are recorded. This information from the beginning and end of a given frame is differenced and to this is added the amount of charge indicated by the number of times the counter overflowed during the integration period.

Low power ADC for high dynamic range integrating pixel arrays

Read-out cell systems are disclosed for image detectors, including infrared image detectors, that provide improved sensitivity by providing in-cell subtraction through the use of a voltage ramp signal generated using a reference pixel and a feedback amplifier. The ramp voltage is generated using a reference pixel and an amplifier having feedback. The ramp voltage is then provided to a plurality of read-out cells. The ramp voltage can be coupled to an input transistor to provide current subtraction prior to the integration node. The ramp voltage can also be provided to integration capacitors within the read-out cells to provide current subtraction directly to the integration node. Further, a temperature-independent fixed current source can also be utilized to further control current subtraction.

In-cell current subtraction for infrared detectors

A driver is provided for use with a MEMS device. Generally, the driver includes: (i) a high voltage circuit electrically coupled to a movable actuator of the MEMS to apply a HV pulse thereto; and (ii) a charge control circuit coupled to a base electrode formed in a substrate underlying the actuator to control a potential applied to the base electrode. The charge control circuit can include a capacitance divider having a plate capacitor defined by the actuator and the base electrode, and a charge storage capacitor electrically coupled to the base electrode and in series with the plate capacitor. The charge storage capacitor can include a variable, voltage controlled capacitor, the capacitance of which is controlled by an input signal or voltage to the driver. Other embodiments are also disclosed.

High impedance drive circuit for a micro-electromechanical system device

An integrating capacitor circuit for an integrating amplifier and related methods are disclosed that allow for efficient detection of currents or charges, particularly those produced by pixel cells in a detector image array. By placing a capacitor-connected field-effect-transistor (FET) in parallel with an integration capacitor and setting its gate voltage to a selected voltage level, the current or charge from the detector depletes the charge on the gate of the FET capacitor while integrating on the capacitor. In addition, the gate voltage level can be adjusted to modify the current depleting characteristics of the capacitor-connected FET. The resulting operation of this integrating circuitry provides significant resulting advantages for the integrating amplifier.

Integrating capacitance circuitry for an integrating amplifier and related method

In one embodiment, a micro electromechanical system (MEMS) driver circuit receives a pulse-width modulated (PWM) signal and uses it to control a voltage at a MEMS cell. The driver circuit further includes a current source, a capacitor, and a reset circuit that can discharge the capacitor. The voltage at the MEMS cell can be controlled in proportion to the pulse width of the PWM signal. In another embodiment disclosed, a MEMS driver circuit receives a first PWM signal and a second PWM signal. Each PWM signal is coupled to a current source. One current source can provide a course current control and the other current source can provide fine current control. The driver circuit can further include a capacitor and a reset circuit for discharging the capacitor. The voltage at the MEMS cell can be controlled in proportion to a summation of the first and second current sources. According to another aspect of the embodiments, a method of controlling a voltage at a MEMS cell is disclosed. The method includes the steps of receiving a PWM signal, controlling a current source with the PWM signal, and adjusting the voltage at the MEMS cell in proportion to a pulse width of the PWM signal.

Growing community of inventors

Colorado Springs, CO, United States of America

Stephen D Gaalema