STMICROELECTRONICS (RESEARCH & DEVELOPMENT) LIMITED

This disclosure relates to a time-of-flight sensor including, on a same base substrate, a light emitter configured to emit light into an image scene, a reference sensor configured to detect light emitted by the light emitter, and a signal reception sensor array separated from the light emitter by an optical barrier. The optical barrier is configured to prevent light emitted by the light emitter from directly reaching the signal reception sensor array, with the signal reception sensor array being configured to detect light reflected by the image scene. The reference sensor and the signal reception sensor array are based on semiconductor nanoparticles.

An optical element is positioned in a holder over a laser light source. The optical element includes an electrical trace that is coupled between first and second pads. A sensing circuit that is also coupled to the first and second pads performs a voltage/current sensing operation to detect displacement of the optical element and control enablement of the laser light source.

A differential correlator filter includes: a pre-pulse region, where first filter coefficients in the pre-pulse region have negative values; and a pulse region including: a rising edge region adjacent to the pre-pulse region, where second filter coefficients in the rising edge region have positive values; an accumulation region adjacent to the rising edge region, where third filter coefficients of the accumulation region have positive values; and a falling edge region adjacent to the accumulation region, where fourth filter coefficients of the falling edge region have positive values, where the accumulation region is between the rising edge region and the falling edge region. The differential correlator filter further includes a post-pulse region adjacent to the pulse region, where the pulse region is between the pre-pulse region and the post-pulse region, where fifth filter coefficients of the post-pulse region have negative values.

Various embodiments provide optical lenses that include phase shift layers that transmit incident light with four or more distinct phase quantizations. In one embodiment, a lens includes a substrate, a first immersion material layer on the substrate, and a plurality of anti-reflective phase shift layers on the first immersion material layer. The phase shift layers define a first anti-reflective phase shift region that transmits received light without a phase shift, a second anti-reflective phase shift region configured to transmit the received light with a first phase shift, a third anti-reflective phase shift region configured to transmit the received light with a second phase shift, and a fourth anti-reflective phase shift region configured to transmit the received light with a third phase shift. The first, second, and third phase shifts are different from one another.

A method can be used to detect the presence an object within a field of view of a time-of-flight sensor. A histogram generated by the time-of-flight sensor is obtained. The histogram includes a number of bins associating a number of detected photons to a given acquisition time. A portion of the bins of the histogram is transformed into points in a transformed domain that features a first area containing only points associated to bins representative of the presence of the object and a second area having only points associated to bins not representative of the presence of the object. The bins of the histogram representative of the presence of the object are identified from the points located in the first area.

The present disclosure is directed to a sensor that detects a distance between the sensor and a target object. The sensor includes a transmission optical structure and/or a light source that polarizes light and minimizes cross talk within the sensor. As a result, detection results of the sensor are improved.

An array of single photon avalanche diodes (SPADs) includes a plurality of pixels. Each pixel includes a SPAD having a cathode connected to a first intermediate node and an anode coupled to first negative voltage, a quench circuit connected between the first intermediate node and the low voltage supply node, an AC coupling element connected between the first intermediate node and a second intermediate node, a filter component connected between the high voltage node and the second intermediate node, and an inverter having its input connected to the second intermediate node and its output providing an output signal. A resistance associated with the quench circuit, a capacitance associated with the SPAD, a capacitance associated with the AC coupling element, and a resistance associated with the filter component form a variable second order filter.

Disclosed herein is a single photon avalanche diode (SPAD) pixel for use in time-of-flight imaging. This pixel includes a SPAD having a cathode connected to a first node and an anode coupled to first negative voltage. A transistor circuit in the pixel includes a quench transistor connected between a supply voltage node and a second node, the quench transistor controlled by a quench control signal to operate in a high-impedance mode, and a recharge transistor connected in parallel with the quench transistor between the supply voltage node and the second node, the recharge transistor controlled by a feedback signal. The pixel also includes a readout inverter generating an output signal based upon a voltage at the first node and an adjustable delay circuit generating the feedback signal based upon the output signal, the feedback signal being delayed with respect to the output signal.

A time-of-flight system includes an emitter-circuit generating and directing pulses of light toward a target, and a receiver-circuit including a photodetector coupled between a bias node and a sensing node to detect pulses that have reflected off the target, a comparison circuit comparing a sense voltage at the sensing node to a reference, a timing measurement circuit measuring elapsed time between generation of a given pulse and detection thereof after reflection off the target, and a programmable current sink that sinks a current from the sensing node equal to a portion of a photocurrent generated by the photodetector due to detection of ambient light. A timing-generation circuit synchronizes generation of the pulses and measurement of elapsed time by the timing circuit. A processor adjusts a magnitude of the current sunk from the sensing node based upon output of the comparison circuit when the emitter circuit is deactivated.

Various embodiments provide optical lenses that include phase shift layers that transmit incident light with four or more distinct phase quantizations. In one embodiment, a lens includes a substrate, a first immersion material layer on the substrate, and a plurality of anti-reflective phase shift layers on the first immersion material layer. The phase shift layers define a first anti-reflective phase shift region that transmits received light without a phase shift, a second anti-reflective phase shift region configured to transmit the received light with a first phase shift, a third anti-reflective phase shift region configured to transmit the received light with a second phase shift, and a fourth anti-reflective phase shift region configured to transmit the received light with a third phase shift. The first, second, and third phase shifts are different from one another.