Mesa Imaging Ag

Ams Sensors Singapore Pte. Ltd.

Heptagon Micro Optics Pte. Ltd.

Csem Centre Suisse D'electronique Et De Microtechnique Sa

Michael Lehmann

Bernhard Buettgen

Thierry Oggier

Miguel Bruno Vaello Paños

Rolf Kaufmann

Bassam Hallal

Daniel Pérez Calero

Stephan Beer

Jonas Felber

Simon Neukom

Jens Kubacki

Jim Lewis

Peter Seitz

Bernhard Büttgen

Max Erick Busse-Grawitz

Felix Lustenberger

Guy Voirin

Kaspar Cottier

Rino E Kunz

Sophie Godé

Sophie GodÉ

Miguel Bruno Vaello PAÑOS

PÉREZ Daniel Calero

Bruno Vaello

An optoelectronic module including a light emitter to generate light to be emitted from the module; a plurality of spatially distributed light sensitive elements arranged to detect light from the emitter that is reflected by an object outside the module; and one or more dedicated spurious-reflection detection pixels.

Optoelectronic modules operable to recognize spurious reflections and to compensate for errors caused by spurious reflections

An optoelectronic module including a light emitter to generate light to be emitted from the module, a plurality of spatially distributed light sensitive elements arranged to detect light from the emitter that is reflected by an object outside the module, and one or more dedicated spurious-reflection detection pixels.

Time-of-flight (TOF) based systems using light pulse compression are described and, in some cases, can help increase demodulation contrast. Further, light pulse shaping techniques are described that, in some cases, can help reduce phase non-linearity and distance-calculation errors. The techniques can be used, for example, in measurement systems, as well as imaging systems in which a time-of-flight and/or distance information is obtained. The time-of-flight and/or distance information can be used to reconstruct and display a three-dimensional image of a scene. The light compression techniques also can be used to provide reference signals.

Time-of-light-based systems using reduced illumination duty cycles

Optoelectronic modules () are operable to distinguish between signals indicative of reflections from an object of interest and signals indicative of a spurious reflection. Various modules are operable to recognize spurious reflections by means of dedicated spurious-reflection detection pixels () and, in some cases, also to compensate for errors caused by spurious reflections.

The present disclosure describes optical imaging and optical detection modules that include sensors such as time-of-flight (TOF) sensors. Various implementations are described that, in some instances, can help reduce the amount of optical cross-talk between active detection pixels and reference pixels and/or can facilitate the ability of the sensor to determine an accurate phase difference to be used, for example, in distance calculations.

Optical imaging modules and optical detection modules including a time-of-flight sensor

A demodulation pixel improves the charge transport speed and sensitivity by exploiting two effects of charge transport in silicon in order to achieve the before-mentioned optimization. The first one is a transport method based on the CCD gate principle. However, this is not limited to CCD technology, but can be realized also in CMOS technology. The charge transport in a surface or even a buried channel close to the surface is highly efficient in terms of speed, sensitivity and low trapping noise. In addition, by activating a majority carrier current flowing through the substrate, another drift field is generated below the depleted CCD channel. This drift field is located deeply in the substrate, acting as an efficient separator for deeply photo-generated electron-hole pairs. Thus, another large amount of minority carriers is transported to the diffusion nodes at high speed and detected.

Demodulation pixel incorporating majority carrier current, buried channel and high-low junction

A novel photo-sensitive element for electronic imaging purposes and, in this context, is particularly suited for time-of-flight 3D imaging sensor pixels. The element enables charge-domain photo-detection and processing based on a single gate architecture. Certain regions for n and p-doping implants of the gates are defined. This kind of single gate architecture enables low noise photon detection and high-speed charge transport methods at the same time. A strong benefit compared to known pixel structures is that no special processing steps are required such as overlapping gate structures or very high-ohmic poly-silicon deposition. In this sense, the element relaxes the processing methods so that this device may be integrated by the use of standard CMOS technology for example. Regarding time-of-flight pixel technology, a major challenge is the generation of lateral electric fields. The element allows the generation of fringing fields and large lateral electric fields.

PN-structured gate demodulation pixel

A pixel is formed in a semiconductor substrate (S) with a plane surface for use in a photodetector. It comprises an active region for converting incident light (In) into charge carriers, photogates (PGL, PGM, PGR) for generating a lateral electric potential (&#x3a6;(x)) across the active region, and an integration gate (IG) for storing charge carriers generated in the active region and a dump site (Ddiff). The pixel further comprises separation-enhancing means (SL) for additionally enhancing charge separation in the active region and charge transport from the active region to the integration gate (IG). The separation-enhancing means (SL) are for instance a shield layer designed such that for a given lateral electric potential (&#x3a6;(x)), the incident light (In) does not impinge on the section from which the charge carriers would not be transported to the integration gate (IG).

Solid-state photodetector pixel and photodetecting method

A demodulation image sensor, such as used in time of flight (TOF) cameras, extracts all storage- and post-processing-related steps from the pixels to another array of storage and processing elements (proxels) on the chip. The pixel array has the task of photo-detection, first processing and intermediate storage to create subframes, while the array of storage and processing elements provides accumulation into frames. Particularly, sampled values of several subframes are summed in a compressed manner. Possible compression is to use exponential function.

Time of flight sensor with subframe compression and method

A high-speed, high-sensitivity demodulation sensor usable for e.g. time-of-flight application uses a back side illuminated (BSI) image sensor chip, in which the photo-generated charges are first transferred to a demodulation area, from which the charges are then sampled and stored on at least one specific storage node. The storage node is electrically isolated from the sensitive area. Such a pixel might find its use specifically in 3D time-of-flight imaging given its improvements in sensitivity because the presented invention allows to design pixel with up to 100% fill factor and enables charge detection even if the charge generation by the photon occurs deep in the silicon substrate.

Demodulation pixel with backside illumination and charge barrier

The presented readout structure provides charge transport based readout of a photosensitive device with a minimum number of transport gates. The structure uses the given charge storage buckets of the photosensitive device, separated by a minimum sized barrier-gate, to transport the charge out of the pixel field. This new readout schema allows for a fast readout speed based on a 2 phase transport chain and increases the pixel's optical fill factor by significantly reducing the transport gate size compared to state-of-the-art pixels using a 3 or 4 phase CCD readout chain. This readout structure can be exploited for standard photo-detecting elements such as e.g. pinned photo-diodes or any enhanced pixel structure that has additional intelligence incorporated as well. Typical applications are 2D- or 3D-imaging. The process used for manufacturing a sensor with such a readout scheme requires preferably charge transport mechanisms like charge-coupled gate devices as well as the possibility of integrating circuitries of high density. The exploitation of such a combination of process-related features results in a new sensor readout technique that allows for optimizing the pixel's dynamic range and optical fill factor.

3D CCD-style imaging sensor with rolling readout

An increased sense node capacitance, mainly for 3D time-of-flight (TOF) applications, includes a storage structure that combines the advantages of gate and diffusion capacitance in order to improve the overall capacitance. The storage structure provides higher capacitance per unit area and accordingly a better fill-factor/sensitivity of the pixel; improved noise behaviour because of the use of gate capacitances, better protection against interacting signals and thus better signal quality.

Sense node capacitive structure for time of flight sensor

A demodulation pixel architecture allows for demodulating an incoming modulated electromagnetic wave, normally visible or infrared light. It is based on a charge coupled device (CCD) line connected to a drift field structure. The drift field is exposed to the incoming light. It collects the generated charge and forces it to move to the pick-up point. At this pick-up point, the CCD element samples the charge for a given time and then shifts the charge packets further on in the daisy chain. After a certain amount of shifts, the multiple charge packets are stored in so-called integration gates, in a preferred embodiment. The number of integration gates gives the number of simultaneously available taps. When the cycle is repeated several times, the charge is accumulated in the integration gates and thus the signal-to-noise ratio increases. The architecture is flexible in the number of taps. A dump node can be attached to the CCD line for dumping charge with the same speed as the samples are taken. Different implementations are described herein, which allow for smaller design or faster speed. The pixel structure can be exploited for e.g. 3D time-of-flight imaging. Both heterodyne and homodyne measurements are possible. Due to the highly-efficient charge transport enabled by static drift fields in the photo-sensitive region and small-sized gates in the CCD chain, high frequency bandwidth from just a few Hertz (Hz) up to greater GHz is supported. Thus, the pixel allows for highly-accurate optical distance measurements. Another possible application of this pixel architecture is fluorescence lifetime imaging microscopy (FLIM), where short laser pulses for triggering the fluorescence have to be suppressed.

Demodulation pixel with daisy chain charge storage sites and method of operation therefor

A demodulation structure for a n-tap pixel, mainly for 3D time-of-flight (TOF) applications uses a 2-stage switch structure for demodulating a modulated electromagnetic wave. An almost arbitrary number of storage sites per pixel can be implemented enabling an almost arbitrary number of samplings captured during one exposure. It also provides the option to demodulate and integrate different phasing samples according to the different modulation frequencies within the same exposure.

Multistage demodulation pixel and method

The pixel for use in an image sensor comprises a low-doped semiconductor substrate (A). On the substrate (A), an arrangement of a plurality of floating areas, e.g., floating gates (FG-FG), is provided. Neighboring floating gates are electrically isolated from each other yet capacitively coupled to each other. By applying a voltage (V&#x2212;V) to two contact areas (FGFG), a lateral steplike electric field is generated. Photogenerated charge carriers move along the electric-field lines to the point of highest potential energy, where a floating diffusion (D) accumulate the photocharges. The charges accumulated in the various pixels are sequentially read out with a suitable circuit known from image-sensor literature, such as a source follower or a charge amplifier with row and column select mechanisms. The pixel of offers at the same time a large sensing area, a high photocharge-detection sensitivity and a high response speed, without any static current consumption.

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Winterthur, Switzerland

Michael Lehmann