Optoelectronic modules operable to collect distance data via time-of-flight and triangulation

Patent metadata

Field	Value
Publication number	US-10401496-B2
Application number	US-201615240146-A
Country	US
Kind code	B2
Filing date	Aug 18, 2016
Priority date	Sep 30, 2015
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

An optoelectronic module operable to collect distance data via a time-of-flight mode and a time-of-flight-triangulation mode includes an illumination assembly and an imaging assembly. The imaging assembly includes at least one demodulation pixel operable to determine distance to an object via a time-of-flight mode and a time-of-flight-triangulation mode. Multi-path distance inaccuracies can be mitigated in some implementations.

First claim

What is claimed is:

1. An optoelectronic module operable to capture distance data using a time-of-flight mode and operable to capture distance data using a time-of-flight-triangulation mode, the optoelectronic module comprising:
an illumination assembly, an imaging assembly, and a processor;
the illumination assembly operable to generate an illumination on an object at an object distance, wherein the illumination is modulated with a modulation frequency;
the imaging assembly having an optics assembly and a demodulation pixel;
the optics assembly having an optical axes and an on-axis focal-length, wherein the optical axis is disposed at a baseline from the illumination assembly;
the demodulation pixel being separated from the optics assembly by an on-axis focal-length;
the imaging assembly being operable to collect a portion of the illumination light reflected from the object, wherein a portion of the reflected light is focused on the demodulation pixel at a location of initial charge-carrier generation, the portion of the reflected light focused on the demodulation pixel forming a plurality of charges;
the module being arranged such that a portion of the plurality of charges are conducted from the location of initial charge-carrier generation to a demodulation assembly, the distance between the location of initial charge-carrier generation and the demodulation assembly being an intra-pixel distance, wherein the portion of the plurality of charges conducted to the demodulation assembly over the intra-pixel distance produce a signal;
the signal having a phase change, wherein the processor is operable to correlate the phase change to the intra-pixel distance;
the processor being further operable to correlate the intra-pixel distance to the object distance via the time-of-flight-triangulation mode; and
the processor being further operable to correlate the phase change to the object distance via the time-of-flight mode.

2. An optoelectronic module as in claim 1 ,
the imaging assembly being operable to collect respective portions of the reflected light, wherein each of the respective portions of the reflected light is focused on the single demodulation pixel at a plurality of respective locations of initial charge-carrier generation, each respective portion of the reflected light focused on the single demodulation pixel respectively forming a plurality of charges at each respective location of initial charge-carrier generation;
the module being arranged such that a plurality of charges at each respective location of initial charge-carrier generation are conducted from the respective locations of initial charge-carrier generation to respective demodulation assemblies, the respective distances between the respective locations of initial charge-carrier generation and the respective demodulation assemblies being respective intra-pixel distances, wherein the respective portions of the plurality of charges conducted to the respective demodulation assemblies over the respective intra-pixel distances form a plurality of respective signals;
the plurality of respective signals each being characterized by a respective phase change, wherein the processor is operable to correlate each respective phase change to a respective intra-pixel distance;
the processor being further operable to correlate each of the respective intra-pixel distances to an object distance via the time-of-flight-triangulation mode; and
the processor being further operable to correlate each of the respective phase changes to an object distance via the time-of-flight mode.

3. An optoelectronic module as in claim 1 ,
the imaging assembly having a plurality of demodulation pixels; and
the plurality of demodulation pixels being separated from the optics assembly by an on-axis focal-length.

4. An optoelectronic module as in any one of claim 1 , 2 or 3 , in which the illumination assembly further comprises an illumination optical assembly, the illumination optical assembly including at least one of: a diffraction grating, a microlens array, a lens, a prism, a micro-prism array, a diffractive optical element, or other refractive optical elements.

5. An optoelectronic module as in any one of claim 1 , 2 or 3 , in which the illumination assembly is operable to generate an emission comprised of wavelengths in the infrared spectrum.

6. An optoelectronic module as in any one of claim 1 , 2 or 3 , in which the optoelectronic module is operable to reduce multipath multi-path errors relative to the time-of-flight-triangulation or time-of-flight modes alone.

7. An optoelectronic module as in any one of claim 1 , 2 or 3 , in which the processor is further operable to adjust the modulation frequency such that the phase change is optimized to determine the distance to the object via the time-of-flight mode.

8. An optoelectronic module as in any one of claim 1 , 2 or 3 , in which the processor is further operable to adjust the conduction of charge carriers to the demodulation assembly such that the phase change is optimized to determine the distance to the object via the time-of-flight-triangulation mode.

9. An optoelectronic module as in any one of claim 1 , 2 or 3 , in which the illumination comprises a discrete high-contrast feature.

10. An optoelectronic module as in any one of claim 1 , 2 or 3 , in which the illumination comprises an array of discrete high contrast features.

11. An optoelectronic module as in any one of claim 1 , 2 or 3 , in which the illumination assembly is operable to produce consecutive illuminations, wherein the illuminations are configured respectively for optimal object distance data acquisition via the time-of-flight mode or the time-of-flight-triangulation mode.

12. A method of determining distance to an object using an optoelectronic module, the method comprising:
illuminating an object at a distance from the optoelectronic module using modulated illumination;
collecting, in the module, light reflected from the object, wherein at least a portion of the reflected light is focused on a demodulation pixel in the module to produce a plurality of charges;
conducting the plurality of charges over an intra-pixel distance to a demodulation assembly in the module to produce a signal having a phase change;
determining whether collected phase-change data is within a time-of-flight-region or a time-of-flight-triangulation region;
if it is determined that the collected phase-change data is within the time-of-flight-triangulation region:
(i) correlating the phase change to the object distance via a time-of-flight-triangulation mode; and
(ii) if it is determined that distance data is not accurate, and altering a drift-field within the demodulation pixels so as to collect more accurate distance data; and

if it is determined that the collected phase-change data is within the time-of-flight region:
(i) correlating the phase change to the object distance via a time-of-flight mode; and
(ii) if it is determined that distance data is not accurate, altering a demodulation frequency so as to collect more accurate distance data.

13. The method of claim 12 including adjusting a modulation frequency of the modulated illumination such that the phase change is optimized to determine the distance to the object via the time-of-flight mode.

14. The method of claim 12 including adjusting conduction of charge carriers to the demodulation assembly such that the phase change is optimized to determine the distance to the object via the time-of-flight-triangulation mode.

15. The method of any one of claim 12 , 13 or 14 wherein the il

Assignees

• Ams Sensors Singapore Pte Ltd

Inventors

• Buettgen Bernhard

Classifications

• G01S17/48

  Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves · CPC title

• G01S17/36 Primary

  with phase comparison between the received signal and the contemporaneously transmitted signal · CPC title

• G01S7/4915

  Time delay measurement, e.g. operational details for pixel components (signal extraction and conditioning G01S7/493); Phase measurement · CPC title