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BR-112018076493-B1 - SYSTEMS AND METHODS FOR DETECTING THE POSITION OF A LIGHT BEAM

BR112018076493B1BR 112018076493 B1BR112018076493 B1BR 112018076493B1BR-112018076493-B1

Abstract

This section describes techniques for determining the position of a light beam in a beamforming device. A feature can be formed in the beamforming device to affect at least a portion of a light beam when the feature is illuminated by the light beam. When the light beam is directed toward the feature in the beamforming device, a feature detection signal can be generated by a detector in response to the detection of at least the portion of the light beam affected by the feature that was illuminated by the light beam. The position of the light beam in the beamforming device at a given instant can then be determined based, at least in part, on the feature detection signal.

Inventors

  • Linda Irish
  • Russell Gruhlke
  • Manav RAINA

Assignees

  • QUALCOMM INCORPORATED

Dates

Publication Date
20260317
Application Date
20170523
Priority Date
20160624

Claims (15)

  1. 1. System (500), characterized in that it comprises: a beam shaping device (540; 589; 590) comprising a feature (544; 596, 598) configured to affect at least a portion of a light beam under illumination by the light beam; wherein the beam shaping device (540; 589; 590) comprises a lens (542; 592; 610; 620; 630); wherein the feature (542; 596, 598) comprises at least one of a line, notch or particle formed on a lens surface (542; 592; 610; 620; 630) or within the lens (542; 592; 610; 620; 630); a beam-directing device (520, 530, 532) configured to direct the light beam to the beam-shaping device (540; 589; 590) at different positions, wherein the different positions comprise a location of the feature (542; 596, 598); an optical detector (550) configured to generate a feature detection signal (552) in response to the detection of at least the portion of the light beam affected by the feature (542; 596, 598) that was illuminated by the light beam; a processor (570) configured to determine a position of the light beam in the beam shaping device (540; 589; 590) at a time based, at least in part, on the feature detection signal (552).
  2. 2. System (500), according to claim 1, characterized in that the light beam comprises a laser beam; and wherein the beam shaping device (540; 589; 590) is configured to illuminate a point on a target with the laser beam.
  3. 3. System (500), according to claim 1, characterized in that the beam shaping device (540; 589; 590) comprises a plurality of lenses (542; 592; 610; 620; 630); and in that the feature (544; 596, 598) comprises a reflective coating in an area at a boundary of two lenses in the plurality of lenses.
  4. 4. System (500), according to claim 3, characterized in that the plurality of lenses (542; 592; 610; 620; 630) is arranged in one of a one-dimensional array, a two-dimensional array and a three-dimensional array.
  5. 5. System (500), according to claim 1, characterized in that the feature (544; 596, 598) is configured to affect at least the portion of the light beam under illumination by the light beam by causing at least one of: i) a detectable change in the reflection of at least the portion of the light beam, ii) a detectable change in the transmission of at least the portion of the light beam, iii) a detectable change in the absorption of at least the portion of the light beam, or iv) a detectable combination thereof.
  6. 6. System (500), according to claim 1, characterized in that the beam guiding device (520, 530, 532) comprises an optical fiber (530, 532) configured to guide the light beam and vibrate under stimulation, such that the light beam is directed to the beam shaping device at different positions when the optical fiber vibrates.
  7. 7. System (500), according to claim 6, characterized in that the optical fiber (530, 532) comprises a cantilevered portion (532) having a floating end.
  8. 8. System (500), according to claim 6, characterized in that the beam guiding device (520, 530, 532) comprises an actuator (520) configured to stimulate the optical fiber such that the vibration of the optical fiber (530, 532) results in a predetermined scanning pattern of the light beam.
  9. 9. System (500), according to claim 8, characterized in that the actuator (520) comprises one of a piezoelectric tube, a microelectromechanical system actuator, MEMS, an electromagnetic actuator and an acoustic actuator.
  10. 10. System (500), according to claim 1, characterized in that it further comprises: a pulsed fiber laser (510) configured to generate the light beam.
  11. 11. Method (700) for use in detecting the position of a light beam, characterized in that it comprises: controlling (710) a beam-directing device to direct the light beam to a beam-shaping device at different positions, wherein the beam-shaping device comprises a feature configured to affect at least a portion of the light beam under illumination by the light beam; wherein the beam-shaping device comprises a lens; wherein the feature comprises at least one of a line, a notch, or a particle formed on or within a lens surface; and wherein the different positions comprise a location of the feature; generating (720) a detection signal in response to the detection of at least the portion of the light beam affected by the feature that was illuminated by the light beam; and determining (730) the position of the light beam in the beam-shaping device at a time based, at least in part, on the detection signal.
  12. 12. Method (700), according to claim 11, characterized in that the light beam comprises a laser beam; and wherein the beam shaping device is configured to illuminate a point on a target with the laser beam.
  13. 13. Method (700), according to claim 11, characterized in that the feature is configured to affect at least the portion of the light beam under illumination by the light beam by causing at least one of: i) a detectable change in the reflection of at least the portion of the light beam, ii) a detectable change in the transmission of at least the portion of the light beam, iii) a detectable change in the absorption of at least the portion of the light beam, or iv) a detectable combination thereof.
  14. 14. Method (700), according to claim 11, characterized in that the beam shaping device comprises a plurality of lenses; and in that the feature comprises a reflective coating in an area at a boundary of two lenses in the plurality of lenses.
  15. 15. Memory characterized in that it comprises instructions stored therein, the instructions causing the device as defined in any one of claims 2 to 10, when executed by a processor, to cause the processor to perform method (700) as defined in any one of claims 12 to 14.

Description

FUNDAMENTALS [001] Beams of light can be used to measure distances between objects. For example, a light detection and ranging (LIDAR) system is an active remote sensing system that can use beams of light to obtain the range, that is, the distance, from a source to one or more points on a target. A LIDAR system uses a beam of light (usually a laser beam) to illuminate at least a portion of the target and measures the time it takes for the beam of light emitted from the source to reach the target and then return to a detector near the source or at a known location. In other words, the range from the source to the point on the target can be determined based on the time of flight (ToF) of the light beam from the source to the detector. To measure ranges to multiple points on a target or in a LIDAR system's field of view, the laser beam is usually scanned in one or two dimensions. In many LIDAR system implementations, it is desirable to determine the position of a LIDAR beam at the LIDAR system transmitter in order to determine the LIDAR beam's position at the target at a given time. BRIEF SUMMARY [002] The techniques described herein relate to determining the position of a light beam in a beam shaping device, such as a lens or lens array, at or near a light source, for example, a transmitter of a LIDAR system or other similar system. In various embodiments, artificial features can be made in the beam shaping device to create discontinuities or enhancements in the reflection, absorption, or transmission characteristics of the beam shaping device. The position of a light beam in the beam shaping device at a given time can be determined, at least partially, based on the discontinuities or enhancements detected in the reflected, adsorbed, or transmitted light from the beam shaping device caused by the artificial features of the beam shaping device. [003] According to an example implementation, a system may include a beam shaping device including a feature configured to affect at least a portion of a light beam under illumination by the light beam. The system may also include a beam steering device configured to direct the light beam to the beam shaping device at different positions, the different positions including a feature location. The system may additionally include an optical detector configured to generate a feature detection signal in response to the detection of at least the portion of the light beam affected by the feature that was illuminated by the light beam; and a processor configured to determine a position of the light beam on the beam shaping device at a given time based, at least in part, on the feature detection signal. In some embodiments, the feature is configured to affect at least the portion of the light beam under illumination by the light beam, causing at least one of a detectable change in the reflection of at least that portion of the light beam, a detectable change in the transmission of at least that portion of the light beam, a detectable change in the absorption of at least that portion of the light beam, or a detectable combination thereof. [004] In various embodiments of the system, the light beam may include a laser beam, and the beam shaping device may be configured to illuminate a point on a target with the laser beam. In some embodiments, the system may additionally include a pulsed fiber laser configured to generate the light beam. In some systems, the beam shaping device may include a lens, and the feature may include at least one of a line, a notch, or a particle formed on or within a lens surface. In some systems, the beam shaping device may include a plurality of lenses, and the feature may include a reflective coating on an area at a two-lens boundary in the plurality of lenses. The plurality of lenses may be arranged in one of a one-dimensional array, a two-dimensional array, and a three-dimensional array. [005] In some systems, the beam steering device may include an optical fiber configured to guide the light beam and vibrate under stimulation, so that the light beam is directed to the beam shaping device at different positions when the optical fiber vibrates. In some systems, the optical fiber may include a cantilever portion with a floating end. In some systems, the beam steering device may include an actuator configured to stimulate the optical fiber so that the vibration of the optical fiber can result in a predetermined scanning pattern of the light beam, such as a spiral pattern. The actuator may include a piezoelectric tube, a microelectromechanical system (MEMS) actuator, an electromagnetic actuator, and an acoustic actuator. [006] According to an exemplary implementation, a method is described for use in detecting the position of a light beam. The method may include the control, by a controller, of a beam-directing device to direct the light beam to a beam-shaping device at different positions, where the beam-shaping device may include a feature configured to