VCSEL 3D Sensing System Thermal Management via Segmentation

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Solution Overview

Problem

Current miniaturization efforts for optical 3-dimensional sensing systems, such as those for smartphones, face challenges in integrating compact and efficient solutions for distance measurement and image generation.

Innovation Solution

The proposed optical 3-dimensional sensing system employs a vertical-cavity surface emitting laser (VCSEL) emitter with a driver to modulate electromagnetic radiation, a single-photon avalanche diode receiver, and a processing unit to determine the time of flight and angular distribution of the radiation, enabling the creation of two- and three-dimensional images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a VCSEL array and image sensor are mounted on the same surface of a heat sink, then the system achieves compact integration, but the system generates excessive heat that degrades sensor performance

Engineering Contradiction:
Improvesystem sizeVSAvoidheat generation
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The patent divides the VCSEL array into multiple independently controllable groups that can be activated sequentially rather than simultaneously. This temporal segmentation allows the system to maintain compact physical integration while reducing peak heat generation at any given moment, thereby preventing thermal degradation of sensor performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic activation of VCSEL groups with duty cycles significantly less than 100%. By operating in pulsed intervals with sufficient cooling periods between pulses, the system achieves compact integration while maintaining average power levels that prevent excessive heat accumulation and sensor degradation.

Inventive Principle:
Principle #19Periodic action

2Reliability

If the VCSEL array operates with high duty cycle, then the system achieves sufficient signal strength for accurate measurement, but the heat generation degrades sensor performance

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidheat generation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent segments the VCSEL array into multiple groups that can be activated in sequence. This allows the system to distribute the total required signal energy across multiple lower-power pulses, maintaining measurement accuracy through accumulated signal strength while preventing any single pulse from generating excessive heat that would degrade sensor performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses periodic pulsed operation with optimized duty cycles to achieve sufficient average signal strength for accurate time-of-flight measurements while allowing the system to cool between pulses. This periodic action resolves the contradiction by maintaining reliability through signal accumulation over time while limiting peak power to prevent thermal degradation.

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If the emitted radiation is spread over a large solid angle, then the system achieves sufficient light coverage for 3D sensing, but the system size increases

Engineering Contradiction:
Improveangular coverageVSAvoidsystem size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent implements dynamic control of VCSEL groups to electronically steer and scan the emission beam across different angular directions. Instead of using fixed wide-angle emitters that would require large physical size, the system dynamically activates different VCSEL groups in sequence to sweep coverage across the required solid angle, achieving versatile angular coverage with a compact physical footprint.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration allows for a miniaturized system capable of generating accurate 3D images with varied angular distribution, enhancing the capabilities of consumer products like smartphones by integrating a compact and efficient 3D scanner.

Implementation Method 1

the emitter is a vertical-cavity surface emitting laser. The driver is configured to generate a driving current for the emitter

Methodology Applied
Scientific EffectLight emission from VCSEL: Laser

Implementation Method 2

a driver connected to the emitter, the driver providing a modulation of the electromagnetic radiation

Methodology Applied
Scientific EffectModulation of electromagnetic radiation: Phase Modulation

Implementation Method 3

a single-photon avalanche diode receiver

Methodology Applied
Scientific EffectPhoton detection: Photoelectric Effect

Implementation Method 4

single-photon avalanche diode receiver

Methodology Applied
Scientific EffectAvalanche breakdown: Avalanche Breakdown

Implementation Method 5

a processing unit configured to obtain data from a time of flight of a signal emitted by the emitter and detected by the receiver as a reflected signal after reflection by an object

Methodology Applied
Scientific EffectTime of flight measurement: Time of Flight

Implementation Method 6

obtain data from a time of flight of a signal emitted by the emitter and detected by the receiver as a reflected signal after reflection by an object

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3226024B1Optical 3-dimensional sensing system and method of operation
Publication Date: 2021.08.25 AUSTRIAMICROSYSTEMS AG
  • EP3226024B1 patent drawingFigure 1
  • EP3226024B1 patent drawingFigure 2~5

AI summary

The optical 3-dimensional sensing system comprises an emitter (1) for emitting electromagnetic radiation, a receiver (2) for detecting the radiation, a driver (3) connected to the emitter, the driver providing a modulation of the electromagnetic radiation, and a processing unit (4) configured to obtain data from a time of flight of a signal (5) emitted by the emitter and detected by the receiver as a reflected signal (5*) after reflection by an object (6). The processing unit (4) is further configured to determine a two-dimensional image of the object from the data that are obtained from the time of flight.