Integrated 3D Sensing Module With VCSEL-SPAD Co-Packaging

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Solution Overview

Problem

Existing 3D sensing technologies face challenges with system complexity, increased size, and reduced integration due to separate projector and detector modules, as well as sensitivity to reflections and scattering in time-of-flight methods, and high processing requirements in structured light methods.

Innovation Solution

An integrated electronic module with a VCSEL laser diode and SPAD detector within a single package, utilizing a rigid-flex circuit board and MEMS reflectors, allows for compact 3D sensing applications by optimizing component placement and reducing dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a split projection/detection scheme with separate projector and detector modules is used, then the system can be manufactured with existing opto-mechanical solutions, but the system complexity increases and the module size increases

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidsystem complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines the projector and detector into a single integrated module where the detector is positioned directly below the projector within the same package. This merging eliminates the need for separate opto-mechanical assemblies while maintaining manufacturability through standardized packaging processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The base substrate serves multiple functions: it provides mechanical support for both the projector and detector, enables electrical connections between components, and facilitates thermal management. This multi-functionality reduces the number of separate components needed, thereby reducing system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If a split projection/detection scheme with separate projector and detector modules is used, then the system can be manufactured with existing opto-mechanical solutions, but the module size increases

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidmodule size
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The detector is positioned directly beneath the projector within the same package footprint, creating a nested vertical arrangement. This allows both components to occupy the same horizontal space, significantly reducing the overall module size while maintaining separate functional zones.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a horizontal arrangement of separate modules to a vertical integration within a single package. By stacking the detector below the projector along the vertical axis, the module achieves compact dimensions suitable for portable devices while maintaining manufacturability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If time-of-flight approach is used for 3D sensing, then longer range with higher accuracy and less power consumption is achieved, but the system becomes sensitive to reflections and scattering phenomena

Engineering Contradiction:
Improvedepth measurement accuracyVSAvoidsensitivity to reflections and scattering
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a beam splitter as an intermediary optical element that directs light from the projector through the detector while enabling separate optical paths for measurement and reference. This intermediary component helps manage unwanted reflections and scattering by controlling light propagation paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional mechanical scanning systems with a static integrated optical design using beam splitters and fixed optical paths. This substitution reduces sensitivity to mechanical misalignments and vibrations that could exacerbate reflection and scattering issues while maintaining measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Object-affected harmful factors

If structured light approach is used for 3D sensing, then sensitivity to reflection and scattering is reduced, but heavy processing and complex component assembly are required

Engineering Contradiction:
Improvesensitivity to reflections and scatteringVSAvoidcomponent assembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the projector and detector into a single integrated module with shared mechanical support and electrical connections. This consolidation simplifies component assembly by reducing the number of separate assemblies that need to be aligned and integrated, while maintaining the structured light approach's resistance to reflections and scattering.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enhances integration and reduces costs and dimensions, enabling more efficient 3D sensing in portable devices with improved accuracy and reduced sensitivity to reflections, while maintaining high resolution and processing efficiency.

Implementation Method 1

An integrated electronic module with a VCSEL laser diode and SPAD detector within a single package

Methodology Applied
Scientific EffectLight emission from VCSEL: Laser

Implementation Method 2

Depth is calculated by measuring the time (direct ToF) or the phase shift (indirect ToF) between the emitted and the reflected beam

Methodology Applied
Scientific EffectTime-of-flight measurement: Time of Flight

Implementation Method 3

the projector typically includes a LASER source and a micro-mirror manufactured in MEMS technology; the LASER source is oriented so that a beam is directed towards the micro-mirror, and the micro-mirror is controlled in oscillation to direct the beam towards a target

Methodology Applied
Scientific EffectMEMS micro-mirror oscillation: Microelectromechanical Systems

Data Source

PatentEP3712660B1Integrated electronic module for 3D sensing applications, and 3D scanning device including the integrated electronic module
Publication Date: 2024.09.25 STMICROELECTRONICS SRL
  • EP3712660B1 patent drawingFigure 1~2
  • EP3712660B1 patent drawingFigure 3~4
  • EP3712660B1 patent drawingFigure 5A~5B

AI summary

An electronic module (2; 40; 50; 60), comprising: a substrate (2a); a covering structure (2b), coupled to the substrate to form a chamber (4). The chamber houses: an emitter (12) adapted to emit a radiation (18); a resonant reflector (10); a detector (22); and a fixed reflector (16). First and second windows (20, 26) extend through the covering structure (2b). The emitter (12), the first reflector (10) and the second reflector (16) are reciprocally arranged such that the emitted radiation generated by the emitter is received by the fixed reflector (16), is reflected towards the MEMS reflector (10), and then is reflected towards the first window, to form an output of the electronic module. The detector (22) and the second window (26) are reciprocally arranged such that an incoming radiation (24) passing through the second window (26) is received by the detector. The electronic module can be used for 3D sensing application.