Compact Illumination Module for Depth Sensing in Wearables

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Solution Overview

Problem

Conventional depth sensing light sources are bulky and costly, making them unsuitable for wearable or mobile applications, and their manufacturing processes are not compatible with automated assembly methods used in electronic component production.

Innovation Solution

A compact illumination module for near-to-eye display systems, comprising a semiconductor-based light source mounted on a circuit board with optical elements that condition and redirect light, allowing for automated manufacturing and integration with depth sensing cameras in devices like HMDs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional light sources are used in depth sensing systems, then sufficient light output and depth sensing performance are achieved, but the system becomes physically bulky and heavy

Engineering Contradiction:
Improvelight outputVSAvoidsystem weight
Core Design Contradiction:
Illumination intensityVSWeight of moving object

Solution Approach 1:

The patent merges the light source, optical elements (lens, reflector), and housing into a single integrated illumination module. The semiconductor light source is mounted directly on a circuit board within a compact housing, eliminating the need for separate assemblies and reducing overall system weight while maintaining sufficient light output for depth sensing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent nests optical elements within the housing structure. The lens and reflector are positioned within the housing cavity, with the light source mounted on the circuit board that forms part of the housing structure. This nested arrangement maximizes space utilization and minimizes the overall footprint and weight of the illumination system.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Illumination intensity

If conventional light sources with large optical elements are used, then adequate illumination is provided, but the manufacturing process becomes complex and costly

Engineering Contradiction:
Improveillumination adequacyVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent combines multiple manufacturing steps into a single automated process. The circuit board with the mounted light source is placed directly into the housing, and the optical elements are positioned using automated alignment fixtures. This merging of assembly steps enables automated manufacturing while maintaining proper optical alignment, significantly reducing manufacturing complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs self-aligning features in the housing and circuit board design. The circuit board incorporates mounting structures that automatically position the light source and optical elements in the correct locations during assembly. This self-service alignment mechanism eliminates the need for complex manual adjustment procedures, enabling automated manufacturing.

Inventive Principle:
Principle #25Self-service

3Reliability

If conventional light sources are used, then depth sensing functionality is achieved, but automated assembly with electronic components becomes infeasible

Engineering Contradiction:
Improvedepth sensing functionalityVSAvoidautomated assembly capability
Core Design Contradiction:
ReliabilityVSExtent of automation

Solution Approach 1:

The patent merges the illumination module design with standard electronic component assembly practices. The light source is mounted on a circuit board using conventional SMT techniques, and the entire module uses standardized mounting holes and fasteners that are compatible with automated pick-and-place machines and reflow soldering processes, enabling seamless integration with electronic component assembly lines.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the mounting parameters of the light source from mechanical assembly to solder-based assembly. By mounting the semiconductor light source directly to the circuit board using solder joints rather than mechanical fasteners, the illumination module can be assembled using automated SMT equipment, achieving the same level of automation as electronic component assembly while maintaining depth sensing functionality.

Inventive Principle:
Principle #35Parameter changes

4Volume of moving object

If miniaturization of depth sensors is pursued, then wearable and mobile applications become possible, but conventional light source manufacturing processes become prohibitive

Engineering Contradiction:
Improvesensor sizeVSAvoidmanufacturing cost
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent merges the illumination module manufacturing with standard PCB manufacturing processes. The circuit board is manufactured using conventional PCB fabrication techniques, and the light source and optical elements are mounted using automated assembly equipment. This merging enables the miniaturized sensor to be manufactured using cost-effective, high-volume processes rather than custom, low-volume manufacturing, making wearable applications economically viable.

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

Enables the creation of smaller, more cost-effective depth sensing systems suitable for wearable devices, such as VR/AR headsets, by using automated assembly processes and optimizing light distribution for efficient depth sensing.

Implementation Method 1

an edge-emitting semiconductor-based light source to emit light in accordance with a first illumination pattern

Methodology Applied
Scientific EffectLight emission from semiconductor: Light Emitting Diode

Implementation Method 2

The one or more optical surfaces can be collectively configured to receive, redirect, and/or collimate the light from the edge-emitting semiconductor-based light source

Methodology Applied
Scientific EffectLight redirection and conditioning: Refraction

Implementation Method 3

one or more optical surfaces at least partially light in a first illumination pattern

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3433656B1Illumination module
Publication Date: 2021.08.04 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3433656B1 patent drawingFigure 1
  • EP3433656B1 patent drawingFigure 2
  • EP3433656B1 patent drawingFigure 3

AI summary

An illumination module can comprise a circuit board, a semiconductor-based light source mounted to the circuit board, an encasing mounted to the circuit board, and one or more optical surfaces at least partially contained within the encasing. The semiconductor-based light source can emit light in a first illumination pattern. The one or more optical surfaces can be collectively configured to receive the light from the edge-emitting semiconductor- based light source. The one or more optical surfaces can include a single optical surface configured to receive, condition, and redirect the light from the edge-emitting semiconductor-based light source. As such, the one or more optical surfaces can be collectively configured to output the conditioned and redirected light from the illumination module in a second illumination pattern different from the first illumination pattern.