MEMS Scanner Optical System for Compact AR Tracking

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Solution Overview

Problem

Conventional Near-Eye-Display (NED) systems are hindered by the bulk and weight of dedicated tracking devices, such as cameras and LiDAR systems, which prevent them from being compact and lightweight enough for daily use.

Innovation Solution

An optical system utilizing micro electro mechanical system (MEMS) scanners that generate computer-generated images and map terrain features using a common optical path with separate spectral bandwidths for image generation and terrain mapping, eliminating the need for dedicated systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated tracking devices (cameras and LiDAR systems) are added to NED systems, then terrain mapping and object tracking capabilities are improved, but device weight and bulk increase

Engineering Contradiction:
Improveterrain mapping capabilityVSAvoiddevice weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines image generation and terrain mapping functions into a single integrated optical system. The MEMS scanner serves dual purposes: directing visible light for display generation and directing infrared light for terrain mapping and object tracking. This merging eliminates the need for separate dedicated tracking devices, thereby reducing device weight and bulk while maintaining both functionalities.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical system is designed with multi-functionality, where the same optical components (illumination engine, MEMS scanner, optical assembly) perform multiple functions. The system can operate in different modes (image generation mode, terrain mapping mode, object tracking mode) by switching between different spectral bandwidths, making the device universal and eliminating the need for multiple specialized devices.

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

2Reliability

If dedicated tracking devices (cameras and LiDAR systems) are added to NED systems, then object tracking capability is improved, but device bulk increases

Engineering Contradiction:
Improveobject tracking capabilityVSAvoiddevice bulk
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges object tracking functionality into the existing image generation optical path. The MEMS scanner and optical assembly used for displaying images are also used for emitting and receiving infrared light for object tracking. This integration reduces device bulk by eliminating separate tracking hardware while maintaining tracking capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical system achieves multi-functionality by using the same physical components for both image generation and object tracking. By switching between visible and infrared spectral bandwidths, the system performs different functions with the same hardware, reducing the overall device volume.

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

3Reliability

If separate optical paths are used for image generation and terrain mapping, then functional performance is improved, but device complexity increases

Engineering Contradiction:
Improvefunctional performanceVSAvoidoptical system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the optical spectrum into different spectral bandwidths (visible light for image generation, infrared for terrain mapping) and directs them through the same physical optical path using wavelength-selective components. This segmentation in the spectral domain allows functional separation while maintaining physical integration, reducing device complexity compared to using completely separate optical paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces wavelength-selective components (such as dichroic mirrors or beam splitters) as intermediaries that separate and direct different spectral bandwidths within a single optical path. These intermediary components enable the system to maintain separate functional paths for image generation and terrain mapping while using a shared optical infrastructure, thereby reducing overall system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach results in a more compact and lightweight NED device capable of both image generation and terrain mapping, reducing weight and cost while enhancing user experience.

Implementation Method 1

the optical assembly causes the first spectral bandwidth and the second spectral bandwidth to propagate along a common optical path and then separate the first spectral bandwidth from the second spectral bandwidth

Methodology Applied
Scientific EffectSpectral separation: Dispersion (of waves)

Implementation Method 2

an optical system that deploys micro electro mechanical system (MEMS) scanner(s) for both generating CG images within a user's perspective of a real-world environment and also for mapping a terrain of the real-world environment

Methodology Applied
Scientific EffectMEMS scanning: Microelectromechanical Systems

Data Source

PatentEP3649537B1Compact optical system with MEMS scanners for image generation and object tracking
Publication Date: 2024.06.26 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3649537B1 patent drawingFigure 1
  • EP3649537B1 patent drawingFigure 2A~2B
  • EP3649537B1 patent drawingFigure 3~4

AI summary

An optical system that deploys micro electro mechanical system (MEMS) scanners to contemporaneously generate CG images and to scan a terrain of a real-world environment (112). An illumination engine (502) emits a first spectral bandwidth and a second spectral bandwidth into an optical assembly (500) along a common optical path (1). The optical assembly then separates the spectral bandwidth by directing the first spectral bandwidth onto an image-generation optical path (2) and the second spectral bandwidth onto a terrain-mapping optical path (7). The optical system deploys the MEMS scanners (214, 218) to generate CG images by directing the first spectral bandwidth within the image-generation optical path and also to irradiate a terrain by directing the second spectral bandwidth within the terrain-mapping optical path. Accordingly, the disclosed system provides substantial reductions in both weight and cost for systems such as, for example, augmented reality and virtual reality systems.