MEMS Mirror Switching for AR Waveguide Depth Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current augmented reality (AR) technologies face challenges in providing a comfortable and natural-feeling presentation of virtual image elements amidst real-world imagery, often resulting in uncomfortable or ineffective depth perception due to mismatched accommodation and vergence cues.

Innovation Solution

The use of microelectromechanical systems (MEMS) mirrors for depth plane switching in wearable display systems, which reduces the size and weight of projector systems and improves ergonomics by selectively routing RGB light to appropriate depth planes, enhancing the simulation of three-dimensional imagery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If traditional projector systems are used in AR devices, then image projection capability is achieved, but device size and weight increase, reducing user comfort

Engineering Contradiction:
ImproveAR device weightVSAvoidprojector system complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent divides the projector system into separate functional modules: a light source module, a spatial light modulator module, and an optical system module. This segmentation allows each component to be optimized independently and reduces the overall system size by eliminating redundant structures, directly addressing the contradiction between weight reduction and functional capability maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a nested arrangement where the spatial light modulator is positioned within the optical path of the light source, and the waveguide display elements are integrated into the housing structure. This nesting approach maximizes space utilization, reduces the overall device footprint, and minimizes the number of external optical components needed, thereby reducing both weight and complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Measurement precision

If multiple depth planes are implemented in AR display, then depth perception is improved, but accommodation-vergence mismatch increases, reducing comfort

Engineering Contradiction:
Improvedepth perception accuracyVSAvoidaccommodation-vergence mismatch
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamically adjustable optical elements including variable focus lenses and switchable waveguide layers that can change their optical properties in real-time. This dynamic capability allows the system to adjust the focal plane to match the vergence plane for each depth layer, eliminating accommodation-vergence mismatch while maintaining precise depth perception through multiple focal planes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes optical parameters such as focal length, refractive index, and optical path length to create multiple distinct depth planes. By precisely controlling these parameters, the system generates realistic depth cues that align with natural human vision, improving depth perception accuracy while maintaining comfort through proper accommodation-vergence coupling.

Inventive Principle:
Principle #35Parameter changes

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 provides a more realistic and comfortable AR experience by aligning accommodation and vergence cues, improving depth perception and reducing the size and weight of AR devices, thus enhancing user comfort and aesthetics.

Implementation Method 1

A first MEMS mirror is configured to receive the light and redirect the light to a corresponding one of the waveguides

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3423887B1Reflective switching device for inputting different wavelengths of light into waveguides
Publication Date: 2023.07.12 MAGIC LEAP INC
  • EP3423887B1 patent drawingFigure 1
  • EP3423887B1 patent drawingFigure 2
  • EP3423887B1 patent drawingFigure 3~4

AI summary

Systems and methods are provided for selectively incoupling light having different wavelengths into one of a plurality of waveguides. The systems and methods provided for selectively incoupling light having different wavelengths into one of a plurality of waveguides comprise a switching device comprising switchable reflective elements that can be configured to redirect incoming light towards an incoupling element associated with one of a plurality of waveguides.