Multi-focal AR Display Using Composite Variable Focus Elements

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Solution Overview

Problem

Current augmented reality systems face challenges in delivering high-speed, high-quality 3D virtual content with accurate depth perception, eye relief, and portability, as they struggle to simultaneously present multiple depth planes effectively.

Innovation Solution

A composite variable focus element system comprising two VFEs, one with a large focus range and the other capable of rapid switching between focal states, is used in conjunction with an accommodation tracking module and a high refresh rate light projection display to dynamically adjust and present multiple depth planes based on user eye accommodation, creating a seamless 3D experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a single variable focus element (VFE) is used, then the system structure is simple, but the focus modulation speed and range are limited

Engineering Contradiction:
Improvefocus modulation speedVSAvoidsystem structure
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent divides the focus modulation function into multiple independent VFEs (first VFE and second VFE), each responsible for different focal ranges. This segmentation allows parallel operation of multiple VFEs, achieving faster overall focus modulation speed while maintaining reasonable individual component complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple VFEs with different focal ranges into a unified optical system where their effects are integrated. The first VFE handles near-focal adjustments while the second VFE handles far-focal adjustments, and their combined operation achieves both high speed and extended focus range without proportionally increasing system complexity

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If multiple variable focus elements (VFEs) are used to achieve large focus range, then the focus modulation capability is improved, but the system size and power consumption increase

Engineering Contradiction:
Improvefocus rangeVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic focus modulation by independently controlling multiple VFEs based on the required focal distance. Each VFE is activated only when needed for its specific focal range, enabling adaptive power consumption that matches the actual operational requirements rather than continuously powering all components

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By segmenting the focus range into multiple zones handled by different VFEs, the system only activates the specific VFE needed for the current viewing distance. This reduces overall power consumption compared to using a single VFE that must continuously operate across the entire focus range

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If multiple variable focus elements (VFEs) are used to achieve multi-focal imagery, then the depth perception quality is improved, but the device complexity increases

Engineering Contradiction:
Improvedepth perception accuracyVSAvoidoptical system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent assigns different focal range specializations to different VFEs, creating local optimization where each component excels at its designated function. The first VFE is optimized for near-focal precision while the second VFE is optimized for far-focal precision, achieving high overall depth perception accuracy without requiring every component to be equally complex

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the depth perception function across multiple VFEs, each handling specific depth zones. This segmentation allows the system to achieve high precision depth perception across the entire range by combining the specialized capabilities of individual VFEs, rather than requiring a single overly complex component

Inventive Principle:
Principle #1Segmentation

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 enables the simultaneous perception of multiple depth planes, enhancing the user's 3D experience by ensuring rapid and accurate focus adjustments, improving the system's speed, quality, and portability, while maintaining stable image magnification.

Implementation Method 1

modulate the focus of a display image in response to a change in a viewer's accommodation or fixation distance

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP4099274A1Multi-focal display system and method
Publication Date: 2022.12.07 MAGIC LEAP INC
  • EP4099274A1 patent drawingFigure 1
  • EP4099274A1 patent drawingFigure 2
  • EP4099274A1 patent drawingFigure 3

AI summary

Configurations are disclosed for presenting virtual reality and augmented reality experiences to users. An augmented reality system provides one or more frames of image data to be presented to a user through two variable focus elements arranged in series.