Wearable AR Optical Paths for Wider Fields and Fewer Ghost Images

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Solution Overview

Problem

Existing augmented reality (AR) display devices suffer from a lack of design freedom, poor optical performance, small field of view, and issues such as ghost images and interference due to complex optical structures and multiple light reflections.

Innovation Solution

The AR display device incorporates two optical path modules, each comprising a beamsplitter and a reflector, with polarizing beamsplitters and wave plate subassemblies to manage light polarization, and includes beam shaping elements to optimize light propagation, enhancing design freedom and optical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a refractive correction lens is added between the beamsplitter and the human eye for users with poor eyesight, then the device can accommodate users with poor eyesight, but the structure becomes more complicated and the weight increases

Engineering Contradiction:
Improveaccommodation for users with poor eyesightVSAvoidoptical structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates a refractive correction function into the existing beamsplitter component, allowing it to serve both as a beamsplitter and a refractive correction element. This multi-functional design enables accommodation for users with poor eyesight without adding separate correction lenses, thereby avoiding increased structural complexity and weight.

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

2Reliability

If multiple optical devices are used to form the optical system, then the optical performance can be improved, but the system becomes less compact

Engineering Contradiction:
Improveoptical performanceVSAvoidsystem compactness
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines multiple optical functions into integrated components. Specifically, the beamsplitter is designed to simultaneously perform beamsplitting and refractive correction functions, reducing the number of separate optical elements needed. This merging approach maintains optical performance while achieving a more compact system configuration.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the optical structure is too simple, then the manufacture and assembly are easier, but the design parameters are limited resulting in poor image quality and low optical performance

Engineering Contradiction:
Improvemanufacture and assembly easeVSAvoidimage quality and optical performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality optimization by designing the beamsplitter with specific regional characteristics - different portions of the beamsplitter have different optical properties to simultaneously achieve beamsplitting and refractive correction. This localized functional differentiation enables complex optical performance from a single component without requiring multiple assembled elements, thus maintaining ease of manufacture while achieving high image quality.

Inventive Principle:
Principle #3Local quality

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 configuration improves the field of view and optical efficiency, reduces ghost images, and facilitates clearer image observation by optimizing the optical system design.

Implementation Method 1

a portion of the light is reflected onto the reflector 4

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a portion of the light being transmitted through the beamsplitter 3

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

polarizing beamsplitters and wave plate subassemblies to manage light polarization

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 4

beam shaping elements to optimize light propagation

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP3754412B1Wearable ar system and ar display device
Publication Date: 2025.08.13 MATRIXED REALITY TECH CO LTD
  • EP3754412B1 patent drawingFigure 1~2
  • EP3754412B1 patent drawingFigure 3
  • EP3754412B1 patent drawingFigure 4

AI summary

The application provides an augmented reality display device which comprises: a projection source module; a first optical path module comprising a first beamsplitter and a first reflector; and a second optical path module comprising a second beamsplitter and a second reflector, wherein the first reflector and the second reflector each comprise a reflective film, wherein virtual image light emitted from the projection source module and carrying virtual image information passes through the first optical path module first, in which it is reflected at least twice and transmitted at least once by means of the first beamsplitter and the first reflector, then enters the second optical path module, in which it is transmitted at least once and reflected at least twice by means of the second beamsplitter and the second reflector, and enters a human eye eventually, and wherein scene light from real scene enters the human eye through the second optical path module. The application also provides a wearable augmented reality system comprising the augmented reality display device and a projection source module of the augmented reality display device.