See-through Eyepiece Light Guide for AR Displays
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Solution Overview
Problem
Conventional head-mounted displays (HMDs) face limitations due to high cost, size, weight, field of view, and efficiency of their optical systems, which restrict their practical and leisure applications in augmented reality and other fields.
Innovation Solution
A see-through eyepiece for HMDs is designed with a light guide component and a partially reflective layer, combined using a clear adhesive, to efficiently combine external scene light with display light, providing a clear view of the environment while overlaying computer-generated images, using optical coatings and materials with low stress to minimize distortion and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical systems are used in HMDs, then the system can display computer-generated images, but the cost, size, weight, field of view, and efficiency are limited
Solution Approach 1:
The patent combines the light guide component and partially reflective layer into an integrated optical assembly that merges real-world view transmission with computer-generated image display. This integration reduces the number of separate optical components needed, thereby reducing overall system complexity while maintaining display performance.
Solution Approach 2:
The patent employs composite optical structures including a light guide component made of transparent material with specific refractive index properties, combined with a partially reflective layer. This composite approach optimizes both light transmission for real-world viewing and reflection for CGI display, improving efficiency without proportionally increasing complexity.
2Reliability
If conventional optical systems are used in HMDs, then the system can function as a display device, but the size and weight increase
Solution Approach 1:
The patent extracts and eliminates redundant optical components from conventional HMD systems by using a streamlined light guide component with integrated partially reflective layer. This extraction of unnecessary elements reduces both the size and weight of the optical system while preserving essential display functionality.
Solution Approach 2:
The patent utilizes thin-film optical components including a light guide component made of transparent material with optimized thickness and a partially reflective layer. These thin-film structures provide the necessary optical functions with minimal added weight compared to bulk optical components.
3Reliability
If conventional optical systems are used in HMDs, then the system can display images, but optical distortion and astigmatism occur
Solution Approach 1:
The patent applies local quality optimization by designing the light guide component with spatially varying refractive index properties and the partially reflective layer with position-dependent reflectivity. This local optimization compensates for optical path variations across the field of view, reducing distortion and astigmatism while maintaining image display capability.
Solution Approach 2:
The patent employs curved optical surfaces in the light guide component and partially reflective layer to correct for optical aberrations. The curved geometries are specifically designed to compensate for distortion and astigmatism that occur in flat optical systems, improving manufacturing precision requirements.
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
The solution enables a compact, efficient, and high-definition augmented reality display with reduced optical distortion and astigmatism, allowing users to view virtual images superimposed over the real world without compromising the ambient environment's clarity, thus overcoming the limitations of conventional HMDs.
Implementation Method 1
a light guide component and a partially reflective layer, combined using a clear adhesive, to efficiently combine external scene light with display light
Implementation Method 2
a light guide component and a partially reflective layer, combined using a clear adhesive, to efficiently combine external scene light with display light
Data Source
AI summary
An eyepiece for a head wearable display includes a light guide component for guiding display light received at a peripheral location and emitting the display light at a viewing region. The light guide component includes an eye-ward facing surface having a reflection portion and a viewing portion, a folding surface oriented to reflect the display light received into the light guide component to the reflection portion of the eye-ward facing surface, and a first interface surface oriented to receive the display light reflected from the reflection portion of the eye-ward facing surface. A partially reflective layer is disposed on the first interface surface in the viewing region to reflect the display light through viewing portion of the eye-ward facing surface.