Eyebox Expansion Using Diffractive Elements and Polarization Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current image display systems in virtual and augmented reality lack effective methods for expanding the eyebox, which restricts the user's field of view and user experience due to limited eyebox size, leading to image loss when the user moves their eye.
Innovation Solution
The implementation of optical systems that generate multiple spatially separated light beams and utilize diffractive elements to shift images at the exit pupil, allowing for an expanded eyebox by aligning the image with the user's pupil as they move, using techniques such as laser beam scanning and beam multiplication systems with Pancharatnam-Berry phase optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If traditional optical systems are used in VR/AR displays, then the system structure remains simple, but the eyebox size is limited causing image loss when user moves their eye
Solution Approach 1:
The patent divides a single light beam into multiple spatially separated beams using diffractive elements. The optical system segments the light path to create multiple exit pupils, effectively expanding the eyebox area without requiring a completely complex reconfiguration of the entire optical system.
Solution Approach 2:
Diffractive elements are introduced as intermediary components between the light source and the exit pupil. These elements mediate the light propagation to create multiple spatially separated beams, enabling eyebox expansion while maintaining relative system simplicity.
2Reliability
If the eyebox size is increased to prevent image loss, then the user's field of view and experience improve, but the optical system complexity increases
Solution Approach 1:
The patent creates multiple dynamic exit pupils that can be selectively activated or adjusted based on user eye position. This dynamic approach ensures reliable image presentation across a larger eyebox area while managing system complexity through selective activation rather than permanently complex architecture.
Solution Approach 2:
The diffractive elements modify the spatial parameters of light propagation to create multiple separated beams. By changing the spatial distribution parameter of the light, the system achieves improved image stability during eye movement without requiring proportional increases in overall system complexity.
3Area of stationary object
If multiple spatially separated light beams are generated using diffractive elements, then the eyebox is expanded, but the device complexity increases
Solution Approach 1:
The diffractive elements create multiple copies of the light beam in different spatial locations. Instead of requiring a completely new optical path for each exit pupil, the system generates optical copies of the original beam, expanding the effective exit pupil area while avoiding proportional increases in system complexity.
Solution Approach 2:
The patent replaces traditional mechanical beam splitting mechanisms with diffractive optical elements. This substitution uses optical diffraction phenomena rather than mechanical components to create multiple spatially separated beams, reducing mechanical complexity while achieving the desired exit pupil expansion.
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 a larger eyebox, allowing users to view images across a broader field of view without losing the image as their eye position changes, enhancing the overall user experience in virtual and augmented reality applications.
Implementation Method 1
converting a single input light beam into a plurality of output light beams having different propagation directions
Implementation Method 2
beam multiplication systems with Pancharatnam-Berry phase optical elements
Data Source
AI summary
A method includes receiving a light beam propagating along an optical path and operating a polarization rotator in a first state to produce an input right-hand circularly polarized beam or in a second state to produce an input left-hand circularly polarized beam. The method also includes converting, using a first diffractive element, the input right-hand circularly polarized beam into an intermediate left-hand circularly polarized beam or converting, using the first diffractive element, the input left-hand circularly polarized beam into an intermediate right-hand circularly polarized beam. The method also includes converting, using a second diffractive element, the intermediate left-hand circularly polarized beam into a right-hand circularly polarized output beam or converting, using the second diffractive element, the intermediate right-hand circularly polarized beam into a left-hand circularly polarized output beam.