Curved LCoS Substrate Eliminates Fringe Field Effects in AR/VR Microdisplays
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Solution Overview
Problem
Current optical devices for VR and AR applications face challenges due to the use of flat LCoS substrates, which result in fringe field effects (FFE) that affect image quality and require improved wearable devices with enhanced light path management.
Innovation Solution
A microdisplay with a shape exhibiting a notch in at least one dimension, incorporating a light source, an optical element, an LCoS substrate, and a spatial light modulator that adjusts the azimuth angle of the liquid crystal layer to eliminate noise and fringe field effects, utilizing a polarizer, lens array, and waveguide to improve image projection without FFE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a flat LCoS substrate is used as the optical reflection surface, then the device structure is simple, but fringe field effects occur that degrade image quality
Solution Approach 1:
The LCoS substrate is transformed from a flat planar structure to a curved spherical structure with a specific radius of curvature. This curvature modifies the light path and electric field distribution, eliminating the fringe field effects that occur at the edges of flat substrates while maintaining compact device geometry.
Solution Approach 2:
The invention changes the geometric parameter of the LCoS substrate from flat (zero curvature) to curved (non-zero radius of curvature). This parameter change fundamentally alters the optical and electrical field characteristics, resolving the fringe field problem without requiring complex additional components.
2Ease of manufacture
If a flat LCoS substrate is used, then manufacturing is easier, but image quality is degraded due to FFE
Solution Approach 1:
The LCoS substrate is transformed from a flat planar structure to a curved spherical structure with a specific radius of curvature. This curvature modifies the light path and electric field distribution, eliminating the fringe field effects that occur at the edges of flat substrates while maintaining compact device geometry.
3Device complexity
If conventional optical elements are used without azimuth angle adjustment, then the optical path is simpler, but noise and FFE cannot be eliminated
Solution Approach 1:
The LCoS substrate is transformed from a flat planar structure to a curved spherical structure with a specific radius of curvature. This curvature modifies the light path and electric field distribution, eliminating the fringe field effects that occur at the edges of flat substrates while maintaining compact device geometry.
Solution Approach 2:
The invention changes the geometric parameter of the LCoS substrate from flat (zero curvature) to curved (non-zero radius of curvature). This parameter change fundamentally alters the optical and electrical field characteristics, resolving the fringe field problem without requiring complex additional components.
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 provides improved image quality, reduces FFE, and allows for a more compact optical engine with a larger Field of View (FOV), aligning better with human eye geometry, while reducing the volume of AR/VR optical engines by 25% compared to current products.
Implementation Method 1
the spatial light modulator adjusts an azimuth angle of a liquid crystal layer to eliminate noise of the outgoing light
Implementation Method 2
the LCoS substrate reflects the light source entering the notch
Implementation Method 3
a polarizer, converting a polarized light according to the incident light source
Implementation Method 4
the lens array adjusts the light path of the incident light entering the LCoS substrate
Implementation Method 5
the outgoing light is guided by a waveguide in the eyepieces
Implementation Method 6
reflected into a user's eyes by a grating
Data Source
AI summary
The invention is directed to a microdisplay of an optical device, comprising: a light source; an optical element, disposed on the light exit side of the light source to adjust the light path of the light source; an LCoS substrate, a shape of which exhibits a notch in at least one dimension, the light source projected onto the LCoS substrate, the LCoS substrate reflects the light source entering the notch; and a spatial light modulator, after an outgoing light reflected by the LCoS substrate, the outgoing light enters the spatial light modulator; the spatial light modulator adjusts an azimuth angle of a liquid crystal layer to eliminate noise of the outgoing light; wherein, the outgoing light adjusted by the spatial light modulator is projected onto a eyepieces to display images without the fringe field effects.