Light Guide Coupling Regions Stray Light Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical devices, particularly in wearable heads-up displays, face challenges with stray light leakage due to refractive index mismatches at coupling regions, leading to visual aberrations and distractions.
Innovation Solution
The use of a light guide with an incoupler, exit pupil expander, and outcoupler, mechanically coupled to a support component such as an eyeglass lens or frame, where coupling regions are positioned outside the regions where stray light becomes incident on the perimeter to minimize leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the light guide is mechanically coupled to the support component at coupling regions, then the structural stability is improved, but stray light leakage occurs due to refractive index mismatches at the coupling regions
Solution Approach 1:
The patent extracts the harmful coupling regions from the optical path by positioning them outside the regions where stray light becomes incident on the perimeter. This separation removes the source of refractive index mismatch-induced stray light from the critical optical zones, allowing structural coupling to occur only in non-interfering locations.
Solution Approach 2:
The patent applies different properties to different regions of the light guide: coupling regions are positioned in areas with specific geometric characteristics (outside stray light incidence zones) where refractive index effects are minimized or eliminated. This local differentiation allows mechanical coupling without compromising optical performance in critical regions.
2Object-generated harmful factors
If coupling regions are positioned to avoid stray light incidence areas, then stray light leakage is reduced, but the available area for mechanical coupling is constrained
Solution Approach 1:
The patent resolves the area constraint by utilizing the three-dimensional geometry of the light guide. Coupling regions are positioned on surfaces or edges that are spatially separated from the perimeter regions where stray light becomes incident, effectively using dimensional separation to provide adequate coupling area without interfering with optical performance.
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 reduces stray light leakage, minimizing visual aberrations and distractions by positioning coupling regions outside the stray light incidence areas, thereby enhancing image clarity in wearable displays.
Implementation Method 1
a light guide (LG) to receive a display light from a light engine, to direct a first portion of the display light out of the LG to form an outcoupled light
Implementation Method 2
The IC may be to receive a display light from a light engine, to direct a first portion of the display light into the LG to form an incoupled light propagating in the LG towards the EPE
Data Source
AI summary
An optical device includes a light guide (LG) attached to a support component. The LG receives a display light from a light engine, and directs a first portion of the display light out of the LG to form an outcoupled light. The LG also causes a second portion of the display light to become incident upon an outer perimeter of the LG at one or more LG regions of the LG to form one or more stray lights, respectively. The LG may be mechanically coupled to the support component at one or more coupling regions positioned outside of the one or more LG regions. A wearable heads-up display (WHUD) can incorporate the optical device.