Waveguide In-Coupler Alignment Using Secondary Light Concentricity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for aligning projectors with waveguides in augmented reality applications are error-prone and require complex algorithms due to insufficient contrast between projector projections and waveguide gratings, leading to uncertain alignment results.
Innovation Solution
A method involving a secondary light source is used to illuminate waveguide gratings through an optical path, allowing real-time alignment by comparing the centers of the projector's projection and secondary light source images to adjust for concentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional projector alignment processes are used, then alignment can be attempted, but the process becomes error-prone and produces uncertain results due to insufficient contrast between projector projections and waveguide gratings
Solution Approach 1:
A secondary light source is introduced as an intermediary element to illuminate the waveguide gratings. This secondary light source creates a distinct pattern that contrasts with the projector projection, enabling reliable differentiation between the two elements during alignment. The intermediary light source resolves the contrast problem by providing a reference pattern that is visually distinguishable from the projector output.
Solution Approach 2:
The patent utilizes different optical characteristics (effectively different 'colors' or optical signatures) between the projector projection and the secondary light source pattern. By creating a pattern from the secondary light source that has distinct optical properties from the projector projection, the system enables reliable visual differentiation and alignment verification without requiring complex algorithms.
2Measurement precision
If sophisticated algorithms are used to discern projector position, then alignment can be inferred, but the process becomes more complex and time-consuming with uncertain results
Solution Approach 1:
The secondary light source creates a visual copy or replica pattern that mirrors the waveguide grating structure. This copy provides a direct visual reference that can be immediately compared with the projector projection, eliminating the need for complex image processing algorithms to infer position. The copying approach enables rapid, intuitive alignment verification.
Solution Approach 2:
The system enables self-verification of alignment by creating a built-in reference pattern through the secondary light source. The reference pattern automatically provides the information needed for alignment verification without requiring external sophisticated algorithms or multiple imaging devices. The system serves its own alignment verification needs through the integrated reference pattern.
3Ease of operation
If alternating control of projector and secondary light source is used, then alignment discrepancies can be inferred, but the process remains error-prone and may not produce definitive alignment results
Solution Approach 1:
The patent merges the projector projection and secondary light source pattern into a single simultaneous imaging frame. This combination allows both elements to be captured and compared in one operation, eliminating the need for alternating control. The merged image provides definitive alignment information by directly comparing the projector projection with the reference pattern from the secondary light source in the same frame.
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
Enables accurate, real-time alignment of projectors with waveguides, reducing errors and simplifying the process by providing definitive alignment verification.
Implementation Method 1
supplying a secondary light source through an optical path of the planar waveguide to exit at the in-coupler of the planar waveguide as an exit light
Data Source
AI summary
A method for aligning the projection of a first light source with an in-coupler of a planar waveguide, the method including supplying a secondary light source through an optical path of the planar waveguide to exit at the in-coupler of the planar waveguide as an exit light, determining the concentricity of the exit light with respect to the first light source, and improving the concentricity of the exit light with respect to the first light source by adjusting the positioning of the first light source such that the exit light becomes concentric with the projection of the first light source.