Curved Light Guide Image Combiner With Parallel-Ray Reflection
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Solution Overview
Problem
Conventional curved light guide image combiners in near-eye displays suffer from image formation errors due to non-parallel propagation of output rays, leading to blurry or low-contrast images.
Innovation Solution
A curved light guide image combiner system with reflective layers configured to transform non-parallel input rays into parallel output rays, using an input coupler, output coupler, and reflective layers to maintain consistent propagation directions through total internal reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional curved light guide image combiners are used, then the device structure is simple, but image formation errors occur due to non-parallel propagation of output rays resulting in blurry or low-contrast images
Solution Approach 1:
The optical system is segmented into distinct functional components: in-coupling element, out-coupling element, and reflective layer. Each element performs a specific function in transforming ray propagation, allowing the complex task of achieving parallel output rays to be divided into manageable stages that can be optimized independently.
Solution Approach 2:
The reflective layer acts as an intermediary element between the in-coupling and out-coupling elements. It receives non-parallel rays from the in-coupling element, transforms them into parallel rays through reflection, and directs them to the out-coupling element, thereby mediating the ray propagation to achieve the desired parallel output.
2Manufacturing precision
If reflective layers are added to transform non-parallel rays into parallel rays, then image clarity and contrast are enhanced, but the device complexity increases
Solution Approach 1:
The light guide features a curved surface geometry that works in conjunction with the reflective layer to control ray propagation. The curvature is specifically designed to transform the path of non-parallel rays into parallel output rays when combined with the reflective transformation, leveraging geometric optics principles.
Solution Approach 2:
The reflective layer changes the propagation direction parameter of the rays from non-parallel to parallel. By altering this critical parameter through controlled reflection, the system achieves improved image formation without requiring complete redesign of the entire optical path.
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
Enhances image clarity and contrast by ensuring parallel propagation of output rays, improving the overall image quality in near-eye displays.
Implementation Method 1
The reflective layer is configured to reflect the plurality of second rays as a plurality of third rays propagating in parallel directions toward the out-coupling element and the light guide
Implementation Method 2
using an input coupler, output coupler, and reflective layers to maintain consistent propagation directions through total internal reflection
Data Source
AI summary
A device is provided. The device includes a light guide having a curved surface. The device also includes an out-coupling element coupled with the light guide at an output portion of the light guide. The device further includes a reflective layer disposed at the output portion of the light guide. The out-coupling element is configured to couple a first ray propagating inside the light guide out of the light guide as a plurality of second rays propagating in non-parallel directions toward the reflective layer. The reflective layer is configured to reflect the plurality of second rays as a plurality of third rays propagating in parallel directions toward the out-coupling element and the light guide.