Retroreflective Mirror Array Layout for Compact Optical Elements
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Solution Overview
Problem
Existing optical elements, such as light guides, face challenges in miniaturization and enhancing optical performance.
Innovation Solution
The optical element incorporates a mirror array with specific arrangements of retroreflective mirrors, including first and second mirror groups that are juxtaposed and partially overlapping in various directions, and transparent mirrors with varying reflectance properties to optimize optical performance and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light guide is designed with retroreflective portions to reverse light direction, then optical performance is improved, but the device size increases and miniaturization becomes difficult
Solution Approach 1:
The patent implements nesting by placing the mirror array inside the light guide member, with retroreflective mirrors arranged in multiple groups that are juxtaposed and partially overlapping. This nested configuration allows the optical elements to occupy the same spatial volume, enabling miniaturization while maintaining high optical performance through multiple reflections within the compact structure.
Solution Approach 2:
The patent applies dimensionality change by arranging retroreflective mirrors in multiple groups (first mirror group and second mirror group) that are juxtaposed in directions intersecting the extension direction of individual mirrors. The mirrors extend obliquely to the optical surface in directions that intersect and are oblique to the optical surface, creating a three-dimensional configuration that compactly packs optical paths while maintaining performance.
2Reliability
If multiple retroreflective mirrors are arranged to enhance optical performance, then reflectivity is improved, but stray light increases and optical precision deteriorates
Solution Approach 1:
The patent applies local quality by making the first and second mirror groups have different extend directions oblique to the optical surface. The first mirror group extends in a first oblique direction while the second mirror group extends in a second oblique direction that is different from the first. This differentiation creates localized optical paths that reduce stray light by directing reflections along specific trajectories, while each group maintains high reflectivity through its retroreflective mirrors.
3Reliability
If transparent mirrors with varying reflectance are used to optimize optical paths, then optical performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by configuring transparent mirrors with different reflectance values in different regions. The first transparent mirror has a first reflectance value while the second transparent mirror has a second reflectance value, creating a gradient of optical properties. This allows optimization of optical paths by controlling light transmission and reflection at different stages, while the mirrors can be manufactured using standard coating techniques applied to substrates in the appropriate positions.
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 enables a compact optical element with high optical performance, minimizing stray light and enhancing reflectivity and transparency, suitable for display and imaging applications.
Implementation Method 1
a retroreflective portion for reversing the traveling direction of the image light guided inside a light guide member of the light guide
Implementation Method 2
the first transparent mirror has a reflectance lower than that of the second portion of the first transparent mirror or that the first portion of the second transparent mirror has a reflectance lower than that of the second portion of the second transparent mirror
Data Source
AI summary
An optical element includes a mirror array and an optical surface opposed to the mirror array. The mirror array includes a mirror group including a plurality of retroreflective mirrors arranged in an X direction, and a mirror group including a plurality of retroreflective mirrors arranged in the X direction. The mirror group and the mirror group are juxtaposed in a Y direction. The plurality of retroreflective mirrors of the mirror group extends along a W1 direction oblique to the optical surface. The plurality of retroreflective mirror of the mirror group extends along a W2 direction oblique to the optical surface. The mirror group and the mirror group overlap in part in a V1 direction.