Refractive-Index Patterned Optical Member for Light Extraction
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Solution Overview
Problem
Existing lightguides with concave-convex shapes suffer from light scattering, mechanical weakness, and complex manufacturing processes, making them difficult to laminate with other members and costly to produce.
Innovation Solution
An optical member with a first layer having a first region and second regions, where the refractive indices satisfy n1 < n3 < n2, integrated with a lightguide to selectively extract light, enhancing mechanical strength and reducing light scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If concave-convex shapes are formed on the lightguide surface to extract light, then light extraction is achieved, but the lightguide becomes difficult to make thin or laminate with other members
Solution Approach 1:
The light extraction function is segmented from the lightguide structure itself and transferred to a separate optical member with micropore layers. This allows the lightguide to maintain a simple, flat structure suitable for thinning and lamination, while the extraction function is performed by the modular optical member that can be attached to the lightguide surface.
Solution Approach 2:
An optical member serving as an intermediary component is introduced between the lightguide and the external environment. This optical member contains the micropore structures needed for light extraction, allowing the lightguide itself to remain structurally simple and easily laminatable while still achieving the desired light extraction through the intermediary layer.
2Illumination intensity
If concave-convex shapes are formed on the lightguide surface, then light extraction is achieved, but production becomes time-consuming and costly
Solution Approach 1:
The manufacturing process is segmented by separating the lightguide fabrication from the light extraction structure fabrication. The optical member with micropore layers can be produced independently using techniques like phase separation or foam formation, which are more cost-effective and less time-consuming than forming precise concave-convex shapes directly on the lightguide.
Solution Approach 2:
The optical member with micropore structures serves as a disposable or replaceable component that can be mass-produced using inexpensive methods. Rather than investing in complex molding processes for the lightguide itself, the extraction function is achieved through a separate, easily manufacturable optical member that can be attached to standard lightguides.
3Illumination intensity
If regions of low refractive index with porous structures are used, then light extraction is enhanced, but the regions become very brittle and difficult to handle
Solution Approach 1:
The optical member is constructed as a composite structure with multiple layers including micropore layers (for light extraction) and support layers (for mechanical strength). The micropore layers provide the necessary refractive index contrast for efficient light extraction, while the support layers compensate for the brittleness and provide handling strength, creating a composite material system that combines optical performance with mechanical robustness.
4Illumination intensity
If interfaces between regions of considerably different refractive indices are created, then light extraction is achieved, but light scattering due to reflection or refraction occurs causing leakage
Solution Approach 1:
The micropores are distributed locally throughout the micropore layers rather than creating sharp interfaces between large regions of different refractive indices. This local distribution of refractive index variations extracts light gradually as it passes through the layer, reducing the occurrence of sudden reflection and refraction events that cause light scattering and leakage.
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 optical member achieves efficient light extraction with reduced scattering and improved mechanical strength, enabling easy integration with lightguides without concave-convex shapes.
Implementation Method 1
a first layer that includes a first region having a refractive index n1 and second regions having a refractive index n3... n1 to n3 satisfy inequality (1) below... light be selectively extracted from the lightguide
Data Source
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AI summary
The present invention is directed to an optical member including: a first layer that includes a first region having a refractive index n1 and a second region having a refractive index n3; and a second layer disposed on a first main surface of the first layer so as to be in contact with the first region and the second region, the second layer having a refractive index n2. The first layer includes a plurality of said second regions adjoining the first region along a planar direction of the first layer; the plurality of second regions constitute a geometric pattern; and n1 to n3 satisfy the relationship n1<n3<n2. When an optical member according to the present invention is integrated with a lightguide in use, excellent light extraction function is exhibited and leakage of light due to light scattering is suppressed, while attaining good mechanical strength at the same time.