3D Optical Incoupling Element for Uniform Planar Lightguide Illumination
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Solution Overview
Problem
Existing optical waveguide solutions face challenges with non-uniform light distribution, insufficient coupling, and light trapping, particularly in large-sized window illumination, due to the lack of integrated air-cavity optics-based solutions with satisfactory versatility and adaptability.
Innovation Solution
An optical incoupling element with a three-dimensionally formed substrate and embedded optical patterns, configured to incouple light from a planar surface and adjust its direction using total internal reflections, featuring optically functional cavities filled with materials of varying refractive indices to achieve efficient light propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional lightguide solutions use separate optical films (BEFs) or microlens/V-groove patterns, then light distribution control is partially achieved, but fully controlled light distribution in a desired manner is impossible
Solution Approach 1:
The patent combines multiple optical functions (incoupling, light distribution control, and extraction) into a single integrated lightguide element with embedded optical patterns. The optical patterns are directly formed within the lightguide medium, eliminating the need for separate optical films and achieving full control over light distribution.
Solution Approach 2:
The lightguide element is designed to perform multiple functions simultaneously: it guides light, controls angular distribution, and enables both incoupling and extraction. The embedded optical patterns provide universal control over light propagation throughout the entire lightguide structure.
2Ease of manufacture
If light incoupling is performed at the edge of the lightguide without advance optic solution, then the structure is simple, but light incoupling efficiency and control are insufficient
Solution Approach 1:
The optical patterns are embedded within the lightguide element before light incoupling occurs. These pre-formed patterns prepare the lightguide to efficiently capture and control incident light, improving incoupling efficiency while maintaining structural integration.
3Adaptability or versatility
If planar surface incoupling is utilized with surface relief gratings in augmented/virtual reality headsets, then incoupling from planar surface is achieved, but the solution lacks versatility for large-sized window illumination
Solution Approach 1:
The patent transitions from edge-based one-dimensional incoupling to planar surface two-dimensional incoupling. The embedded optical patterns are distributed across the planar surface, enabling efficient light capture over large areas while maintaining control, thus achieving versatility for both compact and large-scale applications.
4Illumination intensity
If optical patterns are embedded in the lightguide to control light propagation, then light distribution control is improved, but manufacturing complexity increases
Solution Approach 1:
The optical patterns are integrated directly into the lightguide element during manufacturing, combining the lightguide and optical control structures into a single component. This approach achieves uniform light distribution while streamlining the manufacturing process by eliminating separate assembly steps for optical films.
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 incoupling element enables uniform light distribution and improved optical efficiency by capturing and redirecting light within the waveguide, preventing leakage, and allowing for flexible integration with light sources, making it suitable for large-sized window illumination and high-volume production.
Implementation Method 1
adjust its direction using total internal reflections, featuring optically functional cavities filled with materials of varying refractive indices to achieve efficient light propagation
Implementation Method 2
optically functional cavities filled with materials of varying refractive indices to achieve efficient light propagation
Data Source
AI summary
An optical incoupling element (100) provided in the form of a discrete item attachable on a lightguide (20) is provided, comprising a substrate (100A) and at least one three-dimensionally formed optical surface (104). The optical surface (104) is configured to incouple light incident thereto and to adjust direction of the incoupled light transmitted through an optical contact surface (107) established at an interface between the element substrate (100A) and a lightguide medium (20) such, that the incoupled light acquires a propagation path through a lightguide medium (20) via a series of total internal reflections. The optical surface (104) may comprise at least on optical cavity pattern (101). The element (100) is configured to receive light onto said at least one three-dimensionally formed optical surface (104) from a direction essentially parallel to a longitudinal plane of the planar lightguide (20). A method for manufacturing the optical incoupling element (100), related arrangement, optical unit (250) and uses are further provided.