Wide-Area Illumination Panels With Flexible Side-Emitting LEDs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing planar waveguides face challenges in light input and distribution due to inaccessible edges or impractical edge-lit applications, particularly in transparent slabs like glass or plastic panels with roughened edges or tapered shapes, and light input apertures that are too small for large light sources.
Innovation Solution
A face-lit planar waveguide illumination system that injects light into the face of a planar waveguide using an elongated optical element, such as a linear prism or film, coupled with a light source to propagate light via total internal reflection (TIR) and extract it at another location, eliminating the need for edge access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If light is input through the edge of a planar waveguide, then light distribution along the broad surface is achieved, but edge accessibility is required which is not available in many applications
Solution Approach 1:
The patent inverts the conventional edge-lit approach by implementing face-lit illumination. Instead of coupling light at the waveguide edges, the system couples light at the broad face of the waveguide using optical elements positioned on the surface, thereby eliminating the need for edge accessibility while maintaining light distribution functionality
Solution Approach 2:
The patent transitions from one-dimensional edge coupling to two-dimensional face coupling. By distributing optical elements across the broad face surface rather than confining coupling to the one-dimensional edge, the system enables light input in applications where edges are inaccessible
2Stability of the object's composition
If existing structural articles like framed glass windows are used as waveguides, then aesthetic and structural integrity is maintained, but edge modification is not possible
Solution Approach 1:
The patent segments the light input function from the waveguide structure itself by introducing separate optical elements (lenses, prisms, films) that can be independently positioned and attached to the face surface, allowing the waveguide structure to remain intact while enabling light coupling
Solution Approach 2:
The patent introduces optical elements as intermediaries between the light source and the waveguide face. These intermediary components (optical lenses, prismatic films, diffuser elements) facilitate light coupling without requiring direct modification of the waveguide structure or its edges
3Reliability
If light is coupled through a small aperture at the edge, then coupling is achieved, but light spillage and inefficiency occur
Solution Approach 1:
The patent expands the light coupling interface from a small one-dimensional edge aperture to a large two-dimensional face surface. This dimensional expansion allows for larger optical element apertures that can capture and couple light more efficiently, reducing spillage while maintaining coupling effectiveness
Solution Approach 2:
The patent replaces the mechanical constraint of small edge apertures with optical design solutions. By using optical elements with optimized geometries (lenses, prisms, diffusers) positioned on the face, the system achieves efficient light coupling through optical rather than mechanical means, eliminating the spillage problem associated with small apertures
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 efficient light input and distribution across a large area without edge penetration, reducing unwanted light spillage and providing controlled light propagation and extraction for applications like window panes and signage.
Implementation Method 1
propagate light via total internal reflection (TIR)
Data Source
AI summary
A backlight for an LCD display has an optically transmissive sheet with first and second broad-area surfaces, four edges, a light mixing region adjacent to a first edge, and a light extraction region. The mixing region has smooth planar surfaces for guiding light via total internal reflection. Light extraction features are distributed across the extraction region with increasing density toward the opposing edge. A flexible LED strip extends parallel to the first edge, with a flexible circuit and side-emitting LED packages of less than 2 mm in height. The LED packages have light emitting surfaces perpendicular to the circuit's major surface. A metallic housing partially encases the LED array with a linear channel providing light passage to the mixing region. At least one extraction feature has a surface relief microstructure separated from other features and edges by smooth planar portions of the sheet.