Illuminated Signage Lightguide Layer Uniformity
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Solution Overview
Problem
Existing illuminated signage and badges using light emitting diodes (LEDs) often suffer from non-uniform brightness, either due to visual hot spots in back-lighting arrangements or gradual fading of light intensity in perimeter lighting.
Innovation Solution
The solution involves a sign or badge design that includes a printed circuit board with LEDs, a reflective layer, an optically transmissive lightguide layer, and a patterned light mask. The lightguide layer features an inverted conical recess to internally reflect light laterally, while the patterned light mask ensures uniform illumination by strategically placing opaque and transparent regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LEDs are placed behind light transmissive portions of a light mask (back-lighting arrangement), then the signage is illuminated, but visual hot spots are created with areas of high light intensity surrounded by lower light intensity areas
Solution Approach 1:
The patent applies local quality by varying the properties of different regions of the lightguide layer. Specifically, the lightguide layer includes regions with different refractive indices or optical properties - some regions are more optically dense to redirect light laterally, while other regions allow light to pass through to illuminate the mask. This local variation in optical properties eliminates hot spots by distributing light more uniformly across the signage surface.
Solution Approach 2:
The lightguide layer serves as an intermediary between the LEDs and the light mask. Instead of placing LEDs directly behind the mask (which causes hot spots), the lightguide layer mediates the light distribution by redirecting light laterally through its optically dense regions and allowing controlled light transmission through its other regions, thereby uniforming the illumination before it reaches the mask.
2Stability of the object's composition
If LEDs are placed at edges along the perimeter of the sign (perimeter lighting arrangement), then a more gradual illumination is achieved, but there is still perceptible and aesthetically displeasing fading of light intensity from the edges inwardly
Solution Approach 1:
The lightguide layer is segmented into multiple regions with different optical properties. Some segments are optically dense to redirect light laterally, while other segments allow light transmission. This segmentation enables the system to achieve uniform illumination by combining the effects of lateral redirection and controlled transmission, eliminating the fading effect seen in perimeter lighting arrangements.
3Stability of the object's composition
If a lightguide layer is used to redirect light laterally through internal reflection, then uniform illumination is achieved, but the device complexity increases with multiple layers and components
Solution Approach 1:
The patent merges multiple functions into the lightguide layer. This single layer simultaneously performs light redirection through its optically dense regions, light transmission through its other regions, and uniform distribution of illumination. By combining these functions into one integrated component rather than separate layers, the design achieves uniform illumination while minimizing device complexity.
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 design achieves high luminescence and uniform brightness across the signage or badge, eliminating hot spots and fading issues, thereby enhancing aesthetic appeal and visibility.
Implementation Method 1
light emitted from each of the plurality of light emitting diodes can be internally reflected at an optic-to-air interface of the associated inverted conical recess, and directed outwardly from the inverted conical recess and generally laterally through the lightguide layer
Implementation Method 2
one or a plurality of light emitting diodes mounted on the printed circuit board
Implementation Method 3
light emitted from each of the plurality of light emitting diodes
Implementation Method 4
a reflective layer disposed over the printed circuit board
Data Source
AI summary
An illuminated sign includes a printed circuit board a plurality of light emitting diodes mounted on the printed circuit board; a reflective layer disposed over the printed circuit board, the reflective layer being patterned to expose the light emitting diodes and a predetermined area around each of the light emitting diodes; an optionally transmissive lightguide layer disposed over the reflective layer; and a patterned light mask disposed over the clear lightguide layer, the light mask having opaque portions and transparent or translucent portions, wherein transparent or translucent portions of the light mask overlay the reflective layer and opaque portions of the light mask overlay the light emitting diodes.