Variable Clearance Light Guide for Uniform Illumination
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Solution Overview
Problem
Existing light guiding devices for illumination systems, such as those used in motor vehicle indicators, suffer from inhomogeneous light distribution over larger surfaces and greater distances, leading to non-uniform illumination that can be misinterpreted by users.
Innovation Solution
A light guiding device with a reflection side featuring a reflection layer, arranged to decrease clearance between the reflection side and the light outcoupling side as distance from the light incoupling side increases, ensuring more uniform light distribution. The reflection layer, made of materials like ABS or PMMA, can be step-like or wave-like to deflect light uniformly, and is applied using techniques like pad printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a light guiding device is used to illuminate larger surfaces at greater distances, then the illumination area is increased, but the light distribution becomes inhomogeneous
Solution Approach 1:
The patent applies local quality by creating a distance-dependent clearance between the reflection side and light outcoupling side. The clearance varies locally across the light guiding device, being smaller near the light incoupling side and larger near the light outcoupling side. This local variation in structure compensates for the natural light intensity decay, ensuring uniform light distribution across the entire illumination area.
Solution Approach 2:
The patent changes the geometric parameter of the clearance distance between the reflection side and light outcoupling side. By making this clearance distance variable rather than constant, the light path length and outcoupling efficiency are adjusted locally to compensate for distance effects, maintaining uniform illumination intensity across the entire illuminated surface.
2Device complexity
If the clearance between reflection side and light outcoupling side is constant, then the device structure is simple, but light distribution becomes inhomogeneous over larger surfaces
Solution Approach 1:
The patent transitions from a constant clearance structure to a locally variable clearance structure. The clearance distance is optimized locally at different positions along the light path, with smaller clearances near the light source and larger clearances farther away, achieving uniform light distribution while maintaining reasonable structural complexity.
Solution Approach 2:
The patent introduces a gradient variation in the clearance dimension, transforming the structure from a two-dimensional constant gap to a three-dimensional variable gap profile. This dimensional change allows for continuous adjustment of light outcoupling characteristics along the propagation direction, achieving uniform illumination across the illuminated surface.
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 solution achieves a more uniform illumination over larger surfaces, reducing the visibility of inhomogeneities and ensuring accurate indicator light interpretation by drivers, even in larger blind spot monitor pictograms.
Implementation Method 1
a light guiding device (2) having a light incoupling side (4) for coupling light from a light source into the light guiding device (2), a reflection side (6) having a reflection layer (8) for reflecting the incoupled light
Data Source
AI summary
A light guiding device for an illumination device, especially for a motor vehicle or an indicator device in a rearview device of a motor vehicle includes a light coupling side for incoupling light from a light source, a reflection side having a reflection layer; and a light outcoupling side, which is disposed generally opposite the reflection side. A clearance between the reflection side and the light outcoupling side generally decreases as the distance from the light incoupling side increases. The reflection side having the reflection layer is configured so that light arriving from the light incoupling side is deflected to the light outcoupling side. The reflection layer may be a paint or lacquer layer that is imprinted or evaporation-coated on the reflection side; and the having a white sheet on or next to the rejection side.