Embedded Light Guide Collimator for Uniform Illumination
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Solution Overview
Problem
Existing lighting arrangements with light guides face issues of bright spots on the outer surface due to light emitted from wide-angle sources like lambertian emitters, which are not effectively addressed in maintaining small dimensions in the transverse direction.
Innovation Solution
A lighting arrangement with a light source embedded within a light guide, featuring a collimator with a first reflector surface parallel to the forward direction and a second reflector surface inclined at a specific angle, ensuring that all emitted light is directed above the critical angle for total internal reflection, thus preventing bright spots on the outer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light source emitting light over a wide angular range is used, then the illumination coverage is improved, but bright spots appear on the outer surface of the light guide
Solution Approach 1:
A collimator is introduced as an intermediary component between the light source and the light guide. The collimator comprises a first reflector surface and a second reflector surface that work together to redirect light rays, ensuring they strike the light guide at angles above the critical angle for total internal reflection, thereby preventing bright spots while maintaining wide illumination coverage
Solution Approach 2:
The collimator changes the angular parameter of light rays by using reflector surfaces at specific angles. The first reflector surface is parallel to the forward direction while the second reflector surface is inclined, transforming the light distribution pattern to achieve uniform illumination without bright spots
2Object-affected harmful factors
If measures are taken to prevent bright spots by controlling light angles, then the quality of illumination is improved, but the dimensions in traverse direction increase
Solution Approach 1:
The collimator employs an asymmetric configuration where the first reflector surface is parallel to the forward direction and the second reflector surface is inclined at a specific angle. This asymmetric arrangement efficiently redirects light to prevent bright spots while minimizing the thickness of the collimator in the traverse direction
Solution Approach 2:
The collimator redirects light control from the traverse direction to the longitudinal direction by using the inclined second reflector surface. This allows light angle control to be achieved primarily along the length of the light guide rather than increasing the thickness, effectively using dimensional redistribution to solve the contradiction
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 configuration effectively prevents bright spots on the outer surface of the light guide while maintaining a small thickness, ensuring efficient light propagation and uniform illumination within the guide.
Implementation Method 1
Rays of light striking the medium boundary at an incident angle larger than a critical angle are entirely reflected
Implementation Method 2
Light propagates within a light guide, i. e. a transparent solid body, based on the principle of total internal reflection (TIR)
Implementation Method 3
The collimator comprises at least a first and a second reflector surface... the reflector surfaces of the collimator may serve to shape the light emitted from the light source to propagate within the light guide
Data Source
AI summary
A lighting arrangement and a method of coupling light into a light guide are described. A light source is embedded within a light guide. The light guide includes first and second outer surfaces arranged on opposite sides. A forward direction extends from the light source parallel to the first outer surface. A collimator is embedded within the light guide. The collimator comprises a first reflector surface facing towards the second outer surface and a second reflector surface facing towards the first outer surface. The light source is arranged to emit light between the first and second reflector surfaces. The first reflector surface is arranged at least substantially parallel to the forward direction. At least a portion of the second reflector surface is arranged under an angle to the forward direction.