Light Guide Collimating Entry Face for Homogeneous Illumination
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Solution Overview
Problem
Conventional light guides struggle to illuminate lateral exit faces homogeneously over long lengths, leading to light loss due to inappropriate collimation and reflection patterns.
Innovation Solution
A light guide with a profiled entry face that collimates light in a transverse direction, featuring a constant two-dimensional planar profile portion, allowing direct deflection of light rays to the exit face without reflection on other guide faces, reducing absorption losses and optimizing optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional collimator is used at the input face to collimate light in the longitudinal direction, then light propagation along the main direction is improved, but the light fails to encounter the decoupling face and the output face is not illuminated
Solution Approach 1:
The patent changes the collimation direction from longitudinal to transverse by profiling the input face with a constant profile portion that extends in the transverse direction. This creates a three-dimensional surface that collimates light in the transverse plane while maintaining longitudinal propagation, allowing light to reach both the decoupling face and output face effectively.
2Illumination intensity
If total reflection zones are configured to reflect light at large angles to promote homogeneity close to the input face, then light homogeneity is improved near the input face, but the light guide cannot illuminate the output face homogeneously over long lengths
Solution Approach 1:
The patent introduces a constant profile portion at the input face that provides localized collimation in the transverse direction. This local modification creates a specific optical zone that directs light toward the output face without requiring large-angle reflections, enabling homogeneous illumination over extended lengths while maintaining effectiveness near the input face.
3Illumination intensity
If light is reflected multiple times on the guide face to ensure homogeneity, then light distribution is improved, but absorption losses increase due to longer light path
Solution Approach 1:
The constant profile portion at the input face performs preliminary collimation of light in the transverse direction before the light enters the guide. This preliminary action directs light along a more direct path to the output face, reducing the number of reflections and the corresponding absorption losses while maintaining homogeneous light distribution.
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 ensures homogeneous illumination of the exit face over a great length by minimizing light absorption and reflections, making it suitable for long light guides like vehicle third brake lights.
Implementation Method 1
said entry face being profiled so as to form a collimator... so as to carry out collimation in a longitudinal plane perpendicular to said transverse direction
Implementation Method 2
a guide face by total internal reflection of the light in the transparent or translucent material
Implementation Method 3
a decoupling face with facets for reflecting the light towards the exit face
Data Source
Figure 1~3
Figure 4
AI summary
The invention relates to a light guide (2) extending in a main direction (4) and comprising an inlet face (6) for the light emitted by a light source (8), the inlet face (6) being contoured to form a collimator; a face for guiding the light (10); a light outlet face (14); and a face for decoupling the light towards the outlet face (14), the decoupling face being transversely opposite to the outlet face (14); wherein at least one portion of the profile of the inlet face (6) is constant in a transverse direction (18) so as not to collimate the light in a longitudinal plane comprising the transverse direction (18) but in a longitudinal plane perpendicular to the transverse direction (18).