Motor Vehicle Optical Guide With Diffusing Screen
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Solution Overview
Problem
Existing motor vehicle lighting and signaling devices with optical guides face challenges in maintaining uniform illumination levels and angular distribution of light, leading to decreased efficiency and non-homogeneous appearance, especially when viewed from angles off the longitudinal axis of the vehicle.
Innovation Solution
Incorporating a diffusing screen opposite the reflection face of the optical guide, which recovers and redirects light rays that would otherwise be lost, enhancing optical efficiency and achieving a more uniform illumination pattern across a wider range of angles through the use of reflecting prisms and diffusing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light guide is used to illuminate the vehicle headlight, then the illuminating surface can reach inaccessible areas and the style is improved, but the illumination level decreases as distance from the entry face increases, resulting in non-uniform illumination
Solution Approach 1:
A diffusing screen is introduced as an intermediary element between the light guide and the external environment. This screen receives light from the light guide's first face and redistributes it in multiple directions, ensuring uniform illumination across the headlight assembly while maintaining the aesthetic appearance of the light guide.
Solution Approach 2:
The patent changes the optical parameters of the system by introducing a diffusing screen with specific diffusion characteristics. This screen transforms the directional light output from the light guide into a more isotropic distribution, achieving uniform illumination levels across different viewing angles and positions.
2Illumination intensity
If the light guide is designed to illuminate mainly in the axis of the vehicle to meet photometric standards, then photometric requirements are satisfied, but the illuminated appearance becomes non-homogeneous when observed from angles away from the longitudinal axis
Solution Approach 1:
The diffusing screen acts as a mediator that decouples the photometric function from the aesthetic function. It receives the axially-directed light from the light guide and redistributes it angularly, ensuring that photometric standards are met while the light guide maintains a homogeneous illuminated appearance from all viewing angles.
Solution Approach 2:
The patent transitions from one-dimensional axial illumination to three-dimensional angular distribution by introducing the diffusing screen. This screen adds angular diversity to the light output, creating a homogeneous appearance across multiple viewing dimensions while maintaining compliance with photometric standards.
3Illumination intensity
If reflecting elements are disposed on the rear face of the guide to emit light over its entire length, then light is distributed along the guide, but light leakages occur through the rear face, reducing optical efficiency
Solution Approach 1:
The patent converts the harmful effect of light leakage through the rear face into a beneficial effect. By placing a diffusing screen in proximity to the light guide, the leaked light is captured and redirected back into useful illumination patterns, transforming energy loss into useful light output and improving overall optical efficiency.
4Illumination intensity
If the guide emits light with a narrow angular distribution to meet photometric standards, then axial illumination is optimized, but the guide appears little or not illuminated at high angles of incidence
Solution Approach 1:
The diffusing screen serves as an intermediary that transforms the narrow angular distribution from the light guide into a broad angular distribution. It receives axially-directed light and redistributes it across a wide range of viewing angles, ensuring the guide appears uniformly illuminated from any position while maintaining optimized axial illumination.
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 results in improved optical efficiency and a more homogeneous illuminated appearance from various angles, with increased light intensity and wider angular distribution, while maintaining photometric performance and simplifying assembly and positioning.
Implementation Method 1
the light rays emitted by this source propagate by total reflection in the length of the guide in the direction of its opposite end
Implementation Method 2
Some of the light rays propagating in the guide will emerge from it in the so-called front face of the guide by virtue of the presence of reflecting elements disposed on the so-called rear face of the guide
Implementation Method 3
it makes it possible in fact to recuperate the light escaping from the guide from its rear face and to return it at least partly into the guide with a high angular width, because of its diffusing character
Data Source
AI summary
A lighting and/or signaling device for a motor vehicle, comprising at least one light source emitting a light beam and at least one optical guide in which the light beam propagates, the optical guide comprising: a first face forming an exit face for the light beam, and a second face, opposite to the exit face, forming a reflection face for the light beam, such that the light guide is associated with a diffusing screen disposed opposite the reflection face of the light guide.