Acute-Angle Light Guide for Vehicle Lamp Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser illumination devices for vehicles face low light utilization rates due to high total internal reflection angles in materials with high refractive indices like Al2O3 or YAG single crystals, leading to increased thermal effects and reduced efficiency.
Innovation Solution
The illumination device features a light guide with a second light guiding portion having a light emitting surface where the intersecting line of the emitting surface and the cross-section forms an acute angle with the center line, reducing the incidence angle and total internal reflection, and includes a functional layer for wavelength conversion or scattering, along with a heat dissipation layer for improved thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If materials with high thermal conductivity and high refractive index (such as Al2O3 single crystal or YAG single crystal) are used for the light guide, then heat dissipation performance is improved, but total internal reflection increases causing low light utilization rate
Solution Approach 1:
The patent applies local quality by differentiating the optical properties of different regions within the light guide. The first light guide portion has a first refractive index while the second light guide portion has a second refractive index that is lower than the first. This creates local optical property variations that allow different portions of the light guide to perform different functions: the first portion efficiently guides light with high total internal reflection, while the second portion allows light extraction with reduced total internal reflection, thereby resolving the contradiction between heat dissipation and light utilization.
Solution Approach 2:
The light guide is segmented into multiple portions with different refractive indices. The patent divides the light guide into a first light guide portion and a second light guide portion, where each portion has distinct optical properties. This segmentation allows the system to simultaneously achieve high heat dissipation (through materials like Al2O3 or YAG) while managing total internal reflection effects by having different refractive index zones, thus improving overall light utilization rate.
2Ease of manufacture
If the light guide uses a single refractive index material, then manufacturing is simplified, but light extraction efficiency is reduced due to total internal reflection
Solution Approach 1:
The patent implements local quality by creating regions with different refractive indices within the light guide structure. The first light guide portion has a first refractive index and the second light guide portion has a second refractive index lower than the first. This allows the system to maintain manufacturing feasibility while significantly improving light extraction efficiency in the second portion where reduced total internal reflection occurs, thus resolving the contradiction between manufacturing simplicity and light extraction efficiency.
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 enhances light emission efficiency and utilization rates by reducing reflections and thermal effects, while effectively utilizing more light and improving heat dissipation, resulting in a more efficient and effective illumination system.
Implementation Method 1
Due to a high refractive index of the Al2O3 single crystal or YAG single crystal, a total internal reflection angle at its interface is relatively small. When light rays are transmitted to a light emitting end of the illumination device, only fewer light rays that do not meet the total internal reflection angle are emitted to outside through the light emitting end to achieve illumination, however, more light rays satisfying the total internal reflection angle cannot be directly emitted from the light emitting end to the outside, and this results in multiple total internal reflections of a light beam inside the illumination device
Implementation Method 2
a functional layer coated on the light emitting surface of the second light guiding portion and configured to perform a wavelength conversion on the excitation light or scatter the excitation light, to form illumination light
Implementation Method 3
a functional layer coated on the light emitting surface of the second light guiding portion and configured to perform a wavelength conversion on the excitation light or scatter the excitation light
Data Source
AI summary
An illumination device includes a light source and a light guide including a first light guide portion and a second light guide portion. The second light guide portion contains a light-emitting face, and the excitation light emitted by the light source is coupled and enters the first light guide portion and is emitted via the light-emitting face of the second light guide portion. The area of the cross section, perpendicular to a light guide central line, of the second light guide portion is gradually decreased in the direction of an optical axis of the light source. An angle between an intersecting line of the light-emitting face of the second light guide portion and the cross section passing through the light guide central line or any tangent line of the intersecting line and the light guide central line is an acute angle.