Linear Light Guide Uniformity via Local Quality
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Solution Overview
Problem
Conventional vehicle lamps with laser light sources and light guides suffer from non-uniform light emission, which decreases with longer light guide lengths, necessitating a solution for improved light uniformity.
Innovation Solution
A linear lighting device comprising a laser light source, a wavelength converter (phosphor body) that converts laser light, and an elongated linear light guide with a lateral surface that emits wavelength-converted light, where the proportion of emitted light increases with optical path length, utilizing an uneven surface structure to enhance light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the light guide is made longer to extend the lighting coverage, then the lighting area is increased, but the uniformity of light emission deteriorates
Solution Approach 1:
The patent applies local quality by making the light extraction properties non-uniform along the light guide. Specifically, the light guide has a first region with a first light extraction ratio and a second region with a second light extraction ratio that is different from the first. This allows different portions of the light guide to have optimized extraction characteristics, enabling uniform overall light emission while maintaining a longer lighting area.
Solution Approach 2:
The patent changes the parameter of light extraction ratio along the length of the light guide. By varying the light extraction ratio between different regions (first region vs. second region), the patent optimizes light distribution to achieve uniform emission across the entire extended lighting area, resolving the contradiction between area extension and uniformity maintenance.
2Illumination intensity
If the light extraction ratio is increased to improve light emission, then the light uniformity is improved, but the light guide length must be limited which restricts the lighting area
Solution Approach 1:
The patent segments the light guide into distinct regions (first region and second region) with different light extraction ratios. This segmentation allows each region to be optimized independently for light extraction, enabling the overall system to achieve both high light emission uniformity and extended lighting area without the trade-off that would exist in a uniform light guide design.
3Illumination intensity
If the light guide is made shorter to maintain uniform light emission, then the light uniformity is improved, but the lighting coverage area is reduced
Solution Approach 1:
By implementing different light extraction ratios in different regions of the light guide, the patent enables the light guide to be made longer while maintaining uniform light emission. The local optimization of extraction properties compensates for the increased length, allowing extended lighting coverage without sacrificing uniformity.
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 highly uniform light emission with reduced luminance unevenness, allowing for efficient light distribution across the light guide's length.
Implementation Method 1
a wavelength converter that converts a wavelength of the laser light and emits wavelength-converted light
Implementation Method 2
a linear light guide that is elongated and guides the wavelength-converted light emitted by the wavelength converter and introduced through a longitudinal end surface
Data Source
AI summary
A lighting device includes a laser light source that emits laser light, a wavelength converter that converts a wavelength of the laser light and emits wavelength-converted light, and a linear light guide that is elongated and guides the wavelength-converted light emitted by the wavelength converter and introduced through a longitudinal end surface. The linear light guide includes a lateral surface that emits the wavelength-converted light guided by the linear light guide. A proportion of the wavelength-converted light emitted by the lateral surface gradually increases with an increase in optical path length in the linear light guide.