Stepped Deflection Light Guide for Homogeneous Illumination
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Solution Overview
Problem
Existing light guides for motor vehicle lighting devices often result in non-homogeneous illumination and deviations from desired light beam distribution, especially when the light-emitting surface is curved or angled, leading to intensity differences and improper parallelization of light beams.
Innovation Solution
A light guide with a flat, thin-walled design featuring wide side faces, a paralleling section for parallelizing light, a stepped deflection section with reflection and offset surfaces, and a decoupling section that ensures constant intensity and homogeneous illumination along a curved or elongated light decoupling surface, using total internal reflection and strategic placement of reflection and offset surfaces to direct light uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the light-emitting surface is curved or angled to achieve design freedom and stylistic appearance, then the aesthetic and design requirements are met, but homogeneous illumination is lost and intensity differences occur along the light-emitting surface
Solution Approach 1:
The deflection surface is divided into multiple discrete deflection elements arranged in sequence along the light path. Each deflection element can be independently optimized to control the direction and distribution of light rays, allowing the light to be uniformly distributed across a curved or angled light-emitting surface while maintaining design freedom
Solution Approach 2:
Different regions of the light guide are optimized for different functions: the input region focuses on light coupling, the deflection region uses specifically shaped deflection elements to control light distribution, and the output region is designed to achieve the desired curved or angled light-emitting surface. Each region's optical properties are tailored to its specific requirement
2Adaptability or versatility
If the light-emitting surface is positioned with a pronounced swept-back angle to meet design requirements, then the stylistic appearance is achieved, but the light distribution deviates from the desired parallel pattern
Solution Approach 1:
The deflection elements are designed with specific curved surfaces that refract light rays at controlled angles. By optimizing the curvature and shape of these elements, the light can be redirected to maintain a parallel distribution pattern even when the light-emitting surface is positioned at a pronounced swept-back angle
3Adaptability or versatility
If existing light guide designs are used to achieve curved or angled light-emitting surfaces, then design flexibility is improved, but significant intensity differences and deviations from parallel light distribution occur
Solution Approach 1:
The optical parameters of the deflection elements (refractive index, surface curvature, element spacing, element shape) are systematically optimized to compensate for the effects of curved or angled light-emitting surfaces. By adjusting these parameters, uniform light intensity and parallel distribution are achieved despite the geometric complexity of the output surface
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 homogeneous illumination and desired light beam distribution along the light decoupling surface, even when it has a curved or multi-curved shape, by compensating for spatial intensity variations and minimizing Fresnel losses through the strategic arrangement of reflection and offset surfaces, allowing for a strong sweep in the vehicle's lighting design.
Implementation Method 1
The parallelization section (24) has a light input area (30) for supplying the optical fiber (14) with light. It is designed to parallelize the light supplied through the light input area (30), i.e., to transform it into a light distribution which, when projected onto the surface of the parallelization section (24), consists essentially of parallel light rays.
Implementation Method 2
The deflection surface is multi-part and stepped. It comprises a plurality of reflective surfaces and a plurality of offset surfaces. The reflective surfaces are designed to reflect light rays towards the output section.
Data Source
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AI summary
The invention relates to a planar light guide (14) which has a parallelization section (24), a deflection section (26) adjoining the beam path and an output section (28) adjoining the latter, wherein the parallelization section (24) has a light introduction area (30) and is configured to parallelize the light supplied through the light introduction area (30), wherein the output section (28) has a narrow light output area (38) extending between the wide light guide surfaces (16, 18), and wherein the deflection section (26) has a deflection surface (44) which is formed on a narrow side surface extending from the parallelization section (24) to the output section (28) and is configured to deflect the light coming from the parallelization section (24) to the output section (28).To improve the illumination of the light output area, the deflection surface (44) comprises a plurality of reflective surfaces (46) for reflecting light rays to the output section (28) and a plurality of offset surfaces (48), wherein at least one offset surface (48) is arranged between each pair of reflective surfaces (48) such that the reflective surfaces (48) are arranged in a step-like manner along the path of the deflection surface (44) from the parallelization section (24) to the output section (28). The invention also relates to a light guide structure based thereon, as well as a vehicle lighting device (10).