Fresnel Lens Acute-Angle Ineffective Surface Stray Light
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Solution Overview
Problem
Existing Fresnel lenses suffer from stray light issues due to ineffective surfaces that cause light to scatter at large angles, affecting the uniformity of light emission in LED lighting applications.
Innovation Solution
A Fresnel lens design where ineffective surfaces are inclined at an acute angle relative to the optical axis, with specific angle relationships between effective and ineffective surfaces to minimize light passage through ineffective surfaces, ensuring most light is refracted by effective surfaces, thereby reducing stray light and enhancing light uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ineffective surfaces are made parallel to the optical axis in common Fresnel lenses, then the lens structure is simple and easy to manufacture, but light scatters at large angles forming stray light and reducing light uniformity
Solution Approach 1:
The patent applies asymmetry by inclining the ineffective surfaces at an acute angle relative to the optical axis, breaking the symmetric parallel arrangement. This asymmetric inclination causes light rays to be refracted at smaller angles, preventing them from scattering at large angles and forming stray light, while still maintaining manufacturing feasibility through a systematic angular design
2Object-generated harmful factors
If ineffective surfaces are inclined at an acute angle to reduce stray light, then light uniformity is improved, but the lens structure becomes more complex
Solution Approach 1:
The patent applies parameter changes by systematically varying the inclination angle of ineffective surfaces within a specific range (acute angle relative to the optical axis). By controlling this geometric parameter, the lens achieves reduced stray light through precise angular relationships between effective and ineffective surfaces, while the systematic parameter approach keeps the overall structure manageable and not excessively complex
3Device complexity
If light passes through ineffective surfaces at large angles, then the lens can be simpler in design, but light uniformity deteriorates due to scattering
Solution Approach 1:
The patent applies local quality by differentiating the functional characteristics of different surface regions. Effective surfaces are designed to refract light at specific angles for uniform distribution, while ineffective surfaces are inclined at acute angles to minimize light passage. This local differentiation ensures that light uniformity is improved by controlling light behavior in specific regions without requiring complete redesign of the entire lens structure
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 design significantly reduces stray light by controlling the inclination of ineffective surfaces, ensuring that light is directed effectively through the lens, resulting in improved light uniformity and reduced scattering.
Implementation Method 1
the light emitted from the light source is refracted through the light incident surface and penetrated into the lens body, and then refracted to the outside through the light exit surface
Data Source
AI summary
A Fresnel lens in a lens body, the lens body is provided with a light incident surface and a light exit surface opposite to each other along a first direction, and the light exit surfaces are adjacently arranged in a second direction perpendicular to the first direction. There are several protruding teeth, and the protruding teeth are formed by an effective surface and an ineffective surface, and the ineffective surface is inclined at an acute angle relative to the first direction. The invention makes the light passing through the lens body reach the effective surface as much as possible, thereby reducing stray light and enhancing light efficiency.