Asymmetrical Light Distribution Lens for Linear LED Sources

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Solution Overview

Problem

Existing asymmetrical light distribution luminaires using T5 fluorescent lamps struggle to achieve the desired asymmetrical light distribution when replaced with LED linear light sources, as existing wallwasher reflectors are inadequate for creating the necessary light distribution effect.

Innovation Solution

A lens for linear LED light sources featuring a top and bottom structure with an incident surface, supporting surfaces, and a total internally reflective surface, where the emergent surface is joined with the supporting surfaces to refract and reflect light, allowing for asymmetrical light distribution by offsetting light over a predetermined angle relative to the optical axis, reducing lens size and ensuring complete light entry without loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing wallwasher reflectors are used with LED linear light sources, then energy consumption is reduced and service lifetime is extended, but asymmetrical light distribution effect cannot be achieved

Engineering Contradiction:
Improveservice lifetimeVSAvoidasymmetrical light distribution effect
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the optical parameters by introducing a total internally reflective surface with specific geometric configuration (inclined at an angle greater than 45 degrees relative to the optical axis) and specific reflective properties. This transforms the optical system from one that cannot produce asymmetrical distribution to one that can, while maintaining LED energy efficiency and longevity benefits

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The total internally reflective surface acts as an intermediary element between the LED linear light source and the emergent surface. It mediates the light path by reflecting a portion of the light at specific angles, enabling asymmetrical light distribution without requiring replacement of the LED source or use of traditional reflectors

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a lens with total internally reflective surface is designed to achieve asymmetrical light distribution, then light distribution effectiveness is improved, but lens structure complexity increases

Engineering Contradiction:
Improveasymmetrical light distributionVSAvoidlens structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the refractive function (emergent surface) and reflective function (total internally reflective surface) into a single integrated lens structure. This combination achieves asymmetrical light distribution without requiring separate reflector components, thereby reducing overall system complexity while maintaining the desired optical effect

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lens employs asymmetrical geometric configuration, particularly the total internally reflective surface inclined at an angle greater than 45 degrees relative to the optical axis, and the asymmetrical arrangement of incident and emergent surfaces. This asymmetry directly enables the asymmetrical light distribution effect while maintaining a relatively simple single-lens structure

Inventive Principle:
Principle #4Asymmetry

3Volume of stationary object

If the total internally reflective surface is formed to be inclined with respect to the optical axis, then lens size is reduced and light reflection efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvelens sizeVSAvoidinclination angle precision
Core Design Contradiction:
Volume of stationary objectVSManufacturing precision

Solution Approach 1:

The patent specifies a particular parameter range for the inclination angle (greater than 45 degrees) of the total internally reflective surface. By defining this specific parameter range, the patent optimizes the balance between lens size reduction, light reflection efficiency, and manufacturing feasibility, making the precision requirement manageable while achieving compact design

Inventive Principle:
Principle #35Parameter changes

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 lens effectively achieves asymmetrical light distribution for better illumination of exhibited contents, similar to traditional asymmetrical light distribution luminaires, while accommodating the LED light source within a compact design, ensuring all light is directed to a predetermined angle for optimal illumination.

Implementation Method 1

one part of light from the linear light source incidents into the incident surface and emerges after refracted by the emergent surface

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

the other part of light incidents into the incident surface and reflected by the total internally reflective surface and than emerges after refracted by the emergent surface

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2771729B1A lens and an asymmetrical light distribution illuminating device having such lens
Publication Date: 2021.04.14 SITECO GMBH
  • EP2771729B1 patent drawingFigure 1~2
  • EP2771729B1 patent drawingFigure 3
  • EP2771729B1 patent drawingFigure 4

AI summary

The present invention relates to a lens for a linear light source comprising a top and a bottom, the bottom comprising an incident surface (1), and a first supporting surface (4a) and a second supporting surface (4b) at both sides of the incident surface (1), and the top comprising an emergent surface (2), wherein the top further comprises a total internally reflective surface (3), and wherein in a cross section, the emergent surface (2) is connected with the first supporting surface (4a), the total internally reflective surface (3) is connected with the second supporting surface (4b), one part of light from the linear light source emerges after refracted by the incident surface (1) and the emergent surface (2), and the other part of light is refracted by the incident surface (1) to the total internally reflective surface (3) to be total internally reflected and emerges after refracted by the emergent surface (2). In addition, the present invention further relates to an asymmetrical light distribution illuminating device having such lens.