Linear Light Source Lens with Sawteeth Microstructure

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Solution Overview

Problem

Existing strip illuminating devices face challenges in achieving uniform elongated light distribution due to the thickness and geometrical constraints of TIR extrusion lenses and the inability of column stripe lenses to control light of different incident angles effectively.

Innovation Solution

A lens design featuring a central convex region flanked by symmetrical second concave regions with a continuous sawteeth-like microstructure, allowing for adjustable internal reflection and refraction to achieve uniform light distribution, where the sawteeth units have varying shapes and angles to direct light to a predetermined direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If TIR extrusion lens is used to achieve light distribution control, then light distribution is improved, but lens thickness increases making it inapplicable in environments with strict geometrical constraints

Engineering Contradiction:
Improvelight distributionVSAvoidlens thickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The lens surface is divided into multiple functional zones: a first convex region, second concave regions with continuous sawteeth microstructure, and edge regions. This segmentation allows different parts of the lens to control light in different ways, achieving effective light distribution with reduced overall thickness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the lens are assigned different optical functions and structural characteristics. The second concave regions with sawteeth microstructure provide total internal reflection for specific light angles, while the first convex region and edge regions handle other light paths differently, optimizing local light control to achieve overall uniform distribution

Inventive Principle:
Principle #3Local quality

2Length of stationary object

If lens with column stripes is used to reduce thickness, then lens thickness is reduced, but uniform light distribution cannot be achieved because column strips are uniformly distributed and cannot control light of different incident angles

Engineering Contradiction:
Improvelens thicknessVSAvoiduniform light distribution
Core Design Contradiction:
Length of stationary objectVSIllumination intensity

Solution Approach 1:

The lens employs non-uniform regional design where the second concave regions contain continuous sawteeth microstructure with varying shapes and angles, while the first convex region and edge regions have different structures. This local differentiation enables effective control of light from different incident angles, achieving uniform light distribution

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The lens uses curved surfaces including convex and concave regions with specific radii of curvature. The continuous sawteeth microstructure is formed on arched shapes with specific curvature characteristics, enabling effective light control while maintaining a compact, thin profile

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of manufacture

If sawteeth with constant height are used in microstructure, then manufacturing is simplified, but light control precision is reduced

Engineering Contradiction:
Improvemicrostructure fabricationVSAvoidlight control precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The continuous sawteeth microstructure features varying heights and angles in different locations rather than uniform constant dimensions. This local variation allows precise control of light reflection angles for different incident light paths, improving light distribution uniformity while remaining manufacturable

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sawteeth microstructure parameters (height, angle, spacing) are varied continuously or in controlled steps across different regions of the lens. This parameter variation enables precise optical control by matching the microstructure characteristics to the specific light control requirements of each lens region

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

This design enables a high optical efficiency and uniform elongated light distribution, suitable for environments with strict geometrical constraints, by optimizing the internal reflection and refraction of light within the lens.

Implementation Method 1

respective second concave region 2 that mainly receives light from the light source L has a microstructure, i.e., a continuous sawteeth-like structure consisting of a plurality of total internally reflective sawteeth-like units T

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

the small angle part emergent light is refracted in lens

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2771730B1A lens and an illuminating device equipped with the lens
Publication Date: 2021.08.25 SITECO GMBH
  • EP2771730B1 patent drawingFigure 1~2
  • EP2771730B1 patent drawingFigure 3
  • EP2771730B1 patent drawingFigure 4~5

AI summary

The present invention relates to a lens for a linear light source (L), comprising an outer surface facing away the light source (L) and an inner surface facing to the light source (L), wherein the outer surface is a planar emergent surface (F) and the inner surface comprises a first convex region (1) and second concave regions (2), symmetrical with respect to the first convex region (1), wherein respective second concave region (2) has a microstructure, through which light from the light source (L) is refracted and further reflected to the emergent surface (F). In addition, the present invention further relates to an illuminating device equipped with the lens. The lens according to the present invention has a small thickness and can totally refract and internally reflect light of different incident angles so as to create an elongated uniform light distribution pattern.