LED Lens with Elliptical Back Surface for Light Direction

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Solution Overview

Problem

Existing LED lighting fixtures suffer from inefficient light distribution due to the loss of light emitted at undesirable angles, leading to less than desirable illumination patterns and reduced efficiency, as prior lenses often block or fail to effectively refract light in desired directions.

Innovation Solution

A lens design with distinct refractive configurations for light emitted at different angles, utilizing total internal reflection and elliptical cross-sections to direct a greater proportion of light towards a preferential side without separate reflectors, enhancing light output efficiency and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If prior lenses block light emitted at undesirable angles, then illumination pattern control is improved, but light output efficiency deteriorates

Engineering Contradiction:
Improveillumination pattern controlVSAvoidlight output efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent converts light emitted at previously undesirable angles into beneficial illumination by using the lens geometry to refract these rays into useful directions. The lens design transforms what was considered waste light into contributing photons that reach the target area, thereby improving overall light output efficiency while maintaining pattern control.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the refractive parameters of the lens surfaces to optimize light direction. By carefully designing the curvature and refractive index distribution, the lens achieves superior control over light emitted at various angles, redirecting more light toward the desired illumination area while minimizing losses.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If prior lenses refract light from wide emission angles, then light distribution is improved, but directional control deteriorates

Engineering Contradiction:
Improvelight distributionVSAvoiddirectional control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies different refractive properties to different regions of the lens. The lens design incorporates varying curvature and refractive index characteristics in different zones to handle light from wide emission angles differently, achieving both broad light distribution and precise directional control simultaneously.

Inventive Principle:
Principle #3Local quality

3Productivity

If separate reflectors are added to direct light, then illumination efficiency is improved, but device complexity deteriorates

Engineering Contradiction:
Improveillumination efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the functions of light refraction and reflection into a single integrated lens structure. By combining these optical functions into one component rather than using separate reflectors, the design achieves improved illumination efficiency while reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 achieves improved light distribution efficiency, directing up to 10% more light towards the intended area, effectively utilizing 90% of emitted light for enhanced illumination, compared to prior designs.

Implementation Method 1

The front sector has a first configuration for refracting light from the emitter. The back sector has a second configuration for refracting light from the emitter.

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

an axially-offset primary back surface positioned to receive light from at least a portion of the inner-surface back sector and configured for total internal reflection (TIR) thereof. Light from the primary back surface is directed toward the preferential side.

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2435756B1Lens with controlled backlight management
Publication Date: 2019.07.24 IDEAL IND LIGHTING LLC
  • EP2435756B1 patent drawingFigure 1
  • EP2435756B1 patent drawingFigure 2~3
  • EP2435756B1 patent drawingFigure 4

AI summary

A lens distributing light, predominantly toward a preferential side, from a light emitter having an emitter axis and defining an emitter plane has an emitter-adjacent base end forming an emitter-receiving opening to an emitter-surrounding cavity having an inner surface which includes a front sector centered on the preferential side and a back sector centered on the radially opposite non-preferential side. The front and back sectors differ in their respective configurations for refracting light from the emitter. The lens further includes an primary back surface positioned and configured to receive and totally reflect light from at least a portion of the inner-surface back sector The inner-surface back sector and the primary back surface extend along substantially elliptical cross-sections in planes substantially parallel to the emitter plane. The base end forms a back opening to a back cavity substantially centered on the non-preferential side and partially bounded by the primary back surface