Wavelength-Selective Lens in LED Lighting Modules for Uniform Emission

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Solution Overview

Problem

Conventional lighting modules using light emitting diodes (LEDs) face challenges in achieving high light extraction efficiency and forming a uniform surface light source due to the phosphor layer, which leads to light loss and reduced visibility.

Innovation Solution

A lighting device is designed with a lens disposed on the phosphor layer to block shorter wavelengths and transmit longer wavelengths, improving light extraction efficiency and achieving a uniform surface light source by optimizing the phosphor content and lens configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a high-density phosphor layer is disposed on the light emitting device to form a uniform surface light source, then the uniformity of surface light source is improved, but the light extraction efficiency is lowered due to light reflection and absorption

Engineering Contradiction:

Improveuniformity of surface light sourceVSAvoidlight extraction efficiency

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

A resin layer with optimized refractive index is introduced as an intermediary between the light emitting devices and the phosphor layer. This resin layer mediates the optical interaction, reducing light reflection and absorption at the interfaces while still allowing the phosphor layer to convert light wavelengths effectively, thus maintaining uniform surface light source without excessive light loss

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The refractive index of the resin layer is specifically optimized and adjusted to match the optical properties of the phosphor layer. By changing this physical parameter, the optical impedance mismatch is reduced, minimizing light reflection and absorption at the phosphor layer interface, thereby improving light extraction efficiency while preserving surface uniformity

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If a low-density phosphor layer is disposed to prevent decrease in light extraction efficiency, then the light extraction efficiency is improved, but it is difficult to form a uniform surface light source

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoiduniformity of surface light source

Core Design Contradiction:

Loss of energyVSStability of the object's composition

Solution Approach 1:

The optimized resin layer acts as a mediator that enables the low-density phosphor layer to achieve both high light extraction efficiency and uniform surface light distribution. The resin layer compensates for the reduced light conversion capacity of the low-density phosphor by providing optimal optical coupling and light distribution

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By optimizing the refractive index parameter of the resin layer, the system achieves enhanced light extraction from the low-density phosphor layer while the resin itself contributes to uniform light distribution across the surface, thus achieving both goals simultaneously

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the phosphor content is increased to improve light conversion, then the light extraction efficiency decreases due to increased light absorption

Engineering Contradiction:

Improvelight conversion efficiencyVSAvoidlight extraction efficiency

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The refractive index of the resin layer is optimized to reduce optical reflection and absorption at the phosphor layer interfaces. This parameter change allows for improved light extraction efficiency even when phosphor content is increased for better light conversion, as the optimized optical coupling minimizes energy loss

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 solution enhances light extraction efficiency and prevents light loss, resulting in improved visibility and a uniform surface light distribution, while reducing the phosphor content to prevent hot spots and maintain design flexibility.

Implementation Method 1

a phosphor layer disposed on the resin layer to convert the first light into the second light

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

a lens disposed on the lighting module to block light of a shorter wavelength among the first light and the second light and transmit light of a longer wavelength

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS12191428B2Lighting module and lighting device comprising same

Publication Date: 2025.01.07 LG INNOTEK CO LTD

AI summary

A lighting device disclosed in an embodiment of the invention includes: a lighting module emitting a first light and a second light; and a lens disposed on the lighting module to block light of a shorter wavelength among the first light and the second light and transmit light of a longer wavelength, wherein the lighting module includes: a substrate; a plurality of light emitting devices disposed on the substrate and emitting a first light; a resin layer covering the plurality of light emitting devices; and a phosphor layer disposed on the resin layer to convert the first light into second light, wherein the first and second light travel through the phosphor layer in the lens direction, and the second light may pass through the lens.