White LED Lamp UV-Phosphor Conversion for Resin Protection

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Solution Overview

Problem

Conventional white LED lamps of Type 3 suffer from issues such as yellow discoloration of resin components in liquid crystal display devices and potential damage to illuminated objects due to unconverted UV light and heat, limiting their use in backlighting and illumination applications.

Innovation Solution

A white LED lamp design featuring a light emitting diode chip emitting UV to violet light with a peak wavelength of 360-420 nm, a transparent resin layer, and a phosphor layer composed of dispersed phosphor powder that converts the primary light into a secondary light with a longer wavelength, minimizing UV emission and heat generation, and incorporating a UV-absorbing layer to further suppress UV output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a UV light or violet light emitting diode chip with red, green and blue phosphors is combined to emit white light, then the color reproducing property is wide and the color rendering property is excellent, but unconverted UV light and heat cause yellow discoloration of resin components and potential damage to illuminated objects

Engineering Contradiction:

Improvecolor rendering propertyVSAvoidUV light damage and heat generation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful UV light into beneficial visible light by introducing a UV-absorbing phosphor material that absorbs UV radiation and emits blue light, transforming the harmful UV energy into useful illumination while preventing resin discoloration and object damage

Inventive Principle:

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

Solution Approach 2:

The patent introduces a UV-absorbing phosphor layer as an intermediary between the UV/violet LED chip and the other phosphor materials, which absorbs the harmful UV light and converts it to blue light, preventing direct UV exposure to resins and illuminated objects while contributing to white light generation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If phosphor powder is dispersed in transparent resin to convert UV light to visible light, then white light is emitted with high luminous efficiency, but resin components undergo yellow discoloration due to UV exposure and heat

Engineering Contradiction:

Improveluminous efficiencyVSAvoidresin color stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent converts harmful UV light that causes resin yellowing into useful blue light through a UV-absorbing phosphor, eliminating the harmful effect while maintaining and enhancing the luminous efficiency by utilizing the converted light in the visible spectrum

Inventive Principle:

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

Solution Approach 2:

The patent extracts and removes the harmful UV component from the light spectrum by using a UV-absorbing phosphor that selectively absorbs UV radiation, preventing it from reaching and damaging the resin while converting it to beneficial blue light

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If a blue light emitting diode chip with yellow phosphor is combined to emit white light, then the structure is simple, but the color reproducing property is narrow and color rendering is poor

Engineering Contradiction:

Improvestructure simplicityVSAvoidcolor reproducing property

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The patent uses a composite phosphor system combining UV-absorbing phosphor, blue phosphor, green phosphor, and red phosphor to create a multi-component material system that achieves superior color rendering while maintaining structural simplicity through a single integrated LED package design

Inventive Principle:

Principle #40Composite materials

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 significantly reduces UV emission and heat generation, preventing yellow discoloration and damage, while maintaining high luminous efficiency and energy efficiency, making the white LED lamp suitable for both liquid crystal display devices and illumination applications like art galleries.

Implementation Method 1

the phosphor powder receives the UV light to violet light and emits a secondary light having a wavelength longer than that of the primary light

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

incorporating a UV-absorbing layer to further suppress UV output

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS10886434B2White LED lamp, backlight, light emitting device, display device and illumination device

Publication Date: 2021.01.05 SEOUL SEMICONDUCTOR

AI summary

A white LED lamp including: a conductive portion; a light emitting diode chip mounted on the conductive portion, for emitting a primary light having a peak wavelength of 360 nm to 420 nm; a transparent resin layer including a first hardened transparent resin, for sealing the light emitting diode chip; and a phosphor layer covering the transparent resin layer, the phosphor layer being formed by dispersing a phosphor powder into a second hardened transparent resin, and the phosphor powder receiving the primary light and radiating a secondary light having a wavelength longer than that of the primary light. An energy of the primary light contained in the radiated secondary light is 0.4 mW/lm or less.