Light-Reflecting Material for LED Lighting Devices

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing LED reflectors face issues with poor processability, heat resistance, and short lifespan due to materials like ceramics and unsaturated polyester resins, which lead to discoloration and reduced luminance over time.

Innovation Solution

A light reflector material comprising uncrystallized unsaturated polyester resin, thermosetting resin, and white-based pigments like titanium oxide, with a specific mass ratio of diallyl phthalate and isophthalate, and inorganic fillers, to enhance heat resistance, light resistance, and processability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If ceramics are used for LED reflector, then heat resistance is improved, but processability deteriorates

Engineering Contradiction:
Improveheat resistanceVSAvoidprocessability
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention uses a composite material system consisting of unsaturated polyester resin as the base polymer, combined with specific crosslinking agents (diallyl phthalate, diallyl isophthalate) and inorganic fillers (titanium oxide, zinc oxide, barium sulfate). This composite approach achieves both heat resistance through crosslinking and processability through thermosetting characteristics, resolving the contradiction between ceramics' heat resistance and poor processability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical and physical parameters of the resin system by controlling the molecular structure of unsaturated polyester resin, adjusting crosslinking density through specific crosslinking agents, and optimizing filler content and particle size distribution. These parameter changes enable the material to achieve ceramic-like heat resistance while maintaining moldability and processing advantages.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If unsaturated polyester resin is used for LED reflector, then processability is improved, but heat resistance deteriorates

Engineering Contradiction:
ImproveprocessabilityVSAvoidheat resistance
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The invention utilizes the phase transition characteristics of unsaturated polyester resin during curing. The resin transitions from a liquid or soft state during molding (ensuring processability) to a crosslinked thermosetting state after curing (providing heat resistance). This phase transition enables the material to exhibit different properties during different stages of the product lifecycle.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The invention changes the chemical parameters of the resin by introducing crosslinking agents that form three-dimensional networks. The crosslinking density is controlled by adjusting the ratio of crosslinking agents (diallyl phthalate, diallyl isophthalate) to resin, thereby achieving optimal balance between processability and heat resistance.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional resin materials are used for LED reflector, then processability is improved, but light resistance deteriorates

Engineering Contradiction:
ImproveprocessabilityVSAvoidlight resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention introduces inorganic fillers (titanium oxide, zinc oxide, barium sulfate) as intermediaries between the resin matrix and light exposure. These fillers serve multiple functions: they scatter and reflect light to maintain luminance, they provide UV resistance to prevent resin degradation, and they enhance the overall light resistance of the reflector while maintaining processability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite material system where unsaturated polyester resin provides processability and structural integrity, while inorganic fillers provide light resistance and UV stability. This composite approach allows the reflector to maintain both manufacturing advantages and long-term optical performance.

Inventive Principle:
Principle #40Composite materials

4Temperature

If high filler content is added to resin, then heat resistance is improved, but manufacturing precision deteriorates

Engineering Contradiction:
Improveheat resistanceVSAvoiddimensional accuracy
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The invention applies local quality control by using filler particles with specific size distributions and surface treatments. Different filler sizes are distributed throughout the resin matrix to optimize both heat resistance and dimensional stability. The filler surface is treated to improve bonding with the resin, preventing filler-induced warping and sink marks.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the physical parameters of the filler system by controlling particle size, shape, and surface properties. The filler content is optimized within specific ranges to achieve sufficient heat resistance without excessive filler that would cause warping. The resin-filler interface is engineered through surface treatment to minimize dimensional deviations during curing.

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 results in a material with high dimensional accuracy, excellent heat and light resistance, and improved processability, reducing warp and sink issues, and extending the lifespan of LED lighting devices.

Implementation Method 1

a light reflector material... comprising at least thermosetting resin and a white-based pigment... wherein the material has high dimensional accuracy, excellent heat and light resistance

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

white-based pigment wherein the white-based pigment is at least one selected from the group consisting of titanium oxide... excellent light resistance

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentEP3306359B1Light-reflecting material, light-reflecting body and lighting device
Publication Date: 2020.03.04 OTSUKA CHEMICAL CO LTD
  • EP3306359B1 patent drawingFigure 1

AI summary

The present invention provide a light reflector material having less warp or sink, high dimensional accuracy, excellent heat resistance, excellent light resistance, excellent weather resistance (having little discoloration by heat and/or light), excellent impact resistance, and excellent processability. The light reflector material comprises at least thermosetting resin and a white-based pigment; wherein the thermosetting resin is comprised by using at least uncrystallized unsaturated polyester resin and diallyl phthalate, and/or diallyl isophthalate {50/50 (mass ratio) ≤(the diallyl phthalate and/or diallyl isophthalate)/(the uncrystallized unsaturated polyester resin)}.