LED Wavelength Conversion Layer Viscosity Control
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Solution Overview
Problem
Existing methods for manufacturing white LEDs face challenges such as color unevenness due to fluorescent substance settlement and inadequate durability of sealant materials, leading to inefficiencies in heat and light durability.
Innovation Solution
A method involving the use of a fluorescent substance dispersion liquid and a precursor solution containing an organometallic compound, layered silicate mineral, and inorganic fine particles, applied separately to form a wavelength conversion portion with high heat durability, where the fluorescent substance is evenly dispersed in a translucent ceramic layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a fluorescent substance is dispersed in a transparent resin to form white LEDs, then white light emission is achieved, but the fluorescent substance settles before the resin hardens causing color unevenness
Solution Approach 1:
A viscosity-increasing agent is introduced as an intermediary substance into the resin composition to increase its viscosity and prevent fluorescent substance settlement. This mediator allows the resin to maintain both its transparency for light emission and sufficient viscosity to keep the fluorescent particles uniformly distributed throughout the curing process.
Solution Approach 2:
The viscosity of the resin is dynamically adjusted by adding a viscosity-increasing agent, changing the physical parameter of the resin from low viscosity (prone to settlement) to high viscosity (settlement-resistant). This parameter change enables the resin to maintain uniform fluorescent substance distribution while still allowing proper curing and light transmission.
2Manufacturing precision
If silicone resin is used as a sealant to suppress fluorescent substance settlement, then color uniformity is improved, but the sealant deteriorates due to light and heat causing poor durability
Solution Approach 1:
The invention uses a composite resin composition combining transparent resin with a viscosity-increasing agent and dispersed fluorescent substance. This composite material achieves both the settlement suppression needed for color uniformity and the thermal/light stability required for durability, avoiding the degradation issues of pure silicone resin while maintaining its beneficial viscosity properties.
Solution Approach 2:
Rather than relying on silicone resin which has inherent durability limitations under LED operating conditions, the invention employs a more stable resin system with viscosity modification, effectively replacing a short-lived deteriorating material with a long-lived stable composite material that maintains performance over time.
3Manufacturing precision
If the viscosity of the sealant is increased to prevent fluorescent substance settlement, then color uniformity is improved, but the sealant becomes too viscous to apply properly
Solution Approach 1:
The viscosity-increasing agent is incorporated into the resin composition before the fluorescent substance is dispersed and before the curing process begins. This preliminary action ensures the resin has the appropriate viscosity from the start, allowing easy application and uniform dispersion of fluorescent particles, while the viscosity remains manageable throughout the manufacturing process.
Solution Approach 2:
The resin viscosity is optimized to a specific range through the addition of viscosity-increasing agent, creating a balance where the viscosity is high enough to prevent settlement but low enough to allow proper application and spreading. This parameter optimization enables both manufacturability and color uniformity simultaneously.
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 method ensures even dispersion of the fluorescent substance, reducing color unevenness and enhancing the heat and light durability of the light-emitting device, while maintaining a stable viscosity to prevent premature settlement.
Implementation Method 1
a viscosity-increasing agent (a layered compound mainly composed of a clay mineral) is added to a translucent resin
Implementation Method 2
heating the precursor solution applied on the fluorescent substance layer
Implementation Method 3
applying a precursor solution including an organometallic compound on the light-emitting; and heating the precursor solution applied on the fluorescent substance layer
Implementation Method 4
a fluorescent substance which is excited by the light emitted from the light-emitting element so as to emit (generate) fluorescence of a wavelength different from the predetermined wavelength
Data Source
AI summary
A method of manufacturing a light-emitting device includes forming a wave length conversion portion on a light-emitting element. The light emitting device includes a light-emitting element which emits light of a predetermined wavelength and a wavelength conversion portion which includes a fluorescent substance which is excited by the light emitted from the light-emitting element so as to emit fluorescence of a wavelength different from the predetermined wavelength, which wavelength conversion portion is formed by including the fluorescent substance, a layered silicate mineral, and an organometallic compound. The forming the wavelength conversion portion includes forming a fluorescent substance layer on the light-emitting element using a fluorescent substance dispersion liquid including a fluorescent substance and a layered silicate mineral, applying a precursor solution including an organometallic compound on the light-emitting element, and heating the precursor solution applied on the fluorescent substance layer.