LED Phosphor Reflective Composite Wavelength Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high cost of phosphor materials in LED lighting devices due to the need for large quantities to achieve desired color properties, which increases production costs and thermal degradation issues.
Innovation Solution
Incorporating a mixture of photoluminescence materials with light reflective materials in a wavelength conversion component, which reduces the amount of phosphor material required by up to 50% by increasing photon collisions and scattering, allowing for omnidirectional emission and improved thermal management through a light transmissive circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphor materials are used in conventional LED devices to achieve desired color properties, then color quality is improved, but production cost increases due to high phosphor material costs
Solution Approach 1:
The patent introduces light reflective materials as an intermediary substance mixed with phosphor materials in the wavelength conversion layer. These reflective materials (such as titanium dioxide, barium sulfate, or zinc oxide particles) act as mediators that scatter and reflect light, increasing the path length of photons through the phosphor layer and enhancing phosphor excitation efficiency. This allows for reduced phosphor material quantity while maintaining color quality, thereby lowering production costs.
Solution Approach 2:
The patent creates a composite wavelength conversion layer by combining phosphor materials with light reflective materials in specific ratios (typically 90:10 to 70:30 by weight). This composite structure leverages the complementary properties of both materials: phosphors for wavelength conversion and reflective materials for light scattering and path extension. The composite formulation achieves optimal color properties with reduced phosphor content, addressing both color quality and cost concerns.
2Illumination intensity
If large quantities of phosphor materials are used to achieve desired color properties, then color quality is improved, but thermal degradation increases
Solution Approach 1:
Light reflective materials serve as thermal intermediaries by scattering light and reducing direct photon-phosphor interactions that generate heat. The reflective particles create multiple light paths, distributing energy more evenly and reducing localized thermal accumulation in the phosphor layer. This mitigates thermal degradation while maintaining color quality.
Solution Approach 2:
The patent modifies the compositional parameters of the wavelength conversion layer by reducing phosphor content and adding reflective materials. This parameter change alters the thermal properties of the layer, reducing heat generation from non-radiative recombination and improving thermal management. The optimized composition achieves better color quality with reduced thermal stress on the LED components.
3Area of moving object
If phosphor materials are applied directly to the LED die to reduce footprint, then device size is reduced, but phosphor material cost increases
Solution Approach 1:
The patent formulates a composite phosphor-reflective material mixture that can be applied as a thin, cost-effective layer directly on the LED die or circuit board. The reflective materials enhance light scattering within this thin layer, maximizing phosphor utilization efficiency. This allows for reduced phosphor quantity while maintaining effective wavelength conversion in a compact footprint, thereby reducing both device size and material cost.
4Illumination intensity
If remote phosphor configuration is used to increase footprint, then light distribution is improved, but phosphor material quantity and cost increase
Solution Approach 1:
The patent introduces light reflective materials as intermediaries in the remote phosphor configuration, creating a highly scattering medium that extends light paths and enhances phosphor excitation efficiency. This allows for effective light distribution across large areas with reduced phosphor quantity, as the reflective particles ensure multiple photon-phosphor interactions before light exits the remote phosphor layer.
Solution Approach 2:
The patent applies light reflective materials strategically within the remote phosphor layer to create zones of enhanced light scattering and phosphor excitation. By optimizing the local distribution and concentration of reflective particles, the patent achieves uniform light distribution across the entire remote phosphor area while minimizing total phosphor material requirements through localized efficiency enhancements.
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
This approach decreases phosphor material usage, enhances light generation efficiency, and reduces thermal degradation, while maintaining desired color properties and improving luminous efficacy.
Implementation Method 1
white LEDs include one or more photoluminescent materials (e.g., phosphor materials), which absorb a portion of the radiation emitted by the LED and re-emit radiation of a different color (wavelength)
Implementation Method 2
The inclusion of particles of a light reflective material with the phosphor material can increase photoluminescence light generation by the phosphor material. The increase in photoluminescence light generation is believed to result from the light reflective material increasing the probability of photon collisions with particles of the phosphor material.
Data Source
AI summary
A solid-state light emitting device comprises a light transmissive thermally conductive circuit board; an array of solid-state light emitters (LEDs) mounted on, and electrically connected to, at least one face of the circuit board; and a photoluminescence wavelength conversion component. The wavelength conversion component comprises a mixture of particles of at least one photoluminescence material (phosphor) and particles of a light reflective material. The emission product of the device comprises the combined light generated by the LEDs and the photoluminescence material. The wavelength conversion component can comprise a layer of the phosphor material and particles of a light reflective material applied directly to the array of LEDs in the form of an encapsulant. Alternatively the photoluminescence component is a separate component and remote to the array of LEDs such as tubular component that surrounds the LEDs.