Thin Color Converting Layers for LED Illumination Modules
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Solution Overview
Problem
Current LED-based illumination devices face limitations in light output level, color quality due to color point instability, poor color rendering, and spatial/angular variations, and are expensive due to the need for color control electronics and sensors.
Innovation Solution
The use of a reflective and transmissive color converting element with a PTFE layer and phosphor particles embedded in a polymer matrix, where the thickness of the color converting layer is less than five times the average diameter of the phosphor particles, to enhance light output and color consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED illumination devices are used, then the device structure is simple, but the light output level is limited and color quality is poor
Solution Approach 1:
The patent applies composite materials by combining phosphor particles with a polymer matrix to create a color converting layer. This composite structure enables the layer to convert LED light output while maintaining mechanical integrity, thereby improving light output level and color quality without requiring complex electronic control systems. The composite material approach allows the color converting layer to function as both an optical element and a structural component.
Solution Approach 2:
The patent implements local quality by creating a color converting layer with specific local properties - the layer is positioned between the LED and the output, and its thickness is controlled to be greater than the average phosphor particle diameter. This localized optimization of the color converting layer enables improved light output and color rendering at the critical interface where light conversion occurs, without complicating the overall device structure.
2Stability of the object's composition
If conventional color converting layers are used, then the manufacturing process is simple, but color point stability is poor
Solution Approach 1:
The patent applies parameter changes by controlling the thickness of the color converting layer to be greater than the average phosphor particle diameter. This specific thickness parameter ensures that the layer is sufficiently thick to provide stable color conversion while remaining manufacturable. The parameter optimization balances color point stability with ease of manufacture, as the thickness control can be achieved through standard coating processes without requiring complex manufacturing steps.
Solution Approach 2:
The patent implements local quality by ensuring uniform distribution of phosphor particles throughout the polymer matrix in the color converting layer. This local uniformity in material composition and particle distribution ensures consistent color point stability across the entire layer, while the overall manufacturing process remains simple and compatible with conventional coating techniques.
3Illumination intensity
If conventional LED illumination devices are used, then the device structure is simple, but color rendering is poor
Solution Approach 1:
The patent uses composite materials by incorporating phosphor particles into a polymer matrix to create a color converting layer. This composite structure enables effective wavelength conversion that improves color rendering, as the phosphor particles can be selected to emit at specific wavelengths that fill spectral gaps. The composite material approach achieves better color rendering without adding complex electronic control systems or sensors.
Solution Approach 2:
The patent applies the extraction principle by removing the need for complex color control electronics and sensors from the device structure. Instead, the color rendering improvement is achieved through the optical properties of the phosphor-polymer composite layer, which passively converts LED light to produce better color quality. This extracts the color control function from active electronic components and transfers it to a passive optical material.
4Stability of the object's composition
If conventional LED illumination devices are used, then the device structure is simple, but spatial and angular color variations occur
Solution Approach 1:
The patent implements local quality by ensuring uniform phosphor particle distribution and consistent layer thickness throughout the color converting layer. This local uniformity in material properties ensures that color conversion is consistent across different spatial locations and viewing angles, eliminating color variations without requiring complex optical elements or alignment mechanisms.
Solution Approach 2:
The patent uses composite materials where phosphor particles are uniformly dispersed in a polymer matrix, creating a homogeneous color converting layer. This composite structure ensures consistent optical properties throughout the layer, which maintains color consistency across different viewing angles and positions, thereby improving color stability without adding device complexity.
5Stability of the object's composition
If color control electronics and sensors are added to maintain color point, then color quality is improved, but device cost increases
Solution Approach 1:
The patent extracts the color control function from active electronic components (electronics and sensors) and transfers it to a passive optical material - the phosphor-polymer composite layer. This eliminates the need for expensive color control electronics and sensors while maintaining color point stability through the inherent optical properties of the composite material.
Solution Approach 2:
The patent replaces expensive, complex color control electronics with a simpler, more cost-effective phosphor-polymer composite layer. The composite material provides passive, reliable color conversion without requiring expensive electronic components, sensors, or complex control systems, thereby significantly reducing device cost while maintaining color quality.
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 solution improves luminous output and color consistency, reducing the need for expensive color control electronics and sensors, while maintaining durability and efficiency in heat management.
Implementation Method 1
The color converting layer includes phosphor particles embedded in a polymer matrix
Implementation Method 2
The homogeneous suspension is applied to a surface to form an uncured color converting layer, which is heated to vaporize the solvent
Data Source
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AI summary
An illumination module includes a plurality of Light Emitting Diodes (LEDs). The illumination module may include a reflective color converting element with a PTFE layer and a color converting layer fixed to the PTFE layer. The color converting layer includes phosphor particles embedded in a polymer matrix and has a thickness that is less than five times an average diameter of the phosphor particles. The illumination module may include a transmissive color converting element. The color converting elements may be produced by mixing a polymer binder with a solvent and phosphor particles to form a homogeneous suspension of the phosphor particles. The homogeneous suspension is applied to a surface to form an uncured color converting layer, which is heated to vaporize the solvent. The cured color converting layer includes the phosphor particles suspended in the polymer binder