Phosphor Layer Thickness Control for LED Color Temperature
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Solution Overview
Problem
Existing light-emitting devices face challenges in controlling color temperature, leading to the disposal of white light-emitting packages that do not fall within a predefined range, resulting in inefficiencies and increased costs due to unnecessary phosphor deposition on units with deviating wavelengths.
Innovation Solution
A method involving the formation of light-emitting units on a substrate, measurement of light characteristics, and adjustable phosphor layer deposition using a printing method, specifically micro inkjet, to tailor phosphor thickness based on measured power and wavelength, ensuring optimal color temperature and reducing waste by omitting phosphor deposition on units outside the reference range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphor layer is deposited on all light-emitting units, then white light emission is achieved, but units with deviating wavelengths are wasted and costs increase
Solution Approach 1:
The patent applies local quality by depositing phosphor layers with different thicknesses on different light-emitting units based on their individual wavelength characteristics. Units with wavelengths closer to the reference range receive thicker phosphor layers, while units with deviating wavelengths receive thinner layers or no phosphor, thereby optimizing color temperature control and reducing material waste for each specific unit.
Solution Approach 2:
The patent changes the thickness parameter of the phosphor layer according to the measured wavelength characteristics of each light-emitting unit. By adjusting this physical parameter based on actual performance data, the system achieves optimal color temperature for each unit while minimizing phosphor material usage on units that cannot achieve the desired color temperature range.
2Manufacturing precision
If phosphor layer thickness is increased, then color temperature control is improved, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary measurement of wavelength characteristics for each light-emitting unit before phosphor deposition. This preliminary action allows the system to determine the optimal phosphor thickness for each unit in advance, enabling precise color temperature control while streamlining the manufacturing process by avoiding unnecessary trial-and-error adjustments.
Solution Approach 2:
The patent implements a feedback mechanism where the measured wavelength characteristics of each light-emitting unit inform the phosphor deposition process. This feedback loop ensures that the phosphor layer thickness is optimized for each unit's specific characteristics, achieving high manufacturing precision without requiring overly complex manufacturing systems.
3Productivity
If all units are processed uniformly, then manufacturing simplicity is maintained, but productivity decreases due to disposal of non-conforming units
Solution Approach 1:
The patent transitions from a static, uniform processing approach to a dynamic, adaptive process where phosphor deposition parameters are adjusted based on real-time measurement data. This dynamic approach increases productivity by reducing waste disposal while maintaining manufacturing simplicity through automated, data-driven decision-making.
Solution Approach 2:
The system performs self-service by automatically measuring wavelength characteristics and determining optimal phosphor deposition parameters for each unit without requiring manual intervention. This self-service capability enhances productivity by eliminating the need to dispose of non-conforming units while keeping the manufacturing process simple and automated.
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 allows for precise control of color temperature in light-emitting devices, reducing waste and costs by optimizing phosphor layer thickness according to measured light characteristics, thereby enhancing the manufacturing efficiency of light-emitting packages.
Implementation Method 1
depositing a yellow phosphor on a blue light element that generates blue light
Implementation Method 2
The phosphor layer, which is formed on the first light-emitting unit, is deposited to a thickness smaller than a reference thickness
Data Source
AI summary
Methods of fabricating of a light-emitting device are provided, the methods include forming a plurality of light-emitting units on a substrate, measuring light characteristics of the plurality of light-emitting units, respectively, depositing a phosphor layer on the plurality of light-emitting units using a printing method, and cutting the substrate to separate the plurality of light-emitting units into unit by unit. The phosphor layer is adjustably deposited according to the measured light characteristics of the plurality of light-emitting units.