Phosphor Layer Air Gap for LED Color Consistency
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Solution Overview
Problem
Semiconductor light emitting devices with phosphor layers face inconsistencies in color temperature and color rendering index due to variations in phosphor particle distribution and thickness, leading to increased manufacturing costs from the binning process.
Innovation Solution
A light emitting device design that includes a light emitting semiconductor within an encapsulation layer, a phosphor layer provided over the encapsulation layer, and an air gap between them, with the phosphor layer manufactured separately to control particle distribution and thickness, allowing for pre-determination of optical characteristics before incorporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the phosphor layer is filled into the LED cavity during manufacturing, then the light emitting device can be assembled, but the phosphor particle distribution and thickness vary, resulting in inconsistent color temperature and color rendering index
Solution Approach 1:
The phosphor layer is separated from the LED cavity filling process. Instead of filling phosphor-silicone mixture into the cavity during LED assembly, the phosphor layer is manufactured as a separate component with controlled particle distribution, then applied to the encapsulation layer afterward. This segmentation allows independent optimization of phosphor layer uniformity without affecting LED assembly simplicity.
Solution Approach 2:
The phosphor layer is manufactured and pre-tested for optical characteristics before being applied to the LED device. This preliminary action ensures that the phosphor layer achieves desired uniformity and consistency in color temperature and color rendering index before integration, allowing for quality control without complicating the final assembly process.
2Ease of manufacture
If the phosphor layer is filled into the LED cavity during manufacturing, then the device can be assembled, but the variations in phosphor particle distribution and thickness require binning, increasing manufacturing cost
Solution Approach 1:
By dividing the manufacturing process into separate steps - LED assembly without phosphor, then separate phosphor layer manufacturing and application - the system eliminates the need for binning. The phosphor layer can be precisely controlled and applied consistently, ensuring uniform optical characteristics across all devices without requiring post-manufacturing sorting.
Solution Approach 2:
The phosphor layer is manufactured and quality-tested in advance before application to the LED device. This preliminary quality assurance ensures that every device receives a phosphor layer with consistent optical properties, eliminating variability that would otherwise require binning and reducing overall device complexity.
3Manufacturing precision
If the phosphor layer is manufactured separately with controlled particle distribution, then consistent optical characteristics are achieved, but the manufacturing process becomes more complex
Solution Approach 1:
The manufacturing process is segmented into independent modules: LED assembly, phosphor layer manufacturing, and phosphor layer application. This segmentation allows each module to be optimized independently - the phosphor layer can achieve precise particle distribution control in its dedicated manufacturing process without adding complexity to the LED assembly process itself.
Solution Approach 2:
The phosphor layer is manufactured and pre-quality-controlled as a separate component before application. This preliminary manufacturing with controlled particle distribution ensures high precision in optical characteristics while containing the complexity within a dedicated process, rather than attempting to control everything within a single integrated assembly process.
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 ensures consistent optical characteristics of the light emitting device, eliminating the need for binning and reducing manufacturing costs by allowing for the selection and predetermination of phosphor and semiconductor characteristics before assembly.
Implementation Method 1
a phosphor layer that converts a portion of the blue light to yellow light
Data Source
AI summary
A light emitting device and method of producing the same is disclosed. The light emitting device includes a light emitting semiconductor, an encapsulation layer, wherein the light emitting semiconductor is disposed within the encapsulation layer, a phosphor layer provided over the encapsulation layer, and an air gap provided between the encapsulation layer and the phosphor layer.