Stacked LED Module with Phosphor Layer for High Color Saturation
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Solution Overview
Problem
Current white light emitting diode (LED) technologies face challenges in achieving high color saturation, efficient light mixing, and cost-effective manufacturing, particularly due to complex wire bonding processes and varying chip lifespans, leading to suboptimal chromaticity and high manufacturing costs.
Innovation Solution
A white light emitting diode module comprising a conducting wire frame, a first primary color chip, and a second primary color chip with a phosphor layer, where the chips are stacked and the phosphor layer is excited to produce fluorescent light, optimizing light emitting surface areas and wavelengths to achieve high color saturation and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If three chips (RGB) are packaged into an LED set to produce white light, then the color gamut and mixing light efficiency are improved, but the manufacturing cost increases and the control of light proportion becomes difficult
Solution Approach 1:
The patent divides the white light generation into two separate modules: a blue LED chip for generating blue light and a yellow phosphor layer for converting to yellow light. This segmentation allows independent optimization of each component, simplifying the manufacturing process while maintaining good color mixing effects.
Solution Approach 2:
The patent extracts the red light generation function from the three-chip system by using a yellow phosphor layer that converts blue light to yellow light, which when mixed with the remaining blue light produces a perception of red component. This extraction simplifies the structure from three chips to one chip plus phosphor layer.
2Ease of manufacture
If a blue LED is used to excite yellow phosphor to produce white light, then the manufacturing cost is reduced, but the chromaticity of the produced white light is poor
Solution Approach 1:
The patent applies local quality by using a specifically formulated yellow phosphor layer with controlled particle size distribution and concentration. The phosphor layer is applied locally on the blue LED chip with optimized thickness and coverage, creating localized light conversion zones that enhance the overall chromaticity while maintaining manufacturing simplicity.
Solution Approach 2:
The patent uses composite materials by combining blue LED semiconductor material with yellow phosphor materials (such as Y3Al5O12:Ce or Lu3Al5O12:Ce) in a layered structure. This composite approach allows the blue LED to provide efficient excitation while the yellow phosphor converts part of the blue light to yellow, creating a white light with improved chromaticity compared to simple phosphor conversion.
3Illumination intensity
If the light emitting surface areas of the first and second primary color chips are optimized with a specific area ratio, then the color saturation is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the area ratio parameter of the two primary color chips to fall within a specific range (0.5≤A1/A2≤2). This parameter optimization ensures that the blue and green light emissions are balanced, allowing the yellow phosphor conversion to produce high color saturation white light. The area ratio is controlled during the chip mounting process through standardized procedures.
Solution Approach 2:
The patent allows a relatively wide area ratio range (0.5 to 2) rather than requiring a precise single value. This partial optimization approach ensures that even with variations in chip size or mounting position, the system maintains good color saturation performance, reducing the stringency of manufacturing precision requirements while still achieving the desired optical performance.
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 module achieves up to 98% color saturation and a light emitting efficiency of 55-60 lm/W, making it suitable for various illumination applications while reducing manufacturing complexity and costs.
Implementation Method 1
The phosphor layer is formed on the second primary color chip and excited to produce a fluorescent light with a wavelength λ3, and 600 nm≦λ3≦670 nm
Data Source
AI summary
Disclosed is a white light emitting diode module including a conducting wire frame, a first primary color chip, a second primary color chip and a phosphor layer. The conducting wire frame has an accommodating groove. The first primary color chip is installed at the bottom of the middle of the accommodating groove, and the first primary color chip transmits a first light emitting source with a wavelength λ1. The second primary color chip is stacked on top of the first primary color chip and the second primary color chip transmits a second light emitting source with a wavelength λ2. The phosphor layer is formed on the second primary color chip and excited to produce a fluorescent light with a wavelength λ3. Therefore, the stacked LED chips and the phosphor can be used to obtain a white light source with high color saturation.