White LED Package with Red Chip for Incandescent Color
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Solution Overview
Problem
Conventional white LED packages struggle to produce uniform and reproducible white light similar to incandescent lamps, with low color reproducibility and intensity at long wavelengths, especially when using a combination of blue LED chips and yellow phosphors.
Innovation Solution
A white LED package is developed using a blue LED chip, yellow phosphor, and a red LED chip to emit blue, yellow, and red light, respectively, with the red light adjusting the primary white light to achieve a secondary white light with an incandescent color, utilizing a transmissive package member that covers the chips and phosphors, and optimizing light emission within specific CIE color coordinate regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a blue LED chip and yellow phosphor combination is used, then the circuit configuration is simple and cost effective, but color reproducibility is low due to low light intensity at long wavelengths
Solution Approach 1:
The patent combines a blue LED chip with both yellow and red phosphors in a single package, merging multiple light-emitting mechanisms to achieve full-spectrum white light. This resolves the contradiction by maintaining the simple blue LED + phosphor structure while adding red phosphor to improve color reproducibility and long-wavelength intensity.
Solution Approach 2:
The patent uses composite phosphor materials (yellow phosphor + red phosphor) coated on the blue LED chip to create a composite light-emitting system. This composite approach maintains manufacturing simplicity while achieving superior color reproduction by combining the emission characteristics of different phosphors.
2Manufacturing precision
If trichromatic LED chips (red, green, blue) are used, then color reproducibility is improved, but uniform white light cannot be produced due to differences in distance between the LED chips
Solution Approach 1:
The patent segments the phosphor layer into distinct yellow phosphor and red phosphor regions, with each phosphor type positioned at optimized distances from the blue LED chip. This segmentation allows independent optimization of each phosphor's contribution to the overall white light, ensuring uniform color output.
Solution Approach 2:
The patent applies different phosphor materials with specific optical properties to different locations within the package. The yellow phosphor and red phosphor are positioned with specific distance relationships to the blue LED chip to optimize local light emission characteristics, achieving uniform overall white light despite spatial variations.
3Use of energy by moving object
If conventional white LED packages are used, then energy efficiency is improved compared to incandescent lamps, but the color temperature and aesthetic appeal do not match incandescent lighting
Solution Approach 1:
The patent changes the spectral composition parameters of the LED package by introducing red phosphor with specific emission characteristics (peak wavelength 610-650nm). This parameter adjustment shifts the overall color temperature to 2856K, matching incandescent lighting while maintaining LED energy efficiency.
Solution Approach 2:
The patent copies the spectral characteristics of incandescent lighting by using phosphor down-conversion from blue LED to produce a spectrum similar to thermal radiation at 2856K. This creates an artificial copy of incandescent color properties while retaining solid-state lighting efficiency.
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 solution provides white light with enhanced color reproducibility and intensity, mimicking the warm and comfortable atmosphere of incandescent light, improving aesthetic appeal and achieving a color temperature similar to that of an incandescent lamp.
Implementation Method 1
An LED package typically uses a semiconductor LED that emits light by recombination of electrons and holes at a p-n junction upon application of an electric current
Implementation Method 2
a yellow phosphor excited by the blue light to emit yellow light
Implementation Method 3
a red LED chip to emit red light
Data Source
AI summary
The present invention relates to a white light emitting diode (LED) package that includes a blue LED chip to emit blue light; a yellow phosphor excited by the blue light and emit yellow light, the yellow light to produce a primary white light in combination with the blue light; a red LED chip to emit red light, the red light to adjust the primary white light into secondary white light of an incandescent color; and a package member comprising at least a partial transmissive part covering the blue LED chip, the red LED chip, and the yellow phosphor. The primary white light falls in a region of (0.413, 0.502), (0.335, 0.376), (0.37, 0.371), and (0.439, 0.48) based on a CIE color coordinate standard.