Warm White LED-Phosphor Layout for High CRI Light Output
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Solution Overview
Problem
Conventional white light emitting apparatuses using LEDs struggle to provide uniform warm white light with excellent color rendering properties due to complex circuit configurations and inefficiencies, particularly when using multiple primary colors or phosphor combinations, which often result in degraded color rendering and light intensity issues.
Innovation Solution
A warm white light emitting apparatus employing two LED-phosphor combinations, one generating base light of yellowish white and the other adjusting the Color Rendering Index (CRI), utilizing AC and DC LEDs with specific phosphor combinations to achieve a color temperature of 2500 to 4500K, and incorporating a partition wall to separate the phosphor combinations and reduce light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If three primary color LEDs (red, green, blue) are used to generate white light, then color rendering property is improved, but circuit configuration becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent combines multiple LEDs of the same color (blue or UV) with different phosphors into a single integrated structure. Instead of using separate red, green, and blue LED circuits, the invention merges the light generation function into one or more LED-phosphor combinations where phosphors convert LED light to achieve the desired spectral output, thereby simplifying the circuit configuration while maintaining good color rendering properties.
2Device complexity
If blue LED with yellow phosphor is used, then circuit configuration is simplified and manufacturing cost is reduced, but color rendering property and color reproduction property are degraded
Solution Approach 1:
The patent uses composite phosphor materials with different characteristics (yellow phosphor with peak wavelength 560-580nm and red phosphor with peak wavelength 610-650nm) combined with blue or UV LEDs. This composite approach creates a multi-peaked emission spectrum that maintains the simplicity of the blue LED+phosphor structure while significantly improving color rendering properties through the complementary spectral contributions of different phosphors.
3Device complexity
If multiple phosphors are positioned in encapsulant without separation, then device structure is simplified, but light loss increases and phosphor efficiency is degraded
Solution Approach 1:
The patent segments the phosphor arrangement by providing separate accommodating spaces for different phosphors within the housing. The first phosphor and second phosphor are positioned in distinct regions with their respective LEDs, allowing independent optimization of each phosphor's excitation and emission characteristics. This segmentation prevents harmful optical interactions between different phosphors while maintaining a relatively simple integrated structure.
4Manufacturing precision
If blue LED with red and green phosphors is used, then color rendering property is improved, but light loss increases due to different excitation wavelengths requiring separate positioning
Solution Approach 1:
The patent introduces a housing with specifically designed accommodating spaces that act as intermediaries between the LEDs and phosphors. These structured spaces optimize the optical path and spatial relationship between light sources and phosphor materials, enabling efficient energy transfer while preventing light loss. The housing structure mediates the interaction between multiple LED-phosphor combinations, allowing them to work together effectively without harmful interference.
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 enables the production of high-quality warm white light with improved color rendering near the black body locus curve, suitable for large-sized electronic displays, while minimizing flickering and total harmonic distortion through the use of AC and DC LEDs and additional circuit units.
Implementation Method 1
An LED includes a junction of p-type and n-type semiconductors, and uses a light emitting semiconductor in which energy corresponding to a bandgap of a semiconductor is emitted in the form of light due to a combination of electrons and holes when voltage is applied thereto
Implementation Method 2
A white light emitting apparatus that includes an LED-phosphor combination to generate a base light of white or yellowish white
Data Source
Figure 1~4
Figure 5~6
Figure 7~8(b)
AI summary
A warm white light emitting apparatus includes a first light emitting diode (LED)-phosphor combination to generate a base light that is white or yellowish white and a second LED-phosphor combination to generate a Color Rendering Index (CRI) adjusting light. The base light the CRI adjusting light together make a warm white light having a color temperature of 2500 to 4500K.