RGB LED and Phosphor Wavelength Conversion for High Color Rendering
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Solution Overview
Problem
Conventional LEDs with RGB emission methods struggle to achieve high color temperature and color rendering index due to varying luminous intensities of red, green, and blue light emitting diodes, limiting their application in lighting fixtures and displays.
Innovation Solution
Incorporating at least three light emitting diodes with different peak emission wavelengths and a wavelength-conversion means using phosphors to convert primary light into secondary light across a visible light spectrum, ensuring a high color temperature and color rendering index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the RGB emission method is used with three light emitting diodes, then white light can be generated, but the color rendering index remains low (60-70) and color temperature is limited due to varying luminous intensities of red, green, and blue LEDs
Solution Approach 1:
The patent introduces a wavelength conversion layer (phosphor) as an intermediary that converts blue light from a single LED into multiple wavelengths including yellow-green and red regions. This mediator approach simplifies the system from controlling three separate LEDs to controlling one LED with a wavelength conversion layer, while achieving improved color rendering index (Ra≥90) and adjustable color temperature (2000-10000K).
Solution Approach 2:
The patent changes the physical and chemical parameters of the wavelength conversion layer, specifically using phosphors with different peak emission wavelengths (560-580nm for yellow-green, 610-650nm for red) and adjusting their thickness and composition ratios. These parameter changes enable precise control over the spectral output, achieving high color rendering index and adjustable color temperature without increasing device complexity.
2Illumination intensity
If red, green, and blue light emitting diodes are used with different wavelengths, then white light can be realized, but the luminous intensities vary significantly making accurate color reproduction difficult
Solution Approach 1:
The patent extracts the wavelength conversion function from the LED structure itself and places it in a separate wavelength conversion layer. By using a blue LED (430-470nm) combined with phosphors that convert to yellow-green (560-580nm) and red (610-650nm) wavelengths, the system achieves uniform luminous intensity across the spectrum without relying on multiple LEDs with inherently different intensities, thereby improving both luminous intensity uniformity and color accuracy.
3Device complexity
If a single phosphor is used for wavelength conversion, then the structure is simplified, but the color rendering index and color temperature control are limited
Solution Approach 1:
The patent employs composite phosphor materials consisting of multiple phosphor types with complementary emission characteristics. Specifically, it combines phosphors emitting in the yellow-green region (560-580nm) with phosphors emitting in the red region (610-650nm). This composite approach enables precise control over the spectral power distribution, achieving high color rendering index (Ra≥90) and adjustable color temperature (2000-10000K) while maintaining relatively simple device structure.
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 enables LEDs with a color temperature of 2,000 to 10,000 K and a color rendering index of 90 or more, allowing for accurate reproduction of colors in the visible light range, suitable for home appliances, displays, and automotive lighting.
Implementation Method 1
a wavelength-conversion means to convert the primary light into secondary light in a visible light wavelength range
Implementation Method 2
the wavelength-conversion means includes any one selected from among a first phosphor having a peak emission wavelength between 450 and 520 nm, a second phosphor having a peak emission wavelength between 500 and 570 nm, a third phosphor having a peak emission wavelength between 570 and 680 nm
Data Source
AI summary
Disclosed herein is a light emitting device including at least three light emitting diodes having different peak emission wavelengths to primarily emit light in a blue, green or red wavelength range, and a wavelength-conversion means to convert primary light into secondary light in a visible light wavelength range. The light emitting device of the current invention has a high color temperature of 2,000 to 8,000 K or 10,000 K and a high color rendering index of 90 or more, and emits yellow-green light or orange light having a wide emission wavelength range. Since the light emitting device having high color temperature and excellent color rendering properties can easily realize desired emission on the color coordinate system, it is applicable to mobile phones, notebook computers, and keypads or backlight units for various electronic products, and in particular, automobiles and exterior and interior lighting fixtures.