Dual Blue LED White Light Device for Blue Hazard Reduction
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Solution Overview
Problem
Conventional white light emitting devices do not effectively reduce blue light hazard (BLH) while maintaining high color rendering index (CRI) and correlated color temperature (CCT), which is essential for human-friendly lighting that considers human biorhythms and retinal safety.
Innovation Solution
A white light emitting device comprising a substrate with two blue LEDs emitting light at specific wavelengths (445-455 nm and 465-495 nm) and wavelength conversion materials that convert these blues into white light, with a combination of phosphors like (Sr,Ca)AlSiN3:Eu, CaAlSiN3:Eu, and KxSiFy:Mn4+, adjusting the intensity ratio to minimize BLH and maximize CRI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional single blue LED with phosphor is used to generate white light, then device complexity is low, but blue light hazard cannot be effectively reduced while maintaining high CRI and CCT
Solution Approach 1:
The patent divides the single blue LED into two separate blue LEDs with different peak wavelengths (445-455 nm and 465-495 nm). Each blue LED is paired with its own wavelength conversion materials, creating two independent light conversion paths that combine to form white light. This segmentation allows independent optimization of each path to reduce blue light hazard while maintaining high CRI and CCT.
Solution Approach 2:
The patent employs composite wavelength conversion materials including (Sr,Ca)AlSiN3:Eu, CaAlSiN3:Eu, and KxSiFy:Mn4+ phosphors in combination with the two blue LEDs. These composite materials enable precise control over the spectral output, allowing the device to achieve high CRI and CCT while minimizing blue light hazard through optimized material composition and ratios.
2Object-affected harmful factors
If multiple wavelength conversion materials are used to reduce blue light hazard, then blue light hazard is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise wavelength ranges for the two blue LEDs (445-455 nm and 465-495 nm) and corresponding peak emission ranges for the wavelength conversion materials. By defining these parameter ranges, the patent enables manufacturers to achieve consistent blue light hazard reduction and high CRI/CCT performance through controlled selection of materials within these specifications, balancing precision requirements with practical manufacturability.
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 device significantly reduces blue light hazard while maintaining high CRI and CCT, providing human-friendly lighting that optimizes biorhythms and reduces retinal damage, with adjustable intensity ratios to achieve desired spectral properties.
Implementation Method 1
a first light emitting diode disposed on the substrate, the first light emitting diode configured to emit first blue light having a peak intensity at a wavelength within the range of 445 nm to 455 nm
Implementation Method 2
a second light emitting diode disposed on the substrate, the second light emitting diode configured to emit second blue light having a peak intensity at a wavelength within the range of 465 nm to 495 nm
Implementation Method 3
a first wavelength conversion material configured to emit first light having a peak intensity at a wavelength within the range of 520 nm to 560 nm
Implementation Method 4
a second wavelength conversion material configured to emit second light having a peak intensity at a wavelength within the range of 600 nm to 645 nm
Data Source
AI summary
A white light emitting device includes a substrate, a first light emitting diode configured to emit first blue light having a peak intensity at a wavelength within the range of 445 nm to 455 nm, a second light emitting diode configured to emit second blue light having a peak intensity at a wavelength within the range of 465 nm to 495 nm, and a wavelength conversion unit configured to convert portions of the first blue light and the second blue light, and to provide white light formed by a combination of the converted portions of the first blue light and the second blue light with unconverted portions of the first blue light and the second blue light. The wavelength conversion unit includes a first wavelength conversion material configured to emit first light having a peak intensity at a wavelength within the range of 520 nm to 560 nm, and a second wavelength conversion material configured to emit second light having a peak intensity at a wavelength within the range of 600 nm to 645 nm.