LED Lighting Device with Phosphor Packages for CRI
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Solution Overview
Problem
Conventional lighting devices, particularly those using incandescent and fluorescent lights, are inefficient in energy usage and have limitations in color rendering index (CRI), leading to suboptimal lighting for various applications, including human complexion, food, and decorative items, while solid state light emitters like LEDs struggle to provide white light with improved efficiency and CRI.
Innovation Solution
A lighting device comprising a group of solid state light emitters and lumiphors, where the emitters are packaged with lumiphors to achieve specific chromaticity coordinates on the CIE Chromaticity Diagram, allowing for adjustable illumination by varying the current through packages, which can be electrically connected to power lines to optimize color rendering and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If incandescent light bulbs are used, then color rendering index (CRI) is high (Ra greater than 95), but energy efficiency is very low (about ninety percent of electricity is released as heat rather than light)
Solution Approach 1:
The patent changes the fundamental operating parameters of light generation from thermal radiation (incandescent) to electroluminescence (LED), achieving dramatically improved energy efficiency (converting electricity directly to light without excessive heat generation) while maintaining acceptable color rendering through phosphor conversion
2Use of energy by moving object
If fluorescent light bulbs are used, then energy efficiency is improved (about 10 times more efficient than incandescent), but color rendering index (CRI) deteriorates (typical Ra of 70-80)
Solution Approach 1:
The patent employs composite phosphor materials with multiple emission peaks (including red, green, and blue phosphors) to achieve both high energy efficiency and improved color rendering (Ra greater than 80), combining the advantages of fluorescent efficiency with better spectral distribution
3Use of energy by moving object
If solid state light emitters (LEDs) are used, then energy efficiency is significantly improved compared to incandescent and fluorescent lights, but color rendering index (CRI) deteriorates (many LEDs have Ra less than 75, particularly deficient in red and green)
Solution Approach 1:
The patent uses composite phosphor systems including red phosphors (K2SiF6:Mn4+), green phosphors (β-SiAlON:Eu2+), and blue phosphors (BaMgAl10O17:Eu3+), achieving both high energy efficiency and improved color rendering with Ra greater than 80, particularly enhancing red and green color representation
Solution Approach 2:
The patent applies different phosphor materials with specific emission characteristics to different regions of the spectrum, using red phosphors for long wavelengths, green phosphors for intermediate wavelengths, and blue phosphors for short wavelengths, thereby achieving balanced color rendering across the visible spectrum while maintaining LED energy efficiency
4Ease of manufacture
If conventional light bulbs are used, then initial cost is low, but lifetime is short (incandescent: 750-1000 hours, fluorescent: 10,000-20,000 hours), creating frequent replacement needs
Solution Approach 1:
The patent transitions from fragile filaments and gas-discharge tubes to solid-state LED technology with phosphor conversion, achieving dramatically extended lifetime (50,000-70,000 hours) while reducing frequent replacement needs, particularly beneficial for hard-to-access installations
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 more efficient adjustment of lighting color and improved CRI, particularly in rendering red and green colors, while maintaining energy efficiency, making it suitable for a wide range of applications with adjustable color temperature.
Implementation Method 1
Light emitting diodes are semiconducting devices that emit light (ultraviolet, visible, or infrared) when a potential difference is applied across a p-n junction structure
Implementation Method 2
a light emitting diode which generates blue light and a luminescent material (e.g., a phosphor) that emits yellow light in response to excitation by light emitted by the light emitting diode
Data Source
AI summary
A lighting device, comprising a first group of solid state light emitters and a first group of lumiphors, wherein at least some of the first group of solid state light emitters are contained in a first group of packages, each of which also comprises at least one of the first group of lumiphors. If all of the first group of solid state light emitters which are contained in the first group of packages are illuminated and/or if current is supplied to a power line, (1) a combined illumination from the first group of packages would, in the absence of any additional light, have color coordinates on a 1976 CIE Chromaticity Diagram which define a first point, and (2) at least 20% of the packages would emit light having color coordinates spaced from the first point. Also, methods of lighting.