LED Package Covering Wire Phosphor Reduces Light Attenuation
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Solution Overview
Problem
In surface-mounting LED packages, light emitted from the LED element is often absorbed by bonding wires, leading to a decrease in light intensity due to the absorption properties of metal materials like gold and copper, which have low reflectance for blue and ultraviolet light.
Innovation Solution
An LED package design that includes a covering layer with a phosphor that absorbs and converts the emitted light into wavelengths with lower absorbance in the bonding wires, such as using a red phosphor to convert blue light to red light, which has higher reflectance in gold wires, and a sealing resin with a second phosphor to emit light with longer wavelengths, reducing light attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal bonding wires (gold, copper) are used for electrical connection, then electrical conductivity is ensured, but light absorption increases leading to reduced light intensity
Solution Approach 1:
A covering layer containing phosphor particles is introduced as an intermediary substance between the metal bonding wire and the light path. This phosphor layer absorbs the blue light from the LED and converts it to yellow light, which has lower absorbance in the metal wire, thereby reducing overall light attenuation while maintaining electrical conductivity
Solution Approach 2:
The invention changes the wavelength parameter of the light by using phosphor to convert blue light (450-480nm) to yellow light (560-590nm). This wavelength transformation exploits the fact that metal bonding wires have lower absorbance in the yellow wavelength range compared to blue, thereby reducing light attenuation
2Use of energy by moving object
If blue LED is used for high efficiency, then energy efficiency is improved, but absorption by gold/copper wires increases due to low reflectance in blue wavelength range
Solution Approach 1:
The invention converts the harmful absorption effect of metal wires at blue wavelengths into a beneficial process by using phosphor to convert the blue light to yellow light. The yellow light then passes through the metal wire with minimal absorption, effectively converting the wire's high blue-light absorption into a non-issue while maintaining the energy efficiency of blue LEDs
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 design effectively minimizes light attenuation by converting blue light to red light, which is less absorbed by gold wires, and using a phosphor in the sealing resin to emit yellow light, resulting in improved light intensity and color rendering properties.
Implementation Method 1
a covering layer containing a phosphor and covering the bonding wire, wherein the phosphor is excited by emitted light from the LED element to emit light having an absorbance in the bonding wire lower than that of the emitted light and a wavelength longer than that of the emitted light
Implementation Method 2
a sealing resin which contains a second phosphor excited by the emitted light to emit second light
Data Source
AI summary
Provided is an LED package which is unlikely to cause the attenuation of emitted light from an LED element by bonding wires for electrical connection of the LED element. The LED package includes a board including a pair of connection electrodes formed thereon, an LED element mounted on the board, a bonding wire electrically connecting the LED element to the pair of connection electrodes, and a covering layer containing a phosphor and covering the bonding wire, wherein the phosphor is excited by emitted light from the LED element to emit light having an absorbance in the bonding wire lower than that of the emitted light and a wavelength longer than that of the emitted light.