Side-View White LED Package Design for Parallel Light Output
Solution Overview
Problem
Side-view surface mount white light emitting diodes (LEDs) experience reduced visible output due to inefficiencies in light distribution and phosphor performance, leading to suboptimal brightness in display applications.
Innovation Solution
The use of non-agglomerated phosphor particles with specific size ranges and inorganic coatings, combined with wide bandgap semiconductor chips and optimized encapsulant and package designs, enhances light extraction and color uniformity, directing output parallel to the display plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional phosphor particles are used in side-view surface mount LEDs, then the device structure is simple, but the visible light output is reduced due to agglomeration and poor light extraction
Solution Approach 1:
The patent applies parameter changes by controlling phosphor particle size within a specific range (0.1-10 micrometers) and applying inorganic coatings to particle surfaces. These parameter modifications prevent agglomeration, improve light extraction efficiency, and enhance visible output without fundamentally changing the device structure or requiring complex additional components.
Solution Approach 2:
The patent uses composite materials by combining phosphor particles with inorganic coatings (such as silica or alumina) to create enhanced phosphor materials. These coated particles provide both the light-emitting properties of phosphor and the anti-agglomeration, light-extraction benefits of the inorganic coating layer, resolving the contradiction between simplicity and performance.
2Manufacturing precision
If phosphor particles are used without size control, then manufacturing is simpler, but color uniformity and light extraction are compromised
Solution Approach 1:
The patent specifies a controlled particle size range (0.1-10 micrometers) to optimize both color uniformity and light extraction. This parameter control achieves consistent optical properties across the phosphor layer while remaining compatible with standard manufacturing processes through techniques like ball milling and classification.
Solution Approach 2:
The inorganic coating acts as an intermediary between the phosphor core and the surrounding encapsulant environment. This coating layer prevents particle agglomeration, controls light extraction, and maintains color uniformity, while the overall manufacturing process remains relatively simple and compatible with existing LED production lines.
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 configuration improves the luminous intensity and color rendering of side-view LEDs, achieving higher brightness and uniformity in display applications while maintaining simplicity in construction and circuitry.
Implementation Method 1
a light emitting diode that emits in a higher energy portion of the visible spectrum (i.e., blue, violet, or ultraviolet) is used in conjunction with a phosphor that emits in a lower energy region of the visible spectrum
Implementation Method 2
non-agglomerated phosphor particles with specific size ranges and inorganic coatings, combined with wide bandgap semiconductor chips and optimized encapsulant and package designs, enhances light extraction
Implementation Method 3
The basic physics of light emitting diodes is well understood in the art
Data Source
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AI summary
A light emitting diode is disclosed. The diode includes a package support and a semiconductor chip on the package support, with the chip including an active region that emits light in the visible portion of the spectrum. Metal contacts are in electrical communication with the chip on the package. A substantially transparent encapsulant covers the chip in the package. A phosphor in the encapsulant emits a frequency in the visible spectrum different from the frequency emitted by the chip and in response to the wavelength emitted by the chip. A display element is also disclosed that combines the light emitting diode and a planar display element. The combination includes a substantially planar display element with the light emitting diode positioned on the perimeter of the display element and with the package support directing the output of the diode substantially parallel to the plane of the display element.