Individually Controllable LED Packages for Uniform High-Density Arrays
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Solution Overview
Problem
Conventional LED array devices face challenges in achieving high-density arrays with small pixel pitches due to difficulties in preventing light overlap and non-illuminated zones, which affect resolution and homogeneity, and are limited by optical losses in reflective surfaces and internal reflection within LED packages.
Innovation Solution
The LED package includes individually controllable LED chips with electrical connections that reduce corrosion and forward voltage, and features a light-altering material like fused silica or titanium dioxide particles to enhance light extraction and directionality, along with a wavelength conversion element for adaptable emission patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED packages use reflective cups or metal reflectors to direct light, then light directionality is improved, but optical losses occur due to less than 100% reflectivity
Solution Approach 1:
The patent removes the metal reflector component entirely from the LED package. Instead of using a reflective cup or metal reflector to direct light, the invention relies on the intrinsic emission characteristics of the LED chip and optical design of the lens to achieve the desired light distribution, thereby eliminating optical losses associated with reflection.
Solution Approach 2:
The LED chip serves multiple functions: it generates light and its emission pattern inherently provides directionality without requiring a separate reflector component. The lens integrates both focusing and directional control functions, eliminating the need for additional optical components that would cause energy loss.
2Productivity
If LED chips are mounted in high-density arrays with small pixel pitches, then productivity and resolution are improved, but light overlap and non-illuminated zones occur affecting homogeneity
Solution Approach 1:
Each LED chip in the array is designed with a specific emission pattern optimized for its local position. The lens associated with each chip is tailored to direct light in a manner that fills gaps between adjacent chips, ensuring uniform overall illumination despite the high density arrangement. This local optimization of emission characteristics maintains homogeneity across the entire array.
Solution Approach 2:
The patent enables individual control of each LED chip within the array, allowing dynamic adjustment of emission patterns and intensities. This dynamic control compensates for variations in light distribution, preventing overlap and gaps by adaptively tuning each chip's contribution to the overall illumination pattern.
3Adaptability or versatility
If conventional LED packages use phosphor wavelength conversion, then color adaptability is improved, but some light is absorbed by the phosphor reducing efficiency
Solution Approach 1:
The patent introduces a fluorescent down-conversion layer as an intermediary between the blue LED chip and the final emitted light. This layer converts a portion of the blue light to other wavelengths, achieving wavelength diversity and color adaptability while maintaining high efficiency by using a transparent matrix material that minimizes absorption losses.
Solution Approach 2:
The wavelength conversion medium is formulated as a composite material combining fluorescent phosphors suspended in a transparent polymer or glass matrix. This composite structure enables efficient wavelength conversion while the transparent matrix minimizes light absorption, preserving overall luminous efficiency while achieving color adaptability.
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 enables high luminous intensity with controllable brightness and adaptable emission patterns, improving resolution and homogeneity in LED arrays for applications like automotive and aerospace lighting by reducing optical losses and enhancing light directionality.
Implementation Method 1
Light extraction and external quantum efficiency of an LED can be limited by a number of factors, including internal reflection. According to the well-understood implications of Snell's law, photons reaching the surface (interface) between an LED surface and the surrounding environment are either refracted or internally reflected.
Implementation Method 2
Light extraction and external quantum efficiency of an LED can be limited by a number of factors, including internal reflection. According to the well-understood implications of Snell's law, photons reaching the surface (interface) between an LED surface and the surrounding environment are either refracted or internally reflected.
Implementation Method 3
The reflective cup 14 may be filled with an encapsulant material 20, which may contain a wavelength conversion material such as a phosphor. At least some light emitted by the LED chip 12 at a first wavelength may be absorbed by the phosphor, which may responsively emit light at a second wavelength.
Data Source
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Figure 5A
AI summary
Solid-state light emitting devices including light-emitting diodes (LEDs), and more particularly packaged LEDs that include individually controllable LED chips are disclosed. In some embodiments, an LED package includes electrical connections configured to reduce corrosion of metals within the package; or decrease the overall forward voltage of the LED package; or provide an electrical path for electrostatic discharge (ESD) chips. In some embodiments, an LED package includes an array of LED chips, each of which is individually controllable such that individual LED chips or subgroups of LED chips may be selectively activated or deactivated. A single wavelength conversion element may be provided over the array of LED chips, or separate wavelength conversion elements may be provided over one or more individual LED chips of the array. Representative LED packages may be beneficial for applications where a high luminous intensity with a controllable brightness or adaptable emission pattern is desired.