Substrateless LED Package with Light-Shielding Layer for Finer Pitch
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Solution Overview
Problem
Current light emitting diode (LED) packages face challenges in achieving finer pitch due to size limitations, leading to chromatic aberration and increased costs, particularly with surface mount devices and chip on board techniques, which also complicate inspection and repair.
Innovation Solution
A light emitting diode package design featuring a circuit layer thinner than 100 micrometers, a light-shielding layer with apertures, and an encapsulation layer with a refractive index of 1.4 to 1.7 and Young's modulus greater than 1 GPa, allowing for the placement of LEDs in apertures and encapsulation without a substrate, enabling improved display quality and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If surface mount devices technique is used, then LED can be mounted on circuit substrate, but package size limits make it hard to achieve finer pitch
Solution Approach 1:
The patent extracts the LED chip from the traditional substrate mounting approach and directly bonds it to the circuit board, eliminating the separate package substrate. This extraction allows finer pitch by removing the package size constraint while maintaining electrical connection functionality.
Solution Approach 2:
The patent implements a nested structure where the LED chip is directly integrated into the circuit board substrate, with the bonding pad embedded within the substrate structure. This nesting eliminates intermediate layers and reduces overall package size, enabling finer pitch.
2Reliability
If LED is installed on circuit substrate, then electrical connection is established, but chromatic aberration occurs from different viewing angle
Solution Approach 1:
The patent applies local quality by creating a recessed mounting area for the LED chip that is smaller than the overall package size. This localized structural modification controls light emission direction and reduces chromatic aberration from different viewing angles while maintaining electrical connection reliability.
Solution Approach 2:
The patent transitions from a planar mounting approach to a three-dimensional recessed structure. By utilizing vertical depth in addition to horizontal positioning, the LED chip is positioned at a controlled depth below the package surface, which optimizes light emission characteristics and reduces chromatic aberration.
3Reliability
If chip on board technique is used, then LED chip is encapsulated on circuit substrate, but inspection and repair become difficult
Solution Approach 1:
The patent applies partial encapsulation where the LED chip is surrounded by encapsulant material but the package structure includes accessible edges and surfaces. This partial approach provides sufficient environmental protection and mechanical support while maintaining accessibility for inspection and repair operations.
4Reliability
If traditional packaging is used, then LED is protected, but manufacturing costs increase and yield decreases
Solution Approach 1:
The patent merges the LED chip mounting, electrical connection, and encapsulation functions into a single integrated process step. The LED chip is directly bonded to the circuit board and encapsulated in one operation, eliminating separate processing steps and reducing manufacturing cost while improving yield.
Solution Approach 2:
The circuit board substrate serves multiple functions simultaneously: it provides mechanical support, electrical connection through bonding pads, and encapsulation housing. This multi-functionality reduces the number of separate components and assembly steps, lowering manufacturing cost and improving yield.
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 proposed design enhances display quality by reducing chromatic aberration and lowering manufacturing costs through increased yield and reliability, while allowing for substrateless packaging and improved LED placement, resulting in more efficient and cost-effective LED packages.
Implementation Method 1
A refractive index of the encapsulation layer is 1.4 to 1.7
Data Source
AI summary
A light emitting diode package including a circuit layer, a light-shielding layer, a plurality of light emitting diodes and an encapsulation layer is provided. A thickness of the circuit layer is less than 100 μm. The light-shielding layer is disposed on a first surface of the circuit layer and the light-shielding layer has a plurality of apertures. The light emitting diodes are disposed on the first surface of the circuit layer and in the apertures of the light-shielding layer. The light emitting diodes are electrically connected to the circuit layer. The encapsulation layer covers the light-shielding layer. A refractive index of the encapsulation layer is 1.4 and to 1.7. The Young's modulus of the encapsulation layer is larger than or equal to 1 GPa. A thickness of the encapsulation layer is greater than thicknesses of the light emitting diodes.