LED Module Ceramic Case Pad Positioning
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Solution Overview
Problem
Conventional LED modules experience a reduction in light emission over time due to corrosion of silver (Ag) surfaces in the wiring pattern, which absorbs light emitted by the LED chip.
Innovation Solution
The LED module is designed with a ceramic case and pads made of Ag or Au, where the pads are positioned inward of the LED unit, and a reflector with recesses to accommodate bonding pads, along with a light-transmitting portion containing a fluorescent substance to enhance light emission and prevent absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Ag is used for the wiring pattern to ensure good electrical conductivity, then electrical performance is improved, but the Ag surface corrodes and darkens over time, causing light absorption and reduced light emission
Solution Approach 1:
The patent uses a sacrificial Ag layer that is intentionally designed to be replaceable. The Ag pad is positioned inward of the LED unit edge, creating a non-light-emitting zone where Ag can corrode without affecting light output. This sacrificial layer protects the main wiring pattern while accepting degradation, effectively isolating the conductivity function from the light emission function.
Solution Approach 2:
The wiring pattern is segmented into functional zones: Ag pads positioned inward of the LED unit edge for electrical connection, and bonding pads positioned outward for light-emitting connections. This segmentation separates the conductivity-critical Ag region from the light-emission-critical bonding pad region, allowing Ag to corrode without impacting light output.
2Illumination intensity
If the pad outer edge is positioned at or beyond the LED unit outer edge to maximize light emission area, then light output is improved, but the pad material absorbs light when corroded, reducing light emission
Solution Approach 1:
The harmful Ag pad is extracted from the light-emitting zone and repositioned inward of the LED unit edge. This creates a dedicated non-light-emitting zone where Ag corrosion occurs without interfering with light output. The light-emitting zone is thus purified of light-absorbing elements, maintaining high illumination intensity.
Solution Approach 2:
The pad positioning problem is solved by changing the spatial dimension: instead of extending pads to the LED unit edge in the light-emitting plane, the Ag pad is recessed inward, creating a stepped or zoned structure. This dimensional change separates the electrical connection function from the light emission function in space.
3Illumination intensity
If a light-transmitting portion is added to cover the LED chip to protect and transmit light, then light transmission is improved, but it does not address the root cause of light absorption by corroded wiring pattern materials
Solution Approach 1:
The Ag pad is pre-positioned inward of the LED unit edge before operation, creating a preventive non-light-emitting zone. This preliminary spatial arrangement prevents the future problem of light absorption by corroded Ag, addressing the root cause rather than just treating the symptom with a light-transmitting cover.
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 suppresses the reduction in light emission over time, maintaining high brightness and efficiently dissipating heat, while the ceramic material and reflector arrangement prevent light leakage and enhance brightness.
Implementation Method 1
the fluorescent substance is configured to be excited by the light from the LED unit, thereby emitting light of a wavelength different from that of the light from the LED unit
Implementation Method 2
at least one LED unit including an LED chip; The LED chip 94 is the light source of the LED module X and emits light of a predetermined wavelength
Implementation Method 3
The LED unit and the pad are bonded to each other by eutectic bonding
Data Source
AI summary
An LED module according to the present invention includes an LED unit 2 and a case 1, where the LED unit includes an LED chip 21, and the case 1 includes a main body 11 made of a ceramic material and a pad 12a on which the LED unit 2 is mounted. The outer edge 121a of the pad 12a is positioned inward of the outer edge 2a of the LED unit 2 as viewed in plan. These arrangements prevent the light emission amount of the LED module A1 from reducing with time.