**Experimental Discussion on Improving the Temperature Resistance of LED Light Sources (II)**
**Introduction**
Semiconductor lighting has become one of the most significant technological revolutions of this century. Despite its rapid development, especially in high-power white LED technology, it still faces challenges such as light decay and heat dissipation. These inherent issues remain major obstacles to the widespread adoption of LED lighting. The problems of light degradation and thermal management are deeply embedded across the entire supply chain, from chip manufacturing to packaging, material selection, and final lamp design.
Currently, the industry lacks a clear understanding of what causes light decay, how to prevent it, and even basic theoretical consensus. This confusion leads to misguided approaches, with many companies copying each other without proper technical foundations, resulting in a chaotic environment. For years, efforts have focused on improving heat dissipation to reduce light decay, but the results have been minimal. As a result, solving LED light decay has become a central challenge in the industry.
This raises an important question: Why haven’t designers looked for solutions at the root cause of the problem? In this article, the author explores practical and theoretical methods to improve the temperature resistance of LED light sources, aiming to reduce light decay. A series of related articles and experimental reports will follow.
**Keywords**
LED light effect, LED thermal resistance, LED light decay, WFCOB light source, LED module lighting
**Table of Contents**
Chapter One
1. LED Light Effect: Understanding the difference between transient and steady-state light effects
2. LED Thermal Resistance: Distinguishing internal and external thermal resistance
3. LED Light Decay: Luminous flux reduction is not equal to light decay; irreversible damage defines true light decay
Chapter Two
4. Causes of LED Light Decay
5. Enhancing Temperature Resistance Reduces LED Light Decay
6. Why Improve Temperature Resistance of LED Light Sources?
7. How to Make LED Light Sources Withstand High Temperatures
Chapter Three
8. Aluminum Substrates Are Not Necessary for 3750V Withstand Voltage
9. Solving Drive Power Short Circuits
Chapter Four
10. Introducing the WFCOB Light Source
Chapter Five
11. Introducing LED Module Lighting
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**Chapter Two: The Cause of LED Light Decay**
1. **LED Light Decay is Irreversible Damage Due to Material Failure**
LED light decay refers to the permanent decrease in light output after prolonged operation. It is not simply a temporary drop in brightness due to temperature changes. Instead, it indicates that the light source has suffered irreversible damage, leading to a loss of luminous flux that cannot be restored. China currently lacks a standardized definition for LED light decay, though industry standards often consider a luminous flux maintenance rate of ≥70% after 5000 hours as acceptable.
2. **Reduction in Luminous Flux ≠Light Decay**
It is well known that when LEDs operate, their light intensity decreases as the junction temperature rises. However, this is a reversible phenomenon if the temperature returns to normal. True light decay occurs only when the LED suffers permanent damage, such as gel cracking or phosphor degradation. Therefore, any loss of initial light intensity that does not recover is considered real light decay.
3. **Main Cause of Light Decay: Poor Heat Resistance of the Gel**
Although the chip and phosphor can withstand high temperatures, the gel used in LED packaging is the main weak point. Most packaging materials can only resist up to 100°C, while high-power LEDs often reach over 200°C. Prolonged exposure to such temperatures causes the gel to crack, carbonize, or separate from the chip, leading to light decay.
From a luminaire system perspective, light decay is also influenced by thermal resistance, including heat dissipation channels, materials, and design. The performance of the LED light source depends on the quality of the chip, phosphor, gel, and packaging process. The key to reducing light decay lies in improving the temperature resistance of these components.
**Chapter Three: Enhancing Temperature Resistance to Reduce Light Decay**
1. **Why Improve Temperature Resistance of LED Light Sources?**
LEDs are semiconductor devices that generate relatively low heat. Under natural convection, their heat dissipation efficiency is limited. However, increasing the operating temperature of the heat sink can enhance heat dissipation. According to theory, radiative heat dissipation increases with the fourth power of temperature. Thus, higher temperatures lead to better cooling. By allowing LEDs to operate at higher temperatures safely, we can avoid light decay, reduce heat sink size, and increase current capacity, ultimately extending the lifespan of the LED.
2. **How to Make LED Light Sources Withstand High Temperatures?**
Various technologies have been explored, including flip-chip technology, phosphor separation, liquid cooling, COB packaging, and improved materials. While some show promise, they face challenges in cost, scalability, and long-term reliability. For example, flip-chip technology reduces thermal resistance but requires expensive ceramic substrates and complex processes. Phosphor separation improves heat dissipation but complicates optical alignment. Liquid cooling offers excellent thermal management but is difficult to implement in compact designs.
Despite these challenges, advancements in materials, packaging, and thermal management continue to push the boundaries of LED performance. The ultimate goal remains to develop a reliable, cost-effective solution that enhances temperature resistance and minimizes light decay.
**Conclusion**
LEDs are low-temperature semiconductor devices. Their heat dissipation efficiency is limited under natural conditions. Increasing the heat sink temperature allows more effective heat dissipation, reducing light decay and extending service life. This approach not only lowers costs but also improves performance, marking a significant advancement in LED technology.
**About the Author**
Wang Feng, born in 1941 in Tianjin, holds a university degree and is an engineer with over 40 years of experience in electronics and mechanical systems. He has worked as a technician, chief engineer, factory manager, and company executive. With extensive knowledge in LED system design and multiple invention patents, he brings strong technical expertise and project management skills to the field.
**Contact**
Phone: 13430533163
QQ: [Not Provided]
Website: http://news.chinawj.com.cn
Editor: Hardware Business Network Information Center
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