The core reasons for the decline in LED brightness are material aging, insufficient heat dissipation, or circuit losses, which are normal physical phenomena.
1. Material Aging Leading to Luminous Decay: After prolonged use, the phosphors and semiconductor materials inside the LED chip gradually age, causing the luminous efficiency to decrease at a rate of 3%-5% per year. LEDs with high color temperatures (above 6000K) contain more high-energy blue light components, resulting in a faster rate of decay.
2. Degradation of Heat Dissipation System Performance: Aging of the aluminum alloy heat sink substrate and thermally conductive adhesive reduces heat conduction efficiency. When the junction temperature exceeds 150℃, every 10℃ increase accelerates the brightness decay rate by 30%. In summer, the temperature inside a sealed lampshade can reach 80℃, making heat accumulation more likely.
3. Driver Power Supply Losses: The evaporation of electrolyte in inferior capacitors at high temperatures causes output voltage fluctuations. When the supply current is below 70% of the rated value, the LED can continue to operate, but the brightness will be significantly reduced, and there is a risk of flickering.
After 20,000 hours of use, ordinary LED lights typically retain around 70% of their brightness, meeting national standards. However, in humid kitchen or bathroom environments, the oxidation rate of the LED chip solder joints increases threefold, causing a premature decrease in brightness even before the theoretical lifespan is reached. Regularly cleaning dust from light fixtures and ensuring proper ventilation can reduce the rate of brightness decay by more than 40%.
