Light-Emitting Diodes (LEDs) have revolutionized traditional lighting, with their outstanding luminous efficiency being the core advantage. As a key indicator of an LED’s ability to convert electrical energy into visible light, luminous efficiency directly determines lighting brightness, energy consumption, and environmental value, serving as the cornerstone for understanding LEDs’ energy-saving benefits.
I. What is LED Luminous Efficiency?
LED luminous efficiency is measured in lumens per watt (lm/W); a higher value indicates stronger energy utilization. Traditional incandescent bulbs only reach 10-20 lm/W, fluorescent lamps 50-80 lm/W, while mass-produced commercial LEDs have achieved 100-150 lm/W, with high-end products exceeding 200 lm/W, offering an energy-saving potential of over 50%. A comprehensive evaluation of luminous efficiency also requires referencing External Quantum Efficiency (EQE) and Wall-Plug Efficiency (WPE) to fully reflect lighting performance.
II. Key Factors Affecting LED Luminous Efficiency
LED luminous efficiency is influenced by multiple factors, with three core aspects:
1. Chip and Materials
The chip is the core of light emission. The crystal quality of mainstream Gallium Nitride (GaN)-based materials directly determines the upper limit of luminous efficiency, as defects cause energy loss. Additionally, chip size and quantum well structure also impact lighting efficiency.
2. Packaging and Optical Design
Packaging aims to reduce photon loss. High-refractive-index packaging glue and optimized structures can improve photon extraction rate. For white LEDs, phosphor performance is crucial—low-quality phosphors lead to rapid light decay and low luminous efficiency.
3. Heat Dissipation and Operating Environment
70%-80% of an LED’s electrical energy is converted into heat. Rising junction temperature significantly reduces luminous efficiency and accelerates aging, so effective heat dissipation design is key to maintaining high efficiency. Unstable operating current and voltage also affect luminous efficiency.
III. Technologies and Trends in Luminous Efficiency Improvement
LED luminous efficiency is approaching its theoretical limit of 250-300 lm/W. Improvement technologies focus on three areas: optimizing crystal quality and quantum well structure at the material level; adopting COB integrated packaging and nano-coating at the packaging level; and combining intelligent drivers to adjust working conditions for optimal efficiency. Future development will focus on the coordinated optimization of efficiency, light quality, and reliability, adapting to Mini/Micro LED technologies.
IV. Application Value of High-Luminous-Efficiency LEDs
The core value of high luminous efficiency lies in energy and cost savings. For municipal street lighting, high-efficiency LEDs can reduce power from 250W (traditional high-pressure sodium lamps) to below 100W, saving over 1,000 kWh per lamp annually. In home and commercial lighting, they cut electricity bills and maintenance costs. Moreover, they expand lighting scenarios to industrial, horticultural, and medical fields, driving green upgrades across industries.
Conclusion
The improvement of LED luminous efficiency is a result of the integration of semiconductor and lighting industries, serving as a vital support for global energy conservation and emission reduction. In the future, while maintaining high efficiency, LEDs will achieve comprehensive upgrades in light quality and intelligence, bringing more efficient, environmentally friendly lighting experiences.
