The ratio of the luminous flux emitted by the light source to the power consumption is called the luminous efficiency, and the unit is lumens/watt. Different light sources emit the same luminous flux, and the less power they consume, the higher the luminous efficiency.
The higher the luminous efficiency value, the stronger the ability of the lighting equipment to convert electrical energy into light energy , that is, the stronger the energy saving of the lighting equipment under the condition of providing the same brightness; the better the lighting performance of the lighting equipment under the same power Stronger, that is, the greater the brightness.
Unit Lumens/W
Subject physical
Application field Mathematical Sciences
The light source of the total emitted light flux ratio of the electrical power (W) consumed by the light source, the light efficiency of the light source referred to.
The higher the luminous efficiency value, the stronger the ability of the lighting equipment to convert electrical energy into light energy , that is, the stronger the energy saving of the lighting equipment under the condition of providing the same brightness; the better the lighting performance of the lighting equipment under the same power Stronger, that is, the greater the brightness.
The original meaning of Luminous is brightness, and the measurement uses luminance, which means brightness, abbreviated as lm. The unit of luminous efficiency is brightness/watt, sometimes the transliteration ” lumen ” of Luminance is used as lumen/watt.
Light efficiency is also called the luminous efficiency of the light source or the power factor of the light source , which represents the ratio of the luminous flux emitted from the light source to the electric power consumed by the light source . That is, η=φ/E=φ/(φ+P)
Among them, η is the light efficiency, φ is the light energy radiated by the light source , E is the power of the light source, and P is the energy lost by the light source, mainly the heat.
The product samples or product manuals provided by various electric light source manufacturing companies contain the electric power and luminous flux values of various types and specifications of electric light sources, and the luminous efficiency can be obtained by using the above formula. Conversely, if you know the luminous efficiency and electric power of a certain electric light source, you can also calculate its luminous flux.
For example, the luminous flux of a 220V 2000W hard bromine tungsten lamp is 47000 lm and the luminous efficiency is 23.5 lm/W; while the luminous flux of a 220V 2000W steamed aluminum bulb is 35000 lm, and the luminous efficiency is 17.5 lm/W. The luminous efficiency of the former is much higher than that of the latter.
Luminous efficiency is an important symbol of the development of electric light sources. For more than 100 years, the lighting electric light source has made rapid development, whether it is the three historical stages of the development of thermal radiation light sources (vacuum bulb, filled bubble and halogen tungsten bulb), or the three historical stages of the development of the entire electric light source (incandescent lamp, fluorescent lamp) High-pressure mercury lamps and high-pressure sodium lamps), the luminous efficiency of new light sources have been greatly improved, laying a solid foundation for the development and development of modern lighting technology.