1. The color temperature of some common light sources L […]
1. The color temperature of some common light sources
LED light sources can be roughly divided into three categories: warm white, neutral white and cool white. The discharge radiation of the traditional street light source, the sodium lamp, is concentrated in the two double-D spectral lines of 589.0 nanometers and 589.6 nanometers, so the color temperature is generally warm white light of about 2300K, which is obviously yellow light under human vision. LEDs can produce light sources with different color temperatures through the packaging process, giving many different options for road lighting.
2. Color temperature selection of LED street lights
The currently used LED packaging process can obtain LED white light sources with different color temperatures by applying phosphors with different excitation wavelengths and adjusting the amount or ratio of the phosphors.
The color temperature of light emitted by different light sources is different. The characteristic of low color temperature light sources is that in the energy distribution, the red radiation is relatively more, which is usually called "warm light"; after the color temperature is increased, in the energy distribution, the blue radiation is higher. The ratio increases, often referred to as "cold light".
For white LEDs, the low color temperature light source has a relatively large proportion of yellow light, while the high color temperature light source has a relatively large proportion of blue light. From the perspective of human vision, low color temperature gives people a warm and stable feeling, while high color temperature gives people a cold and refreshing feeling.
3. The relationship between color temperature and light effect
Under the technical conditions of early phosphors, LEDs with cool white light sources have higher luminous efficiency. Compared with color temperature, people pay more attention to the physical properties of light effect. The main method to improve the light efficiency is to improve the excitation efficiency of the phosphor, and the excitation efficiency of the YAG yellow powder is much higher than that of the orange powder.
High luminous efficiency not only brings higher energy saving rate, but also reduces the cost of lamps and lanterns, making the products more competitive.
With the development of various LED technologies, the efficiency of LED chips has been continuously improved, and the packaging process has also been continuously improved. The luminous efficiency of white LEDs in current applications has already exceeded the 160lm/W threshold, and there is still room for improvement in the future. And the technology of phosphor powder has also made some breakthroughs. At present, the difference in the light efficiency of white LEDs in various color temperature ranges is not as large as before. less than 6%.