What is the difference between led lighting source and traditional light source?

Focusing on outdoor lighting 1 1, the data of the old brand free light are analyzed. According to the national lighting electricity consumption in 20 10, replacing traditional lighting products with high-quality LED lighting products can save electricity equivalent to the total power generation of 15 thermal power plants. A year can save 850 million cubic meters of coal for power generation. Reducing carbon dioxide emissions is equivalent to planting 38 million mu of forest. The difference between led lighting source and traditional light source is mainly in three characteristics: heat, electricity and light.

First, the characteristics of heat

Although LED generates little heat, it will generate high heat because LED lighting requires several watts of LED. Although the efficiency of LED is relatively high, this high efficiency only supports the work under small current. At high current and high temperature, the efficiency is low.

In addition, phosphor LED will lose energy when converting wavelength, thus generating heat. Continuous high temperature will lead to the decrease of the life of LED chip, phosphor and packaging resin. Therefore, in order to maintain the advantages of "high efficiency" and "long life" of LED, it is necessary to control the junction temperature of LED.

Second, the characteristics of electricity

LED power supply is very different from incandescent lamp and fluorescent lamp. Incandescent lamps can be directly connected to 220V AC. Although fluorescent lamps have ballasts and switches, they also use 220V alternating current. The power supply of LED needs constant DC current, so it needs to convert 220V AC into DC. The low efficiency of power supply will directly affect the efficiency of the whole lighting fixture, so improving the efficiency of power supply is particularly important for improving LED lighting.

There are two main ways to adjust LED lights. One is to change the constant current, the other is to change the pulse modulation. LED emits light when electrons and holes recombine, and the light beam depends on the current. When the current is small, the light beam is basically proportional to the current, but when the LED current is large, the heat increases, resulting in low luminous efficiency and the light beam is not proportional to the current.

In the method of changing the pulse duty ratio, because of Talbot-Plateau effect (human eyes will feel the average brightness in the repeated time after receiving the instantaneous flash repeatedly), the brightness can be changed according to the pulse duty ratio.

Third, the characteristics of light.

Compared with incandescent lamps and fluorescent lamps, the LEDs of 1 emit less light, so more LEDs are needed. At the same time, because of their small luminous area and high brightness, human eyes are prone to dizziness. In order to reduce the brightness, it is necessary to use a diffuser. However, if a diffuser is used, the light diverges in all directions, which reduces the light efficiency.

The light distribution of LED, incandescent lamp and fluorescent lamp is different. The so-called light distribution refers to the direction of the light source and the luminous intensity in all directions. Even for light sources with the same beam, if the light distribution is different, the illumination distribution will be different. Sometimes, the illuminance in the original predetermined place decreases, but the illuminance in other places increases.

In order to reduce the waste of light and control the distribution of light, lenses and mirrors are needed. LED itself has the advantages of small luminous area, semi-spherical light radiation range, rotational symmetry of light distribution and so on. With lenses and reflectors, a good light source can be formed.

Others are in the light source properties, as well as the spectrum. The emission spectrum of LED is concentrated in a narrow range of specific wavelength and does not emit infrared rays. Therefore, when you don't want to heat the irradiated object, you'd better use LED. But LED itself will generate heat, so we should pay attention to prevent it from conducting heat. Furthermore, it should be noted that the color temperature of the phosphor type LED will also change.