1.Characteristics of heat Although LED has very little […]
1.Characteristics of heat
Although LED has very little heat, it will produce very high heat because of the need to use multiple watts of LED in LED lighting. Although the efficiency of LED is relatively high, high efficiency only supports the operation in micro current. Under the condition of large current and high temperature, the efficiency is low.
In addition, the LED of the phosphor type loses energy when converted to wavelengths, resulting in heat. Persistent high temperature results in reduced lifetime of LED chips, phosphors, and encapsulated resins. Therefore, in order to keep LED's "high efficiency" and "long life" advantages, it is necessary to control the junction temperature of LED.
2. Characteristics of electricity
LED power and incandescent light, fluorescent lamps are very different. The incandescent lamp can be directly connected to the alternating current of the 220V. Although there are ballasts and switches for fluorescent lamps, they also use 220V alternating current. The LED power supply requires a constant DC current, so the AC 220V is converted to dc. The efficiency of the power supply is not high, will directly affect the efficiency of the entire lighting, so improving the efficiency of the power supply for improving the efficiency of LED lighting is particularly important.
There are two main ways to regulate LED light. One is to change the constant current, and the other is to change the pulse modulation. LED is the luminescence of electrons when combined with holes. The beam depends on the electric current. When the current is small, the beam is basically proportional to the current, but when the LED current increases, the heat increases, causing the luminous efficiency to decrease, and the beam and the current are not in direct proportion.
In the method of changing the pulse duty cycle, the brightness of the pulse can be changed according to the pulse duty cycle due to the Talbot-Plateau effect (the average brightness of the human eye will be felt in the repeated time after repeated flash flashes).
3.Characteristics of light
Compared with incandescent lamps and fluorescent lamps, 1 LED emit less light, so we need to use more than one LED. At the same time, because of the small luminous area and high brightness of LED, it is easy to vertigo if the eyes look straight at us. To reduce brightness, diffusion plates are needed. However, with the diffuser, the light diverges in all directions, reducing the efficiency of light.
The distribution of light in LED, incandescent and fluorescent lamps varies. The so-called light distribution refers to the direction of the light source and the intensity of illumination in all directions. Even if the light source of the same beam is different, the illuminance distribution will be different if the light distribution is different. Sometimes there will be places where you want to shine, and the illuminance will decrease and the rest will increase.
To reduce the waste of light and to control the distribution of light, use lenses and reflectors. LED itself has the advantages of small luminous area, light radiation range in the hemisphere, light distribution, rotation symmetry, etc., coupled with lenses and reflectors, it can form a good light source.
Other in the light properties, there are spectra. The emission spectrum of LED is concentrated in a narrow range of a specific wavelength, without infrared radiation. Therefore, it is better to use LED when you do not want the radiation to heat up. But LED itself gets hot, so it's important to guard against heat conduction. Also note that the LED temperature changes in the phosphor type, and the color temperature changes as well.http://www.outedsionbulb.com/