The lamp I just bought is very bright when I use it. After use for a long time, the brightness of the lamp will gradually decrease until it is slowly extinguished. We all know that this is the life of the lamp is slowly shortening, until one day it is not bright, it will die. A lot of people can't help wondering, why will lamps and lanterns have such a process, what is the reason?
In fact, in the final analysis, this is the lamp light failure problem, simply said, lamps and the human body, with the growth of service life, the function of the lamp mechanism is in decline. No matter it is incandescent lamp, energy-saving lamp, or LED lamp can not avoid the problem of light decay.
The light failure of lamps and lanterns means that after a period of lighting, the light intensity will be lower than the original light intensity, and the low part is the light failure of lamps and lanterns. Different types of lamps cause different causes of light decay.
The incandescent light fades
For ordinary incandescent lamps, the larger the bubble shell, the smaller the light decay, that is, in direct proportion to the amount of tungsten evaporation deposition blocking light output. The gas-filled bulb, on the other hand, will lose less light because part of the gas prevents the tungsten filament from evaporating.
If you have an incandescent lamp with the same filament, in a different size of the bubble shell, relatively speaking at the same point in time the light decay of the big bubble shell is smaller than the small bubble shell.
In addition, the same is the inflatable bubble, large glass bulb interior space, gas convection to the glass shell has a relatively large heat dissipation area, relatively small glass shell lamp temperature is much lower, the temperature of the filament is also relatively low, low luminous efficiency, tungsten wire evaporation rate is also low, so the light decline is smaller.
Energy saving light failure
Incandescent lamp will cause light decline because of the size of the bulb and the amount of evaporation of tungsten wire, energy-saving lamp light decline reasons are relatively complex, generally caused by the following reasons:
◆ Phosphor deterioration, in the working process of energy-saving lamp, UV will make the phosphor color center, resulting in a new absorption band in the lamp, so that the phosphor brightness attenuation.
◆ The formation of light absorption film, energy-saving lamp after a long time of discharge work, on the surface of the phosphor will form a layer of black light absorption film, the existence of this layer of light absorption film will cause the reduction of light output.
◆ Lamp black, energy-saving lamp working, glass tube surface will have a large number of mercury ions or mercury atoms exist, mercury ions and other ions in the glass tube for ion exchange, over the years, the glass tube will be blackened, resulting in energy-saving lamp light decline, affecting the luminous efficiency.
LED light failure
LED lamps are better than incandescent and fluorescent lamps, but they can't completely overcome the problem of light decay. There are two main factors for LED light decay:
1. Quality problems of LED products
◆ The quality of the LED chip is not good, the brightness attenuation is fast.
There are defects in the production process, LED chip heat dissipation can not be well exported from the PIN pin, resulting in LED chip temperature is too high and chip attenuation is aggravated.
2. Use conditions
◆ LED is driven by constant current. Some LED lights are driven by voltage, which causes the LED to decay too fast.
◆ Driving current greater than rated driving conditions.
In fact, there are many reasons for LED product light decay, but the most critical or heat dissipation problem. The better the heat dissipation performance, the lower the LED operating temperature, the smaller the light decay, the longer the LED life.
Light failure is a necessary process of the lamp work, we should try to choose the quality and heat dissipation performance of the lamp, in the use of the process should also try to reduce the work load of the lamp, in order to delay the speed of light failure, prolong the life of the lamp.
