Why CFL gives bluish white light and not good for eyes ? Compact Fluorescent Lamp was developed with aim of energy conservation. CFL requires a start up time to attain full brightness. The light colour is slightly greenish at power on which changes to blue white after the warm up period of a few minutes. This bluish white colour is due to the presence of Ultraviolet rays from the excited mercury vapour. The CFL has a resonant converter to generate high frequency AC to excite the mercury vapour filled inside the tube. The excited mercury atoms generate UV rays that produces fluorescence in the Phosphor coating of the tube. The phosphor coating then emits visible light with some UV fraction that gives bluish white colour to the light. Unlike ordinary bulb, CFL generates secondary light. The light is not directly from the filament, but from the phosphor coating. Actually this secondary light is not friendly for the eyes since the human eye is adapted for natural direct lights such as sunlight and light from flame. UV ray is also not good for the eyes. Low quality CFL generates large amount of UV rays. This can cause eye strain if the light is viewed long time. Some CFL Facts 1. Usually the CFL has longer life span, but it will be reduced by many factors like voltage spikes, mechanical shock, lamp orientation, operating voltage, frequency of AC applied etc. Good poisoning of CFL is the downward orientation from the roof. Fixing on the wall will reduce its life. 2. Do not hold the tube while inserting into the holder. This may detach the tube from the base. 3. In areas of low voltage in power lines, CFL will have very short life. 4. Another important factor that affects CFL is its frequent on and off. If the CFL is switched on and off at an interval of 5-6 minutes, the life span greatly reduces.
Posted on: Mon, 30 Sep 2013 16:56:06 +0000
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