Current lamp introduction
incandescent and halogen lamps (halogen lamp) spectrum is continuous, closest to the natural light spectrum, so it actually is a "eye-light". And, because the alternating current heats the filament, filament heat glow again, due to the thermal capacity of the filament, so when a change of power, the filament is still hot, the lighting changes do not like fluorescent lamps (fluorescent lamp) so obvious but very low energy efficiency of incandescent bulbs, 60W incandescent lamps have been washed out by the State as a product  . Improved version of halogen incandescent, inert gas fill to add trace halogen elements. Compared with incandescent, halogen, with small size, high efficiency, long life advantages [2-3]
AC 50Hz of China's power grid, the voltage waveform changes 50 times per second, and voltage changes the frequency of the voltage waveform frequency twice times or 100 times per second. Direct use of alternating fluorescent lamps (fluorescent lamps), its brightness with the ends of the lamp voltage change, so will Flash, flicker frequencies the same frequency as the voltage change, 100 times per second. Human eye can perceive the major changes for the 30Hz light 100 times per second alternating light and dark will not be perceived by us, these Flash effects to the human eye. Such as light, contraction of the pupil in the eye; when the light and dark, the pupil will zoom. Direct AC power fluorescent lamp used for eye injuries.
high frequency light (such as energy-saving lamps) use of electronic converters, high frequency AC 50Hz AC (usually 30k-50kHz), and high-frequency alternating current lamp. At the high-frequency light, bright change tens of thousands of times per second, because the human eye no time to change, you feel no change, so is "unchanged", and achieve the purpose of eye. Driving circuit of high frequency light has 30-50kHz electromagnetic signals, it is claimed that it is harmful for the human body, but there are no reports or evidence, which requires further research, verification.
using an adapter, lighting is mainly used in large-scale landscape lighting, and light quality requirement of situations, low energy consumption, less suitable for high with an eye to the environment, because the ratio of Blu-ray components is too strong , vulnerable eyes. In addition, the small lamp bead loss, attenuation problems, likely to cause the entire lamp scrapped, universal lighting small, narrow color spectrum, belonging to a monochromatic light source, will have certain effects on the optic nerve. LED lamps also have the advantage of relatively low cost of electronic components, lamps low prices. Color temperature warm white LED lights (yellow, 2700-3000k or so), and white (5000-7000k), and cold white (8000-12000k) in three categories.
DC nursing eye lamp
using DC ballast, through put Exchange electric first change into voltage, and current smooth of DC electric, with DC electric lighting, reached real no frequency Flash, and using Shi issued of light and natural light as is continuous uniform of light, is soft, can avoid vision fatigue, and solution has inductance ballast fluorescent of frequency Flash problem; due to used of is DC technology, no any exchange fluctuations, also avoid has by high frequency electronic ballast by caused of electromagnetic interference signal. DC fluorescent technology is difficult, expensive, and many companies are reluctant to use the technology.
incandescent light spectrum is continuous, but compared with natural light yellow, black and white contrast of light will be illuminated objects down.
fluorescent light is white, but because it is made up of 50 Hz alternating current direct light, so the brightness to 100 times per second the frequency change, this is Flash. Flicker under fluorescent lights for a long time, eye fatigue.
most of the "eye-light" 50Hz principle is the use of electronic rectifier frequency increased to 30-50kHz. However, national lamps quality supervision detection Center and Fudan University electro-optic Institute test results is showed that, used high frequency ballast production of "nursing eye lamp", its frequency Flash fluctuations depth in 7.27% to 24.03% of range, and incandescent compared no significantly differences, and strictly meaning Shang of no frequency Flash is refers to frequency Flash fluctuations depth is less than 5%, that is General of "nursing eye lamp" and no reached no frequency of requirements. Most so-called "eye-light" is not flashing, just Flash the amplitude, frequency increases, the human eye can't tell, so it feels the same as no Flash. Meanwhile, electronic ballasted lamps for high frequency oscillation will produce electromagnetic interference.
LED lights are low voltage DC adapters, strobe light and electromagnetic interference-free signal, but its Blu-ray components were too strong, the human eye is not very good.
therefore, can solve the strobe and electromagnetic interference-free signal DC fluorescent lamps gradually attention. DC fluorescent lamps will buck rectifier to DC mains electricity, enter a special lamp, avoiding a strobe signal and high frequency electromagnetic interference. DC fluorescent lamp technology had not yet been promoted.
no matter what light, as long as non-natural light, have a certain influence on Visual, so try to use mixed light sources. In addition, to protect the eyes, the most important is the use of light. Should on the one hand to ensure the watch area light enough, and shade cover the light source so as to avoid glare in addition to avoid a lamp too close to the watch area (book/desktop), the led light is too bright.