1. High frequency lamp
The alternating current of the power grid is 50Hz, and its voltage waveform changes 50 times per second, while the change frequency of voltage amplitude is twice the change frequency of voltage waveform, i.e. 100 times / second. For fluorescent lamps (fluorescent lamps) that directly use alternating current, their brightness changes with the voltage amplitude at both ends of the lamp tube, so they will flash. The flashing frequency is the same as the frequency of voltage amplitude change, which is 100 times / s. The main change that the human eye can perceive is within 30Hz. Although the alternating changes of light and shade 100 times per second will not be perceived by us, these flashes have an impact on the human eye. If it is bright, the pupil of the eye will contract; When the light is dark, the pupil will enlarge. Therefore, direct use of AC fluorescent lamps is harmful to the eyes.
Electronic frequency converter is used in high-frequency lamps (such as energy-saving lamps) to change 50Hz AC into high-frequency AC (usually 30k-50khz), and then light the lamps with high-frequency AC. In the high-frequency lamp, the light changes tens of thousands of times per second. Because the human eye has no time to change, it can not feel the change, so it is "unchanged" to achieve the purpose of eye protection. The driving circuit of high-frequency lamp will have 30-50KHZ electromagnetic signal. Some people claim that it is harmful to human body, but there is no specific report or data proof, which needs further research and verification.
2. Electric heating lamp
普通白炽灯以及卤素灯(halogen lamp)的光谱连续，最接近自然光谱，所以实际上也是一种“护眼灯”。而且，因为交流电先加热灯丝，灯丝先发热再发光，由于灯丝有热容量，所以电源变化时，灯丝还仍然是热的，明暗变化不会象荧光灯(日光灯)那样明显，但白炽灯的能效非常低，60W以上的白炽灯已经被国家列为淘汰商品 。卤素灯是白炽灯的改进版，在填充的惰性气体内添加微量卤元素。与普通白炽灯相比，卤素灯具有体积小、光效高，寿命长的优点
The spectrum of ordinary incandescent lamp and halogen lamp is continuous and closest to the natural spectrum, so they are actually a kind of "eye protection lamp". Moreover, because the alternating current heats the filament first, the filament heats first and then emits light. Because the filament has heat capacity, when the power supply changes, the filament is still hot, and the light and shade changes will not be as obvious as fluorescent lamps (fluorescent lamps), but the energy efficiency of incandescent lamps is very low. White incandescent lamps above 60W have been listed as obsolete commodities by the state. Halogen lamp is an improved version of incandescent lamp. Trace halogen elements are added to the filled inert gas. Compared with ordinary incandescent lamps, halogen lamps have the advantages of small volume, high luminous efficiency and long service life
3. UIV OLED table lamp
UIV OLED lighting adopts low-voltage DC power supply, so there is basically no stroboscopic and no blue light and ultraviolet damage. It can manufacture large-area OLED panels, which is a key research plan in China. OLED lighting does not need to heat the filament to thousands of degrees Celsius, nor does it need to use mercury vapor to generate ultraviolet light to excite the phosphor to emit light. Because there is no multiple conversion process of electric energy, OLED lighting saves about 60% to 70% of electric energy than current energy-saving lamps. More importantly, OLED lighting will not produce pollution in the process of production and use. This resolves the risk of environmental damage caused by the current use of mercury in energy-saving lamps. It is understood that the mercury content of an ordinary energy-saving lamp is about 5 mg, which can pollute hundreds of tons of water once it seeps into the ground. Mercury can evaporate at normal temperature. After the waste energy-saving lamp tube is broken, the mercury concentration in the surrounding air can exceed the standard for hundreds of times. Once the Mercury entering the human body exceeds the standard, it will destroy the human central nervous system and even cause death. Hundreds of millions of mercury containing lamps are scrapped every year in China. Due to improper disposal, the amount of mercury released into the atmosphere and water environment is as high as dozens of tons