Learn about "healthy lighting" in one article

　　Scientific research has found that light is one of the main driving forces of the human body's circadian rhythm system. Whether it is natural sunlight or artificial light sources, it will trigger a series of circadian rhythm responses. Light affects human health  varying degrees through visual and non-visual effects. Therefore, it is of great practical significance  advocate "healthy lighting" and improve light quality and comfort.

　　The so-called healthy lighting is  improve and improve the conditions and quality of people's work, study, and life through lighting, and  promote psychological and physical health.

　　The solar spectrum is the healthiest spectrum. The solar spectrum mainly includes ultraviolet, visible and infrared spectra. Ultraviolet light has the effect of sterilization and disinfection. It can kill mites and other microorganisms or pathogens, promote the synthesis of vitamin D, prevent and treat rickets and rickets, and prevent osteoporosis in the elderly. It has anti-inflammary and analgesic effects, promotes local blood circulation, and regulates immunity; Infrared rays have a good therapeutic effect on human tissue metabolism, blood circulation, and enhancement of human immune function; at the same time, it has a therapeutic effect on muscle spasm, muscle strain, soft tissue injury, and body tissue swelling.

　　The so-called healthy lighting mainly means that the spectrum of artificial light sources used for lighting should be as close as possible  the visible spectrum of the sun (i.e., imitating natural light lighting), and the lighting must meet the functional requirements of the place and the psychological requirements of people. It not only requires the comfort of lighting, but also satisfies people's psychological emotions in terms of color temperature, brightness, and harmony between light and shadow. On the basis of high color rendering index, reduce the relative energy of blue light (R12)  prevent blue light harm; increase the relative energy of red light (R9)  promote the body's physical and mental health.

　　A set of natural visible spectrum

　　1. Blu-ray problem

　　According  official statistics, the probability of my country's 7-12, 13-15, and 16-18 year-old students suffering from eye diseases is 45.71%, 74.36%, and 83.28%, respectively. The incidence of eye diseases among teenagers has surpassed Japan  become the world's largest country.

　　People generally attribute the reasons  two aspects. One is that children are stressed with homework and overuse their eyes; the other is that they are facing electronic products such as mobile phones and tablets for a long time. Two facrs cause eye fatigue in adolescents, resulting in decreased eye adjustment ability, which in turn induces eye diseases.

　　According  a research report issued by the International Commission on Illumination CIE in 2002 (CIE S 009/E:2012): Blue light can cause phochemical damage  the retina, mainly concentrated in the retinal pigment inner epithelial cells, and form arcs and blind spots on the retina. The eye can see things because rod cells and cone cells are distributed on the retina. The axial end of the retina has a place called the fovea. This is the area with the sharpest vision and the most abundant visual cells. It appears yellow because it is rich in lutein. Under normal circumstances, with age, the macular fovea ages and causes visual decline.

　　However, under long-term exposure  blue light, excessive blue light directly enters the retina and generates a large number of free radicals, which accelerates the oxidation of the macular fovea, and ultimately leads  the death of a large number of visual cells in the macular fovea, and this damage cannot be repaired by itself.

　　In April 2018, the Institute of Global Health in Barcelona, Spain (ISGlobal) announced that the longer the blue light exposure at night, the more people’s body rhythms will be broken, leading  an increase in the incidence of breast and prostate cancer. The results of this study "assessed the relationship between nighttime exposure  artificial lighting in Spain and the risk of breast and prostate cancer. It must be emphasized that excessive amounts of the spectrum in any band are harmful.

　　2. Blue light = blue light component?

　　The following four spectrograms from left  right are visible natural light, tungsten lamp (incandescent lamp), fluorescent lamp, and LED lamp.

　　The colors of the four light sources are natural light, warm color, white, and cool white. It can be seen that even the warm-colored light emitted by everyday incandescent lamps also contains blue light. The blue light component is universally present in all kinds of lamps and light sources. The difference is that blue light does not contain other color components. Moreover, the white light LED relies on blue light  excite the phosphor  emit yellow-red light, and then merge its own blue light gether  form white light, so the proportion of its blue light component is relatively more concentrated than other types of light sources.

　　3. Choice of artificial light source for healthy lighting

　　Figure 3 is the "IEEE PAR 1789-2015 Draft Risk Assessment of the Potential Health Effects of LED Lighting Flicker", the classification diagram of the hazard caused by the light source flicker  the observer, the green part is the imperceptible area (non-hazardous area), and the yellow is the low risk Area, white is the harmful area. The limit frequency that can be discerned by the human eye is about 60Hz, which means that it is difficult  distinguish between 60Hz, 100Hz and 3000Hz luminous frequency by vision. A large number of studies have pointed out that long-term exposure  a hazardous light source strobe environment can cause eye fatigue and vision loss, and dizziness, nausea, and nervous system damage.

　　Since both incandescent lamps and fluorescent lamps work directly under the power frequency, the frequency of their light emission is about 100Hz (see Figure 4 for the waveform), and the upper limit standard for the non-harmful fluctuation depth at this frequency is specified as 3.3%. Incandescent lamps that only rely on tungsten filaments  generate heat or fluorescent lamps with phosphor afterglow are difficult  meet this requirement.

　　When non-dimming, the LED is driven by a constant current and there is no stroboscopic problem; when dimming, the stroboscopic can be controlled below 3.3% by PWM and other control methods  achieve stroboscopic safety. Therefore, stroboscopic hazard is a major problem for traditional light sources, but there is basically no stroboscopic hazard for LED products.

　　On the other hand, due  the easy dimming of LEDs and the ability  integrate multiple chips in one lamp, better color reproduction can be achieved and visual fatigue can be reduced. Therefore, compared with traditional light sources, LEDs have more advantages in controlling stroboscopic hazards and color reproduction, and are also more energy-saving and environmentally friendly. Therefore, as long as the design is reasonable and scientific, LED lighting will be the best choice as an artificial light source for healthy lighting.

　　4. Health lighting LED product standards

　　Healthy lighting is an extremely complex system. Up  now, the country has no clear indicars on healthy lighting, and healthy lighting is still in the advancing and explorary stage.

　　At present, there are many healthy lighting products on the market, but the quality is uneven. They are more of a gimmick for business promotion. The market is chaotic. An authoritative, unified, and template-based healthy lighting standard is urgently needed  guide the healthy development of the healthy lighting industry. Although the formulation of health lighting standards is not an easy task, its importance cannot be ignored.

　　With the continuous development of the lighting industry, each technology has its own strengths in terms of energy efficiency and light quality, but the same thing is the importance of standards, because the quality, perform