What are the hazards of LED glare and how to protect it?

Update:16-07-2021
Summary:

Dazzle refers to a visual phenomenon that causes eye di […]

Dazzle refers to a visual phenomenon that causes eye discomfort or reduces eye resolution due to improper brightness distribution in the field of view, or strong brightness contrast between the light source and the surrounding environment. Glare is also one of the common light pollution in modern society, such as the light pollution caused by the excessively strong reflected light of glass in the city, and the glare of oncoming car headlights at night. Studies have shown that long-term glare can physiologically cause the loss of human eyesight, cornea and iris damage; psychologically, it can also cause people to feel restless. Especially for newborns and those with fragile eyes, glare pollution should be avoided as much as possible.

LED light source has the characteristics of small size, high efficiency and long life. With the formulation and introduction of the government’s "Twelfth Five-Year" special plan for the semiconductor lighting energy-saving industry and the launch of the 863 plan "Semiconductor Lighting Project", my country’s LED lighting industry has also Ushered in the best opportunity for development. The development model of smart lighting + LED has further promoted the development of "green lighting" led by the LED industry chain. But as a new type of green light source, in theory, LEDs, like other traditional light sources, can cause a certain amount of radiation damage to the human body, and the light density of LEDs is stronger and the light radiation energy is more concentrated, resulting in a stronger sense of glare than traditional lamps. From this we can see the necessity and urgency of LED anti-glare.

How to evaluate glare? The original industrial and civil lighting design standards stipulate that the direct glare of indoor general lighting is limited according to the brightness limit curve. This limitation method is only for the glare of a single lamp, and cannot characterize the total glare effect of all lamps in the room. Therefore, CIE proposed a unified glare value (UGR) calculation formula on the basis of comprehensive glare calculation formulas in various countries. When the UGR value is less than 19, the degree of glare is acceptable to the human eye. Therefore, for indoor lighting, UGR19 is the glare evaluation index for indoor lighting.

How does indoor lighting control the UGR value for glare protection? For LED lights, the LED light source is a point light source, with strong directivity, and the light is not soft. If the light-emitting surface is not processed, you will see a strong glare of LED lamp beads, which cannot meet the UGR19 standard. Therefore, a layer of lampshade will be added to the outside of the LED lamp bead, and some light diffusers will be added to the ordinary lampshade to achieve the purpose of uniform light. This is the first generation of anti-glare board. However, with the increase in LED power, people's aesthetic requirements for the appearance of lamps and lanterns, and the increase in the demand for indoor brightness, ordinary lampshades can no longer meet the demand. The second-generation anti-glare diffuser with microstructure optics came into being. Its principle is based on the principle of light reflection and refraction. Through optical design, a concave-convex optical structure is prepared on the surface of the lampshade, which can change the light purposefully and predictably. The propagation path further achieves the effect of scientific light control. Compared with the diffuser with added light diffuser, because there is no occlusion of the diffuser, the appearance is crystal transparent instead of milky white, so it has better light transmittance, and the regular arrangement of the microstructure makes the lamp more attractive , More suitable for high-power LED ceiling chandelier.

Therefore, when choosing a lamp, not only should pay attention to indicators such as color temperature, light efficiency, brightness, etc., but also not forget to evaluate the glare value and confirm whether the lamp has been treated with anti-glare processing. Living under a comfortable and soft light similar to sunlight is the pursuit of healthy lighting.
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