First of all, let me give you some popular science: Glare refers to the visual conditions that cause visual discomfort and reduce the visibility of objects due to inappropriate brightness distribution in the field of view, or extreme brightness contrast in space or time. A feeling of light in the visual field that the human eye cannot adapt to, which may cause disgust, discomfort or even loss of vision. Excessive brightness or excessive brightness changes before and after in a certain part of the field of view. Glare is one of the important causes of visual fatigue.

       In order to obtain a comfortable, high-quality lighting environment, it is necessary to suppress glare by improving lamps and lanterns. In recent years, indoor lamps exported to the EU have anti-glare standards, that is, UGR<19, or even lower. In fact, as early as 1995, CIE (International Commission on Illumination) has proposed the concept of anti-glare lamps and UGR (Unified Glare Rating) as an indicator to evaluate the uncomfortable glare of indoor lighting environment. With the development of LED chip technology, LED lamps are getting brighter and brighter, and uncomfortable glare is becoming more and more serious. So in 2014, the EU made the UGR limit a mandatory standard for lamps, rather than just as a reference as before.

The so-called "UGR<19" only meets the most basic glare requirements in schools and offices. In fact, in actual use, customers will still prefer lamps with smaller UGR. If you look at the following table of the corresponding relationship between UGR value and uncomfortable glare level, you will understand: UGR=19, which actually means discomfort. The lower the UGR value for work and study places, the better.

     Many people have a misunderstanding of UGR, thinking that it is the same as power and light efficiency, and it is a parameter of the lamp itself. In fact, the meaning of UGR is the discomfort of the lighting environment to the human eye. It is a value that characterizes the uncomfortable glare degree of the entire lighting space and is calculated by various parameters related to the generation of glare. In simple terms, the UGR value is not only related to the luminaire, it is related to the size of the room, the reflectivity of the room, and the viewing direction of the observer.