1, Glare (Glare) is often used to describe bright sunny beaches or snowy mountain tops such an environmental condition, 1984 North American Society of Lighting Engineering definition of glare: in the field of vision due to far greater than the eye can adapt to the lighting and cause annoyance, discomfort or loss of visual performance of the feeling. 2, the source of glare is divided into direct, such as sunlight, too strong lights, etc., and indirect, such as reflections from smooth object surfaces (highway pavement or water, etc.). 3.According to the consequences of glare, there are three main types of glare: discomfort glare, light-adapted glare and funeral glare. 4, discomfort glare refers to the discomfort felt in some too bright environment 5, light-adapted glare refers to a phenomenon when a person walks into the sunlight from a dark movie theater (or underground tunnel) with reduced vision in both eyes. 6.Deactivated glare is a phenomenon that causes a decrease in the contrast of the retinal image of the human eye due to the glare source of the surrounding clutter, which leads to difficulties in the resolution of the image of the brain, similar to the projection of a slide projector on the wall caused by the interference of the bright light next to the image quality degradation performance.