the led display has the characteristics of high brightness. if the brightness output of the led display reaches 8000 cd/m2 in the dark night, it will cause serious light interference.
1 classification of optical safety
generally speaking, light safety can be divided into the following two categories: photobiological safety and interference light.
photobiosafety
the main research areas of this type of light safety include ultraviolet, infrared, blue and visible light radiation damage to human tissues. common photobiological hazards include the harm of photochemistry ultraviolet to human skin and eyes, the harm of blue light to human retina, the harm of infrared laying to eyes and the harm of light and heat to skin, etc.
in all sensory organs of human body, the eye is the most important part. its self-repair ability is relatively weak. once exposed to external optical radiation, it will cause irreversible damage to the eyes. even visible light may damage people’s eyes. for example, blue light with shorter wavelength will cause damage to photoreceptor cells of retina, and in severe cases, it may cause the dysfunction of pigment epithelium. chemicals, such as high intensity radiation, can cause thermal damage to the retina.
interference light
the interference light can be divided into two types: direct and indirect. the former refers to the decrease of visual resolution caused directly by the luminous body with high brightness in the field of vision, while the latter refers to the problem caused by the reflection of the light projected object surface into the human eye.
after investigating some domestic manufacturers of led display screen, it is found that the maximum brightness of led display screen is 6,000-8,000 cd/m2, which does not reach the lowest brightness of photobio-safety problems. from this, it can be seen that led display screen will not cause photobio-hazards to human retina, including blue light hazards. in view of this, the following focuses on the analysis of interference light of led display screen.
2. the causes of interference light in led display screen
self reason
the led display has the characteristics of high brightness. if the brightness output of the led video display reaches 8000 cd/m2 in the dark night, it will cause serious light interference.
location cause
the closer the distance between the observer and the display screen, or the larger the diagonal angle between the position of the observer and the display screen, or the more convergent the direction of the observer’s line of sight and the display screen, the more serious interference light will be produced.