2022

LED Tunnel Lights: Do you need a protective cover?

Currently, there are several ways to protect LED lenses: with or without a protective cover. To compare the two methods, we made two sets of identical lamps, one with a flat glass lens and the other with a lens in direct contact with air. For comparison, we installed these lamps in a tunnel -- the most polluted environment for lighting applications. The results clearly show that the use of flat glass lampshades can maintain light flux, thereby improving safety, reducing maintenance requirements and improving energy efficiency.

If the lens of the lamp is not protected, the lighting level in the tunnel can be reduced to a dangerous level. If the lens is contaminated by direct exposure to air, the precise calculations that have been made in designing a tunnel lighting solution to meet the necessary lighting levels and energy saving requirements become futile.

introduce
The main objective of tunnel lighting is to ensure good visibility, both during the day and at night, to allow drivers to travel safely, comfortably and with confidence through the tunnel at a certain speed. At the same time, these conditions should be at least comparable to those of the entrance section of the road leading to the tunnel.
In order to achieve this objective, road users entering the tunnel should be able to obtain good visual information about the condition of the road section ahead and be able to observe the presence and movement of potential obstacles (specifically, other users of the road). It is also very important to maintain this light distribution efficiency for a long time.
HID lamps are always made in the same way: light source, reflector, protective cover. Other than changing the type of light source, the lamps haven't changed much. With the advent of LED technology, the components of the lamp can be changed. The first is often to replace the reflector with a lens. Some types of lenses allow lamps without a shade. Reducing this component has the obvious benefit of increasing the luminous flux output of the luminaires.
However, the air in the tunnel is very erosive. Because the protective cover or lens is heavily contaminated, it needs to be cleaned regularly to maintain the required light distribution requirements. The accumulation of dust on an object depends on its shape. The shape of the luminescent surface (lamp) differs between a protected and unprotected shade.