Design requirements for high-power LED tunnel lights
(1) Basic lighting must be set in the tunnel whether it is day or night. When the vehicle enters the tunnel during the day, the brightness of the road surface should gradually decrease, so that the driver's vision has an adaptation process, and the entrance section is divided into the introduction section, the adaptation section and the transition section.
(2) Determine the length (S) of the introduction section, the adaptation section and the transition section, which is usually determined according to the vehicle speed (V) and the adaptation time of T=2s, which can be estimated by S=VT/3.6m; the transition section should also be set for the exit section. Lighting, same as entry section in two-way traffic situations.
(3) No enhanced lighting shall be provided at the entrance and exit at night, and street lighting shall be provided outside the tunnel, and the brightness shall not be lower than 1/2 of the basic brightness in the tunnel; emergency lighting shall be provided in the tunnel, and its brightness shall not be lower than 1/10 of the basic brightness.
(4) According to the provisions of China JTJ026-90 "Code for Design of Highway Tunnels", the length of the tunnel entrance lighting interval and the minimum brightness standard of the road surface are designed according to the national requirements.

Design scheme of high-power LED tunnel light
Selection of LED light source: LED single-watt lumen output is the basic indicator to determine whether LED tunnel lights have practical value. According to requirements, the single-watt lumens of LEDs used in LED tunnel lights should reach more than 80 lumens. After nearly three years of LED lighting After the rapid development of efficiency, the luminous efficiency of LEDs that can be supplied in large quantities at this stage has reached more than 90lm/W, and the brightness is still increasing. Table 2 provides the main technical parameters of the high-power 1W white LEDs that have been mass-produced on behalf of several leading international manufacturers. Epistar, Osram and Cree lamp beads can be used as the design light source, and the LED light source has a variety of different color temperatures to choose from. Choosing an LED light source with a color temperature of 4000~6000K similar to sunlight can effectively reduce "bright holes" and "" black hole" effect.

LED Tunnel light distribution design
According to the tunnel lighting requirements, different light distribution lamps are used according to different lighting sections. According to the optical principle and the characteristics of high directivity of the LED light source, a reasonable light distribution is adopted. When the brightness or illuminance requirements are met, the power of the lamps is reduced to achieve purpose of energy saving.
(1) The introduction section, adaptation section, transition section and exit section of the tunnel entrance section adopt asymmetric lighting distribution (backlighting), under the same illumination conditions, compared with ordinary lighting, the road brightness can be improved by 121%, and at the same time , takes advantage of high directivity, strictly controls the light intensity in large-angle directions, and eliminates most of the glare.
(2) In the basic section of the tunnel, the current common light distribution types include concentrating light distribution, side-emitting light distribution, and Lambertian light distribution. Different applications are suitable for different light distribution forms. For example, bat-wing light distribution should be used for road lighting, and spotlight should be concentrated light distribution. Due to the particularity of tunnel lighting, the arrangement density of lamps in tunnel lighting is very high, so the secondary light distribution form of lamps in tunnel lighting is different from general road lighting. In tunnel lighting, both bat-wing light distribution and Lambertian light distribution can meet the requirements of illuminance uniformity, which is mainly due to the relatively small lamp distance in tunnel lighting. Figure 1 shows the light distribution in the C0 direction of the two LED tunnel lights. The left is the bat-wing light distribution commonly used in road lighting and tunnel lighting, and the right is the Lambertian light distribution. The bat-wing light distribution is adopted, that is, the wide-band symmetrical lighting distribution. Under the same illumination conditions, compared with ordinary lighting, the road brightness can be increased by 64%, and the road brightness uniformity can be improved. For more visit www.szbjhkj.com