Spectrometer Applications Extend to Tunnel Lighting


MK350S Premium Spectrometer

Do you know UPRtek’s spectrometer guarantees the quality of the project and achieves safety, green, smart and technological goals? In this article we will share the user experience for you. We noticed that UPRtek spectrometer is not only used in landscape lighting and plant lighting, but also in many other fields. It can be said that as long as you have need in measure light, the spectrometer can help you to find the best solution and solve the problems in quality of lighting.



According to a user of UPRtek spectrometer, he applied UPRtek’s spectrometer in tunnel lighting detection. At first, he did not know that the spectrometer could also be used in the field. After having deeper understanding of the product, he found that the spectrometer can be used in road lighting or outdoor lighting to collect and analyze data, and the project can be completed in a more efficient way by using the spectrometer for light measurement.



Before we learn more about spectrometer applied in tunnel lighting, we need to know the difference between luminance and illuminance, because it is related to the location of the lamps in the tunnel, and it has effect on the safety of driving.
First, luminance is the light source or the object under the light reflects the light into human eye. It is applied in outdoor lighting in general; it considers direction and how much luminance will be determined by the angle and intensity of light, so that human eyes will see different amount of luminance. For the tunnel lighting, the luminance is not high, it is between 1~2nit normally. But for the entrance of the tunnel area is between 120~240nit, which is according to its structure and the type of lighting with different luminance design.


Evolution of measurement tools

The main use of illuminance is applied in indoor lighting, the measurement and inspection method is easier, and the amount of illuminance is related to light distribution curve and luminous flux. Normally, we were used to or gave suggested specification of the illuminance for office lighting with 500lux.


Evolution of illuminance measurement tools

For the measurement of tunnel lighting, the purpose is to accurately assess whether the driving environment is safe or not, the luminance and uniformity of the road surface are usually used as the main evaluation parameters, and the illuminance value is used to confirm whether the light output of the lamp is reasonable. At last, the ratio of these two indicators are used as a reference for the reflectivity of the road surface, which is the status of road pavement and it will be passed to the road management office for road cleaning and road paving evaluation.


Tunnel real scene vs. False color images

For general road lighting, they will consider the adaptation of bright and dark for human eye. Bright adaptation is when people come from the dark environment to the bright environment, we could adapt the changes very fast, which are through the action of cone-shaped cells; on the other hand, bright adaptation is from bright environment to dark environment, but we adapt the changes lower, which is through the action of rod-shaped cells. Therefore, if the design of tunnel lighting is unreasonable inside the dark tunnel and at the entrance or exit of the tunnel will affect the safety of driving. For example, if the design of tunnel lighting is not enough at the entrance, drivers will see a black scene in the front road, and then step on the brakes as natural reaction. This is called the “black hole effect.”

Therefore, before entering the tunnel, there is a luminance meter placed at the safety stopping distance outside the tunnel. It will measure the brightness of the tunnel entrance and the surrounding. The measured data will be used as a reference for switching the light inside the tunnel accordingly and provide a safest and most comfortable road environment to drivers.

Taiwan’s Jinshan Tunnel



Human eye’s perception is different in the daytime and nighttime, and spectrum can analyze the relationship between light source and human eye. At present, the trend of tunnel lighting design has been changed from traditional high-pressure sodium gas lamps to LED lamps. LED lamps are obviously superior to high-pressure sodium gas lamps in terms of S/P vision ratio and color rendering index. Using spectrometer inspect the light in a semi-closed tunnel space, it is not only process the basic LUX measurement, but also could measure the flicker, color tolerance and chromaticity characteristics of the LED lighting fixture accurately. It has a fairly complete analysis and assistance for the tunnel lighting pre-planning and post-acceptance inspection.


Human visual curve and light source spectrum


Spectrometer Analyze Flicker Characteristics


Spectrometer Analyze Color Tolerance Characteristics


Spectrometer Analyze Chromaticity Characteristics

It can be seen that the spectrum plays a key role in tunnel lighting. UPRtek’s handheld spectrometer is not only measure the spectrum, but also easy to use. As long as you aim at the measurement range, the result will display immediately on the screen, which reduces a lot of time for data analysis and calculating the results. So now you may walk and play around the world with the spectrometer in your hand.

Note1: This article was also issued on WeChat : https://mp.weixin.qq.com/s/o60csgnAqsBRBsThyrNKEg
Note2: Released on 2019/06/11

Visual Merchandising, LED Lighting Solutions-Handheld Spectrometer

MK350S Premium

MK350S Premium is a Handheld Spectrometer with Muli-Functions in itself. It's not only a Spectrometer, but also can be a Quantum PAR Meter, Blue light Detector and Oscilloscope. The