Application of LED to the optimal illumination and color temperature analysis of classroom lighting -- an interview with Professor Yan Yonghong, School of architecture and urban planning, Chongqing Un

At present, students myopia rate is high, the research found that environmental factors associated with the onset of myopia rate is quite close, the classroom lighting is one of the most important influence factors. In order to improve this situation, to provide lighting and healthy environment for students, since 2008, the Yan Yonghong professor of architecture and urban planning, Chongqing University is in charge of the National Natural Science Fund Project "Research on classroom lighting based on the effect of biological health". In the past 3 years, she led the project team of the three kinds of photochromic T5 fluorescent lamp, LED lamp, under different illumination of the test of the psychological and physiological responses were tested. The main content includes the function of vision, visual fatigue, mental fatigue, learning efficiency test and pulse, heartbeat, respiration and other physiological indexes test; in order to further understand the different light stimulation effects on the brain, the project group also conducted EEG test.

At present, the results have not been completed, except for the EEG analysis. In order to further understand the significance of the research results on the industry, this is an interview with Yan Yonghong, Professor of architecture and urban planning, Chongqing University.

LED lighting has not yet officially entered the classroom lighting field

"Semiconductor lighting": the classroom as a special kind of indoor lighting places, which has the special requirements of the lamp?

Yan Yonghong: the classroom lighting not only has a great influence on students' eyesight, because of the non visual effect of the eyes, spectrum, different color temperature of light source light intensity differences will also affect the circadian rhythm of students, to generate excitement or fatigue, affect learning efficiency and physiological and psychological health. Therefore, the classroom lighting lamps should not only consider the light source color temperature, illumination on the impact of students, but also should pay special attention to the spectral safety of light source.

"Semiconductor lighting": LED lighting in the classroom is a kind of status quo?

Yan Yonghong: at present, the classroom lighting is mainly based on fluorescent light source, LED lighting has not yet officially entered the classroom lighting. Only in some experimental projects using the LED. At present, it is more common to replace the old T8 fluorescent tube with straight tube LED in order to obtain higher luminous efficiency. However, because many schools have adopted a higher luminous efficiency of T5 fluorescent lamps, therefore, the idea of LED applications in the future will be greatly constrained. Since the current price of LED light source is higher than that of T5 fluorescent lamp, it is not dominant in light efficiency. Therefore, if only to promote the concept of energy-saving LED classroom lights, I personally think that the prospects are not good.

High myopia rate is closely related to poor lighting

Semiconductor lighting: in your opinion, what is the market potential of LED lighting in the classroom?

Yan Yonghong: at present, the prevalence rate of myopia in China ranks second in the world, especially the poor eyesight rate of college students is as high as 82.68%. Compared with the fluorescent lamp, LED is more convenient to meet the requirements of spectral security. Our experiments also show that LED has better visual performance under the same color temperature and the same illumination. Therefore, from the point of view of the students to improve the health and ease the tension of students, LED has a greater advantage than fluorescent lamps, with great market potential.

Semiconductor lighting: what do you think are the advantages and disadvantages of LED in classroom lighting?

Yan Yonghong: compared with the traditional fluorescent lamp light source, LED light source is the biggest advantage of spectrum is easy to control, through the mixed light and other forms to form a specific spectrum needed to traditional blue chips with different fluorescent powder formulations, or use the multi spectrum chip, with strong flexibility. The fluorescence spectrum can only be achieved through the deployment of fluorescent powder formula, which has great limitations.

In addition, LED also has the characteristics of fast response, point to point control, flexible dimming, and so on. The use of this feature can not only achieve the interaction with the natural light, according to our latest research results, but also can be used for our upcoming dynamic health lighting system.

Compared with traditional fluorescent lighting, LED lighting also has some shortcomings. If the light is not as good as the traditional fluorescent lamp, the reliability and stability is poor, the price is high.

Classroom lighting 4000K light source as the best

"Semiconductor lighting": LED application in classroom lighting also need to solve the difficulties? The future will be improved from what?

Yan Yonghong: how to achieve more accurate distribution of light, improve the reliability and stability of the LED lighting system, reduce costs and so on are all LED to enter the classroom lighting needs to solve the problem. In addition, LED spectrum security issues should be given more attention to the industry. All of these require further research and improvement.

Semiconductor lighting: what conclusions have been made in the experiments on the classroom lighting that you have developed in LED?

Yan Yonghong: there are some following conclusions: firstly, the research on psychological experiments and survey results show that students of color preference is not immutable and frozen, but varies with the function of classroom, classroom lighting illumination level, as the basis for the choice of color is not reliable. Evaluation of a light source is a good classroom lighting light source, in addition to considering the subjective evaluation of students, students must also be considered for a long time in a specific spectral environment, large