He Kaiwei: LED lighting and visual cognition (Figure)



Excerpts from the first China LED Semiconductor Lighting Summit Forum, Director of the LED Promotion Center of Xiamen City, Mr. He Kaixuan:

Dear Secretary-General, good morning, ladies and gentlemen, I will briefly introduce the issues related to LED lighting and visual cognition. Although I have been in the industry for a long time, I used to do eye research. The current status of the industry is not to know LED. I don't know LEDs when I understand lighting, I don't know LEDs. I hope to give you a publicity here, especially for my own eyes, especially the physiological and optical aspects.

We talk about the characteristics of LED lighting, there are light sources, objects, eyes, should be these three elements, lighting sources, if there are power sources, light sources, lamps and controllers from the perspective of energy saving, the objects being illuminated have absorption reflection and spectral characteristics, These two are objective physical quantities. The human eye is controlled by the brain and is also affected by the psychological.

LED display speed is very fast, can meet people's requirements, and energy saving, environmental protection, can achieve healthy lighting. Here is a point of view. The light of radiation is the physics of objective physics. This is related to the human eye, especially the subjective light related to human psychology. The units used now are related to the subjective subject. The human eye is made up of various cells, the cone cells are sensitive to color, and the rod cells are only sensitive. Photometry is the most developed and developed. LED is dynamic, not a source of thermal radiation. The original idea of ​​thermal radiation and the concept of correlated color temperature are not used in the LED industry. The new light source has developed in the future. .

The concept of index is displayed, which should be corrected. It should be developed. Now the display of LED, chromaticity is not the concept of traditional light source. Now the calculation result of LED is inconsistent with the traditional calculation. How to test CID based on recent test The results of the index are shown. From the history of chromaticity diagrams and chromatic aberrations and display indices, there have been six or seven changes since 1931 to 1935, and new developments have recently taken place.

Now introduce this picture to everyone, we know that the range of brightness that human eyes can perceive is very wide, the minimum is 10-18, the human eye can perceive the energy of the five photons entering the retina, some are almost the same, the perception is not formed. Vision, just feeling bright, people can see the sun at noon at noon, probably ten times the power of nine. Usually 3 square meters per square meter, there are 1.5 million cells near the center, feeling the most important feeling of color, mainly the feeling of the day, you can feel the shape and color. In the evening, the rod-shaped cells work, the amount is very large, about 120 million, 30 million. In the middle of these two is the intermediate vision, which is about 3 CDs per square meter, because the people of different Sohu.com feel Not the same, why is the intermediate vision, this is very important, now all the measuring instruments are measured according to the human eye, now LED has done a lot of street lights, now these indicators, whether mainland or Taiwan, the brightest The fast road is 1.5-2.5 per square meter, which is exactly the range of intermediate vision. According to the middle visual human eye, the measurement of different spectral energy sources, when the brightest, the human eye is 550 nm, if it is dark vision is 507 Nano is blue. What is the most sensitive light in the middle vision, we have to make measurements, so we made 1.5-2.5 when we made the street lamp standard.

If you use intermediate vision, it is best to use LED as street light. Because LED is blue light, white light and phosphor are used now. The measurement results are all in the zero vision range, because the intermediate vision has not been studied seriously. Carefully measured. Now scientifically, all the test instruments are wrong for the measurement of street lamps. This is a scientific concept. The spectral effects of intermediate vision should be re-examined. The intermediate vision instruments should also be studied. How to trim, this pair of LEDs The promotion of the city is favorable. The street lamps in each city should be bright, because the leaders of each city hope that the city will be brighter and better, and stimulate the economic growth. Therefore, the street lamps are exceeding the standard. The standard of street lamps in China is the Institute of Building Science. It is Professor Li Tienan. I asked him if this standard can be implemented. Since it was enforced on July 1 this year, I don’t think it is possible because the leaders of various cities hope that the city will become brighter and brighter. The most typical one is Beijing Chang’an Street. I hope that the lights in the evening are all in the sky, the underground is not bright enough, and two fluorescent lamps and high-pressure sodium lamps are added. Therefore, Chang'an Street is very bright, which is unscientific and is polluted by light. In 2003, a guide to limit outdoor illuminating lighting fixtures was made. The guideline is more reasonable. The city is divided into four suburbs and residences. If the commercial area and the central area can be brighter, other areas are not necessarily bright, which is good for promoting LED lighting.

The human eye is most sensitive to the yellow light of 555 nm. If it is dark vision, what is between these two curves, we have to launch an expert to test. The perception of the brightness of the human eye is related to the background light of the market, and is related to the size of the target, so the brightness of the background light determines the state of the vision. So far, no instrument can imitate the human eye. The state of adaptation, one of the human eye is to adjust the size of the pupil, and the other is to determine whether the pyramidal cell or the rod-shaped cell works. These two functions are different. If the person feels comfortable, it is a range of 100CD per square meter. It is generally super bright now, especially the light of the family, which is harmful to people's eyes. Nowadays, there are many cataracts and glaucoma, and the brightness of perception is much higher. The best brightness of people is 35-70, which exceeds this brightness. The human eye does not improve much, and the old man's eyes need bright light.

LED is not an electric light source. It does not follow the law of luminous intensity in photometry and the inverse of the distance from the bungalow. The LED lighting space must have a special light mixing and light distribution design. In-depth study of LED breadth of visual cognition, creating a more humane, personalized network super girl's health lighting system.


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