First, the concept of eye protection What is the concept of eye protection? Not sure? Then take a look at the definition of eye care for the industry!
The first is safety: the light source should be harmless to the human eye.
Secondly, it has the effect of lower eye visual fatigue, which can inhibit the induction or development of myopia. That is, according to the main causes of myopia, the design of myopia can be mainly attributed to four categories: congenital inheritance (this is no way) Change), reading habits (this can be partially corrected), light environmental effects (this can be improved by product design), excessive regulation of the human eye ciliary muscle (this needs to be solved by a combination of human eye physiological curve and intelligence).
Finally, in the case of ensuring the above requirements, the work efficiency of the person, that is, the mental load situation, is taken into consideration.
Different people have different tolerances to light. The difference between Chinese (East Mongolian ethnic group) and white people is mainly two aspects: one is the pupil diameter, which determines the amount of light entering the human eye. It is 3-5mm, white is 6-8mm; on the other hand is the pigment light tolerance of the skin, our pigment is higher than white, so our light tolerance is stronger than them. This is why many of the international standards are in fact not suitable for us. It is also the reason why we conducted more than 8,000 human eye physiology experiments. Our light requirements are very different from them.
Second, the indicators of evaluation
Long knowledge! Learn to understand the evaluation indicators used by the industry Dajia team!
We believe that the evaluation of physical indicators cannot directly evaluate the impact of products on human health. Therefore, we use the method of human factors evaluation, that is, to evaluate the light pair by the method of forming large-sample human physiological index data to form human eye physiological index evaluation model. Human influence. We have now completed the Visual Comfort (VICO) indicator, which is an indicator of the effect of light on the visual fatigue of the human eye, and the Cell Vitality Index (CV), which is an indicator of light damage to the human eye. We are currently working with CSA to draft the alliance standard, which is also a pilot for national group standards, and is working on proposals for international standards and international industry alliance standards.
At present, we believe that there is no real eye protection lamp! We have done 600 human visual tests, testing two brands including Philips, Panasonic and China, as well as the lights of Dr. Edwards, which many people talk about today. The results are not good. Including a Xiamen company manager last week said in the group to do a CCFL light, can protect the eyes, but from the CCFL light source test results, most CCFL is not as good as the high-point LED light source.
Eye protection, at least its VICO measurement should be less than 2 (slight fatigue level), but these lights are currently more than 2 values.
As mentioned above, eye protection should consider those three elements. If you don't think about it, it is very difficult to achieve this effect! LEDs provide changes to the design of the light source. This is something CCFL can't do. I think it should be needed for the lighting design of Chinese characteristics!
Figure: The figure shows a corresponding curve obtained by experiment, but in fact subjective can only be partially qualitative, not quantitative, and the fluctuation is too large.
Figure: The picture shows the human eye visual experiment conducted by the host's team in five regions in the southeast and northwest of China. It was completed in 2013, with a total of 5,000 people participating in the experiment. The conclusions obtained have been identified through scientific and technological achievements, and the conclusions are internationally leading; some of the results have been published and relevant standards are currently being drafted.
Third, group friends exchange
Listening is not enough. Only by actively participating in the discussion of the topic can you gain more!
Mainly because the light quality is not fixed, the glare has not been done well, and the illumination and ghosting are not done well! No strobe is the basis, the driver can solve the strobe.
For these views of group friends Zhang Haiwei, the host put forward different opinions:
In fact, the problem of glare I think should not be a big problem at present, after all, it is relatively mature. But is there no stroboscopic eye protection? Absolutely not, the blinking frequency of the human eye is 50-60HZ. Our experiment has determined that 100HZ is the critical point, and then the upward lifting, the visual comfort of the human eye will not change greatly, the human eye comfort (VICO) The difference is no more than 5%. The driver should be able to solve the strobe, it seems that everyone is solving this problem now!
“The main problem is the chromaticity? Which is the blue light energy control?” The group friend Lin Yidong put forward his own ideas. The host expressed his affirmation: “Yes, but the color temperature, in fact, needs to take into account the visual comfort and homework. Efficiency, illuminance, need to fully consider visual comfort and work habits. Composite white light, spectral control should be no problem!"
We mainly tested in light distribution, indexing, stroboscopic depth, glare, color temperature, blue light and ultraviolet light. There is also written comfort, eye fatigue is compared, color temperature is best from 4000 to 4500, feeling the most comfortable eyes.
For the opinion of group friend Zhang Ruijiao, the host and group friend Lin Yidong expressed doubts about this?
If your comfort is subjective, then the data itself is worth discussing. 4000-4500 is good, but it depends on the color rendering index. Under different color rendering indexes, the visual comfort curve of color temperature is different. Also consider the mental load problem, which is the efficiency of the work, so you need to consider compatibility issues.
Group friend Zhang Ruijiao's test: Say this color rendering index, I tested the LED color rendering index of 80, the cold cathode is also 80, the instrument test is no difference, but it is different with the naked eye; put a fruit or a flower or a piece The items are placed under the LED light 80 and the cold cathode display 80, and compared with the daylight, the distortion under the LED light is very powerful. Group friend Lin Yidong also pointed out that the cold cathode is the worst.
Group friend Zhang Ruijiao's test: We let 50 children of different ages use it for comparative experiment. At that time, we used the LED table lamp of Xiwannian to compare with our cold and negative lamp. Under the LED light, the concentration of the spirit will have an impact.
Simple test by group friend Jiang Chaoze: There is a light distribution design that is better than a simple sanding sheet, comfort, glare.
Group friend Shao Pengrui began to believe that the harm of purple light and blue light is comparable to a certain extent. But the moderator believes that the UV hazard is even greater, because if the blue light is really terrible, we are alive under the blue sky every day. Finally, group friend Shao Pengrui also recognized the host's point of view, blue light is impossible, because the exposure is far from reach, otherwise, traditional fluorescent energy-saving lamps have long caused a series of problems.
Ren Fei's problem with the group: The experimental results show that the peak spectrum of the blue light is in the range of 400-440 nm (nano, 1 nm = 10^-9 m), and the illuminance is within 500 lx (lux, which is the unit of illumination) for 2 hours. Above, there will be a significant decrease in cell viability and even apoptosis. The peak spectrum of blue light is in the range of 460-500 nm, and the illumination is more than 1500 lx. If the direct fluorescence is more than 3 hours, the cell viability will decrease significantly and apoptosis will occur. If you follow this theory, high-end shopping malls, some live stadiums, if you use led, will it be harmful to the eyes?
In this regard, the moderator's answer is:
The big screen itself is extremely risky. I specifically said this in the interview, and the brightness of the large screen is generally more than 800 nit. This is a great risk regardless of visual comfort or light damage angle. If we do 600nit because of the experiment, we will not go up because there is already a security risk.
In summary, in a word, LED variability is very strong, can be made into many functional products, but when it comes to eye protection, there are still many aspects that need to be broken.
