1. Heat dissipation
LED's heat resistance is poorly known by the ****, will inevitably bring the wick life of the problem. Existing LED lamp design is often difficult to meet the requirements of heat dissipation, in a very demanding field of heat dissipation, but the use of very poor passive cooling methods, and more air-cooled, or even closed air-cooled. Like some lamps in the drive plate and aluminum heat sinks to add plastic sleeves to increase the reliability of insulation, but also need to pour heat dissipation silicone to improve heat dissipation capacity. The T8 lamp lamp or closed, the wick can only rely on air convection heat transfer to the back of the lamp on the aluminum tube for heat dissipation. Generally the internal temperature of these lamps will be seventy to eighty degrees. And if you take into account the heat, the weight is a problem; take into account the weight, the heat is difficult to ensure that this is a dilemma in the existing design, there is no feasible standard.
2. Life
LED wick life with the temperature increases and exponential reduction; electrolytic capacitor temperature rises every ten degrees life reduced by half; MOS temperature rises, the internal resistance increases, the loss increases, the temperature rises (constant current mode), and ultimately burned. Of course, the domestic manufacturers did not give specific LED lamps and lanterns life, publicity, just mention the LED wick life of 100,000 hours, but the LED life bottleneck in the system driver board, often the LED wick is not damaged, the system driver has been hung up.
In addition, the LED light decay is very serious, so the life of the lamps should also consider the visual experience, that is, after a long time the brightness of the lamps and lanterns reduced to the degree of visually feel the darkness, you can think of the life of the lamps and lanterns, customers will consider replacing the lamps and lanterns, the life of the manufacturers have not been given out (or there is no way to give), but this is very important.
Then again, the existing LED home lighting Most of the volume limitations, protection is difficult to do a good job, in the voltage fluctuations, interference in the region, the existing low-power design is a test.
And most importantly, the life of the LED and the company's life is proportional to whether, if the promotion of 10 years of LED lamps and lanterns 2 years on the bad, and six months ago the company has closed down, the user will go to take the risk?
3. Weight
The weight of fluorescent lamps is only a fraction of that of LED lamps and lanterns in spiral interface lamps and lanterns, and the weight of fluorescent lamps is negligible for lamp holders due to the absence of heat sinks, but the weight of LEDs is a serious test for lamp holders, especially 7.8W spiral interface LED lamps, whose weight is dangerous, which is also taken into consideration by which businessmen? Which businessman has considered?
4. Price
General LED driver board in 70 degrees temperature may be only 5 years of life (household), far from the LED wick 10 years of the "concept". So compared to the same brightness of fluorescent lamps, even if the fluorescent lamps only 1 year life, 1W1 yuan fluorescent lamps are far more cost-effective than 1W10 yuan LED. Especially LED lamps and lanterns are often damaged wick is not bad, but to replace the entire lamp. Do the math because one-tenth of the driver board but to discard the remaining nine-tenths of the lamp (wick and heat sink accounted for the vast majority of the cost of the entire lamp), if every manufacturer does not do a good job of recycling, customers will not like this product.
Correct use of regular LED lights does not hurt the eyes
According to a recent report in the UK's Daily Mail, the results of a recent study in Spain suggest that LED energy-saving lamps have the potential to damage people's eyesight. Research experts believe that table lamps and other lights used in close proximity should try not to use LE D bulbs. When the news came out, opinions were divided. Part of the netizens immediately said that will no longer use LED desk lamps, but there are many people spoke out against, that this statement has "indiscriminate LED a stick to death" suspicion, the report can only be aimed at the "three poor quality LED". By the industry generally optimistic about the LED lights, in the end there is no damage to the retina of the hidden dangers? To listen to ophthalmologists and lighting experts to analyze.
Ophthalmologist point of view
More blue light, brightness, may hurt the eyes
Zhongshan Ophthalmic Center, Sun Yat-sen University, senior optometrist, optometry expert Lu Jinhua said, different wavelengths of light, penetration is not the same. Light that is harmful to the eyes is dominated by high-energy short-wave light, such as ultraviolet, blue and violet light, and the human eye feels most comfortable with medium-wave green light. Blue-violet light is more penetrating than short-wave ultraviolet light, and has relatively high energy in the visible spectrum, which can penetrate the cornea and lens and reach the retina, which will cause irreversible damage once it is damaged. Therefore, the greatest damage to the human eye in nature is the short- and medium-wave, relatively high energy ultraviolet and blue violet light.
The general LED light emitting, light color single, high brightness, high color temperature, may contain more blue light components. "For a cell, if it receives high-energy photons, it may produce some damage to its nucleic acids and proteins, so that the whole cell is fatally threatened."
"I think the study by this Spanish expert, which mentions that LED damage to the eyes is mainly for the fact that it has more blue light content in it, which may cause irreparable damage to the retina after a long time. This may have some truth."
Lu Jinhua believes that the LED lights, in two aspects may be harmful, the first is the blue light content is more, harming the retina; the second is that some of the products are too bright, will stimulate the human eye to constantly adjust, resulting in eyestrain.
In addition, LED has the potential to form glare. Glare refers to the local brightness is too high, disproportionate to the surrounding environment, so that the retina produces bright areas and dark areas, resulting in drastic changes in the pupil. Glare can cause problems such as eye soreness and swelling. If both the glare phenomenon and the adjustment stimulus are large, it can have a negative impact on the vision of the human eye. If a long period of time in the blue light hazards, glare phenomenon, will increase the importance of fatigue, damage to the optic nerve, especially on the vision of the temporary vision has not yet stabilized the negative impact on the vision of young people.
Lu Jinhua also emphasized that, on the other hand, LED lights energy saving and environmental protection, is the most promising kind of light source, "we can not because of the current level of technology, some poor quality products to negate it, we also need to recognize that there are some of the better quality LED, and in the future there will be continuous process improvements, such as making the color temperature more moderate, reduce the content of blue light, brightness of the LED. The content of blue light, the brightness of the design is more reasonable, etc."
Foreign expert opinion
Long-term use of LEDs may damage the retina
According to the British newspaper "Daily Mail" reported, Spain, Madrid Complutense University (Com plutenseU ni-versityinM adrid) of Dr. Celia-Cassans-Ram os (CeliaSánchez-Ram os) The study shows that because the light emitted by LEDs is a short-wave, high-energy light source, blue and violet in the visible spectrum, prolonged exposure to this light may cause damage to people's retinas.
Dr. Kassans-Remmons also pointed out that the light radiation emitted by energy-saving lamps can cause serious damage to human retinal pigment epithelial cells. For this reason he recommends that table lamps and other lights used in close proximity try not to use LED bulbs. Try not to look directly at the light source with your eyes, and pay attention to the use of time, every 20-30 minutes to close your eyes and rest for a while.
Tips: good desk lamp nine standards
Color temperature, brightness is an important criterion for judging the merits of a desk lamp, but only these two indicators are far from enough. Let's say, even if the color temperature is right, if the use method is incorrect, it may also lead to injuries. Earlier, a baby in Xi'an was blinded because of the long-term use of the bath light, and this case is enough to sound the alarm for us. The color temperature of the bath bomb is not high, but the power is extremely high, and babies face upwards when bathing, directly facing the light source. Even if the content of blue light in the light of the bath bomb is very low, but the superposition of the combined factors, it will still produce a serious blue light hazard, and ultimately cause permanent damage to the retina.
Xu Qinghui that a good desk lamp, must stand up to these nine standards:
1, look at the certification: learning desk lamps must be through the national mandatory C C C certification, and in the validity period;
2, look at the color of light: color temperature of 3200 ~ 3500K warm white light source is most in line with the visual physiological needs of the human eye;
3, look at the glare: the eyes from the desktop Height 40 cm, from the desktop lamp light source at a horizontal distance of 60 cm, you should not see the lamp within the direct or refracted light;
4, look at the illumination: light source from the desktop height of 4 0 cm at the illuminance in the 750- 1000 Lx for the best visual light environment; no instrument? That can only be felt visually, the desktop should be "very bright" feeling is right;
5, look at the color: palm up on the desktop lamp under the 30 cm, palm lines clear, skin color rosy, the desktop light color is clear, the color reproduction is good; on the contrary, fuzzy, yellowish color, grayish white is poor;
6, look at the Power: LE D lamps should be more than 7W, energy-saving lamps should be more than 11W, tungsten halogen lamps (quartz lamps) should be about 35W (desk lamps work for a short time, energy-saving is not a major consideration);
7, look at the stroboscopic flicker: low-frequency flickering can cause eye fatigue. Use your cell phone camera to look at the light, there are stripes of certain stroboscopic, but there is no stripe is not necessarily no;
8, look at the structure: desk lamp bracket to have a certain length, easy to stretch the contraction, suitable for computer operation, drawing calligraphy, learning to play the piano and other multi-purpose use.
9, look at the range: learning desk lamp should be a certain height, when the light irradiation surface, light uniformity, 40 centimeters away from the desktop illuminance should not be less than 750 Lx;
Lighting light source experts to clarify
Blue light ≠ blue light hazard
Guangzhou City, Kobelco Lighting Engineering and Design Company Limited Design Director, Senior Lighting Designer Xu Qinghui told Nandu reporter, "Blue light ≠ blue light hazard
The blue light ≠ blue light hazard
Guangzhou City, Kobelco Lighting Engineering and Design Co. Ltd. design director, senior lighting designer Xu Qinghui told the reporter, "blue light hazard" is only a noun, not "blue light = hazard". Reasonable use, quantitative assessment, qualified LED can be used without fear.
Xu Qinghui explained, "LED to emit white light, you need to send blue light, and then excitation phosphor, yellow light, cross into white light. Color temperature is formed by the two waves of different heights, if it is a cold color, very white light, blue light component is a little more, a little less yellow light, which is a high color temperature, otherwise it is a low color temperature. When people found that the high color temperature of LE D light in blue light here has a very high peak, just coincides with the location of this peak of blue light hazard, so it is considered that the high color temperature of the LED in the blue light hazard is a risk. This statement is correct. But it is not that the high color temperature of the LED on the human eye is necessarily damaging, only that it is more likely.
Moderate amount of blue light can regulate human physiological rhythms
In the seventh Shanghai International New Light Source & New Energy Lighting Forum, the participating experts also reached such a **** knowledge, blue light is the basic component of white light. With daylight and traditional light sources, white light LE D also contains blue light. The right amount of blue light is not only necessary to ensure that the color rendering performance of the light source, but also on the human physiological rhythms have a regulatory role.
The damage to the retina caused by blue light is mainly due to excess radiation at wavelengths of 400-500 nanometers. The data obtained from various light sources and daylight spectral calculations, as well as the measurement results of authoritative laboratories at home and abroad, show that the blue light content of white LE D light sources is not higher than that of traditional light sources such as fluorescent lamps and metal halide lamps, and daylight under the same color temperature; the amount of blue light irradiation in the retina of the human eye from white LE D light sources is similar to that from traditional light sources such as fluorescent lamps and metal halide lamps, and it belongs to the category of 0 and 1 of the safety of the lighting products.
The correct use of qualified LED does not hurt the eyes
According to the EU issued for laser products (including LED) test standard IE C / E N 62471, as well as China's national standard G B / T20145-2006 lamps and lamp system photobiological safety, blue light retinal hazards can be categorized into four: no danger, low risk (Category 1), medium risk (Category 2), high risk (Category 3), high risk (Category 4), and low risk (Category 5), and high risk (Category 6). and High Hazard (Category 3). According to the relevant international regulations, if the manufacturer provides a statement indicating that the irradiance of the luminaire belongs to the non-hazardous category or low-hazard (category 1), the certification body can accept such an LED luminaire and consider that it will not produce photobiological hazards under normal circumstances. If the luminaire's irradiance belongs to category 2 or 3, it cannot be used directly without a warning label.
In May 13 held the seventh Shanghai International New Light Source & New Energy Lighting Forum, experts from academia, industry, medical experts reached a basic *** knowledge, the main conclusion is that the correct use of qualified general lighting white LED products, for the human eye is completely safe.