LED emission. Are LED lamps harmful to health? Reviews from experts

Ideally, a spectrophotometer is needed to assess the quality of the lamp's emission spectrum. IN as a last resort you can use spectrophotometers for profiling/calibrating monitors (for example, ColorMunki) - if you have such a device. There is no point in buying spectrophotometers at home to evaluate lamps; they cost from hundreds to tens of thousands of dollars.

Nevertheless, for the needs of geologists and jewelers, simple spectroscopes based on a diffraction grating are produced. Their cost is from 1200 to 2500 rubles. And it's a fun and useful thing.

The spectroscope looks like this:

You need to look into the eyepiece (on the left, where the cone is), while the lens (on the right) should be directed towards the radiation source.

A diffraction grating splits light into a spectrum (like a rainbow or an optical prism).

Before delving into the spectra of real lamps, let me remind you general information. (This is discussed in some detail in the book in the chapter “Quality of Light”).

Here I will show two SDL spectra with an exceptionally high color rendering index of 97:

Cold light:

You can see that the color temperature is 5401 K, index 97. The main thing is that you can see from which visible to the eyes There is a spectrum of colors.

Warm light:

Temperature 3046 K, index also 97.

A spectrophotometer - unlike a spectroscope - shows not just which colors form the spectrum, but also gives their intensity. It is clearly visible that in the spectra of both lamps there are all the colors that make up white (“every hunter wants to know where the pheasant sits,” i.e. red, orange, yellow, green, blue, indigo, violet). The difference in color temperature is achieved through the relative contributions of cool (blue-cyan) and warm (yellow-red) components.

I am forced to mention that this spectroscope is intended for mobile use using the eyes. It is extremely inconvenient to fix the image, since the eyepiece is small and there are no devices for fixation on the camera. Therefore, you need to hold the camera with one hand, the spectroscope with the other, and control the shooting with your voice. At the same time, you still need to keep the direction towards the light source; small deviations from the normal lead to distortion of the colors of the spectrum. Of the almost dozen different cameras that I have at home, the Samsung tablet turned out to be the best. The camera there is only 5 megapixels, but good software, and the size and position of the lens on the device body allows you to more or less conveniently attach the spectroscope. White balance was fixed as “daylight”, ISO 400. The pictures were not processed, only straightened and cropped. The numbers on the right indicate the color rendering index of the source (100 - daylight in cloudy weather, 99 - incandescent lamp). I'm not very happy with the quality of the photos - but I couldn't take it better.

So let's start from top to bottom and specific examples Let's try to understand what you need to pay attention to in such spectra.

Daylight and incandescent: an ideal spectrum that includes all of the above colors.

SDLs with color rendering indices of 87 and 84 also demonstrate almost a full range of. The problem is usually the red part - while yellow and orange are usually sufficient, deep red shades are most often absent. They are not visible here either. It can also be assumed (for example, by the amount of blue in the spectra) that manufacturers use different 5736SMD LEDs. Those. We are not dealing with the same lamp purchased from different sellers - but with different manufacturers.

SDL with index 78 (its analysis is given in the chapter “Example of assessment testing” in the book) along with the trimmed red part also demonstrates a small amount of blue. (It may seem that in comparison with the spectrum of a lamp with index 84, this is not the case. But here you need to remember that 84 is a warm lamp, T = 2900. And 78 is cold, T = 5750 K, there is, by definition, much more blue) . This is precisely the main disadvantage of simple budget SDLs, which produce supposedly white light due to the blue or purple radiation of the LED and the yellow-orange light of the phosphor. To the right of blue lies blue - but from the described combination it “does not work.” Therefore, there is usually a dip there in the SDL spectrum. Due to this (plus a deficiency of deep red) the color rendering index drops.

The lowest spectrum is a high-quality compact fluorescent lamp (CFL, T=2700 K, resource 12,000 hours, declared color rendering index of at least 80). And here you can clearly see how this formally rather high value is achieved. The manufacturer itself calls this the “Tricolor system”. Those. it uses a phosphor of 3 components, each of which emits light in a narrow band. (Of course, it is not at all easy to make such a lamp, since a careful selection of the combination of phosphors is required.) It is the presence of such vertical stripes (for example, violet, green, yellow) that is a sign of low-quality light sources. The second consequence of the line spectrum of the source is the physical absence of some colors in principle (in the figure, for example, there is practically no yellow and very little blue). It is obvious that the light of such lamps is of little use to the eyes, despite the formally quite high performance. Such lamps should be used in lamps with high-quality diffusers (although, of course, this will not change the spectrum of the lamp).

Conclusion: in the spectra of light sources with a high color rendering index, all colors of the spectrum should be present and there should be no intense narrow bands.

Separately, I would like to warn against haste in analyzing the spectra. In my line of work, I talked a lot with spectroscopists and noticed an ironclad pattern: the more qualified and professional the specialist, the more cautious and evasive he is in his conclusions. From the best of them, the professor, head of the spectroscopy laboratory, it was generally impossible to achieve a clear conclusion (which at first, when I was young, irritated me wildly). The eye is by far the best optical instrument from existing ones. But the analysis and interpretation of spectra is an endlessly complex topic. There are a huge number of various factors. Therefore, I strongly recommend only the simplest qualitative assessment of spectra with the eyes, without attempts at cunning reasoning and far-reaching conclusions. It is best to alternately look at the spectrum of the lamp being evaluated and at the ideal spectrum of daylight or FL. Those. clear comparison with each other. published

Until recently, diode-based lamps were a rarity in our homes. Just five years ago, energy-saving products were advertised everywhere fluorescent lamps which seemed very good option lighting to save energy and replace incandescent lamps in everyday life and at work. Even programs for transition to energy saving lighting, and on a national scale. To the point that incandescent lamps were about to be banned. I remember around 2011, one of the TV shows showed different kinds energy-saving lamps for the home and were shown, among other things, diode lamps. But their manufacturers explained that such lamps, although environmentally friendly, are low-power and very expensive, and are unlikely to be able to compete with fluorescent lamps in the next decade energy saving lamps at home.

Life has refuted this forecast. The rapid progress in LED lighting is truly amazing. The power of lamps is increasing, the cost is decreasing. Now an 11 W light bulb (equivalent to a 75 W incandescent lamp) can be bought for 100 - 150 rubles. At the same time, the service life declared for the lamp is 50,000 hours. The lamps have become indistinguishable in shape from conventional incandescent lamps; the white light can be cold and warm shade. This new lighting fixture is now found in almost every home.

But, like all new devices, the LED lamp raises questions and caution. Will it cause harm to health and vision? What shortcomings might the manufacturer be hiding in an attempt to make a profit? We have already published a number of articles on our website about new devices (Is it harmful to heat food in the microwave? The harm and benefits of an infrared heater. The harm and benefits of an induction cooker.) Now it’s the turn of a household LED lamp.

First of all, a little explanation about the operating principle of an LED lamp. The international name is LED lamps(light-emitting diode). A standard light-emitting diode contains three layers of semiconductor materials. Electrical voltage causes electrons from the anode (n-layer) and holes from the electrode (p-layer) to move into the intermediate layer, where they recombine to emit photons. The intermediate layer is a special crystal with a certain band gap. The width of this zone, as well as impurities in the crystal, determine the color of the radiation. In the early 1960s, the first industrial samples of LEDs based on gallium phosphoride and arsenide were created, emitting red light, and then green. Even then, these devices were more efficient than conventional incandescent lamps. They were used as various color indicators. However, it took a long time to obtain a cheap and bright blue LED. And without adding of blue color It is known that it is impossible to obtain the white light needed to illuminate houses.

No wonder that Nobel Prize in physics in 2014 was awarded to Japanese scientists Isamu Akasaki, Hiroshi Amano and Shuji Nakamura for the development of “fundamentally new environmentally friendly light sources,” namely for the invention of blue LEDs, which, in combination with red and green ones, can give a wonderful white light source. The main difficulty in inventing the blue LED was finding a good crystal for the intermediate layer. For it to emit blue light, a material with a large bandgap is required. A solution was found when it was proposed to use an LED with a gallium nitride (GaN) crystal on a sapphire substrate. The intermediate layer was subjected to special heat treatment and received impurities not only of magnesium, but also of zinc, and then of indium. Although the invention of Japanese scientists was made back in the mid-90s of the 20th century, its practical significance was appreciated and began to be widely used in the 21st century. In 2001, the possibility of using a quartz substrate in an LED, instead of a sapphire one, was first proven, which opened the way for the production of cheaper lamps.

Nowadays many companies produce household LED bulbs and lamps. The largest producers LEDs in Russia and Eastern Europe are the companies "Optogan" and "Svetlana-Optoelectronics" (St. Petersburg).

Let's first consider the advantages of such lamps. There are not so few of them and they are quite convincing.

High luminous efficiency reaching 146 lumens per watt.
High mechanical strength, vibration resistance (no filament, brittle glass)
Long service life - from 30,000 to 100,000 hours (when working 8 hours a day - 34 years). Lamp life is highly dependent on temperature. When operating at temperatures above room temperature, the service life is reduced.
Low inertia - they turn on immediately at full brightness, while mercury-phosphorus (fluorescent-economical) lamps have a turn-on time of 1 s to 1 min, and the brightness increases from 30% to 100% in 3-10 minutes, depending on ambient temperature.
The number of on-off cycles does not have a significant impact on the service life of LEDs (unlike traditional light sources - incandescent lamps, gas-discharge lamps). Safety - no high voltage required, low LED or fixture temperature, usually no higher than 60 °C.
Insensitivity to low and very low temperatures. However, high temperatures LEDs are contraindicated, as are any semiconductors.
Environmentally friendly - no mercury or phosphorus inside the lamp.

Technology is constantly being improved to make lamps more environmentally friendly and beneficial to our eyes. However, as with other appliances, there are cheap and expensive options. Manufacturers sometimes do not indicate all the characteristics on the box. Let's take a brief look at what problems people may have when using LED lamps.

1. This is, first of all, the radiation spectrum. In 2013, information about the dangers of LED lighting spread across the Internet, citing a study by Spanish scientists from the Complutense University, which showed that the light emitted by LED lamps can significantly damage the retina of the human eye. Moreover, these damages can be so severe that no medications or surgical procedures can help. Sometimes there are notes that supposedly the spectrum of LED lamps contains a hard blue and even ultraviolet component, which is harmful to our eyes. Indeed, there are sanitary standards UV irradiation of the retina, which is recommended not to be exceeded. Note that the strongest source of UV radiation is the Sun. All experiments to confirm the harmfulness of UV radiation were carried out on animals and bad influence on the retina was noted only during prolonged irradiation with very bright light.

The following figure shows the spectrum of four lamps - one incandescent lamp and three LED lamps. The figure is taken from a 2011 publication on the website http://geektimes.ru/post/253792/.

The lowest peak of the spectrum curve is in the range of 400-500 nm. - at the Optogan lamp. Therefore, this lamp has the lowest color temperature, it is equal to 3050 ° C. (It’s interesting that the cost of such a lamp in 2011 was 995 rubles!) As we have already said, enormous progress has been achieved. Now most household lighting lamps have a color temperature of 2700-3000 K, which is far from the UV region. And yet, when choosing a lamp in a store, pay attention to its color temperature. This parameter is always on the box.

As for the conclusions made by Spanish scientists, they relate to the radiation of all kinds of LED screens, such as the displays of all kinds of gadgets, computers, televisions, etc. Scientists have proven that if you look at such screens for a long time, without any eye protection, this can actually lead to gradual changes in the retina. Therefore, it is recommended to protect your eyes when working with a computer for a long time with special glasses. Take frequent breaks. On lighting We don’t look long and hard, so there’s no harm from them.

2. Light flickering. The flickering frequency of the lamp depends on the operating principle and design. Flickering light can have a negative impact on health, so there are sanitary standards here too. Ripple luminous flux(amplitude of brightness fluctuations) in the living room or in the work room office space should not be more than 20%. Light pulsations are very characteristic of old fluorescent lamps. For good LEDs they are minimal - less than 1%. Although there are cheaper lamps with ripples of more than 60%. This parameter is usually not indicated in the description on the box with the lamp. I can advise you to just buy not the cheapest ones modern lamps. In them, power is supplied through special drivers, and not through capacitors. There are tips on the Internet on how to independently evaluate light pulsations. It is suggested to look at the lamp through a mobile phone camera.

3. Another problem associated with the spectrum of a diode lamp, which is sometimes mentioned on the Internet - the harm of bright white on human health. What is meant is not the effect on vision, but the effect on nervous system, suppression of the production of the sleep hormone - melatonin. It is recommended in the evening, a couple of hours before bedtime, to reduce the brightness of the lamps, use more warm light. Unlike fluorescent lamps, some LED lamps, like incandescent lamps, support the function of dimming using power controls “dimmers”, this should be indicated by the manufacturer on the packaging.

4. Insect problem. They love bright light, and they are less attracted to incandescent lamps than diode lamps, including because of their strong heating. LED lamps, which brighter than lamps incandescent and do not heat up, sometimes they gather clouds of flying insects around them. This problem is especially relevant when lighting large southern cities, where sometimes there is an “invasion” of various mosquitoes, flies, and cicadas.

The LED lamp is one of the most necessary and important inventions of our time. It not only improves the quality of light in our homes, but also helps solve the problem of energy conservation - one of the most current problems on the ground.

Nowadays, LED lamps are no longer uncommon in stores and their prices are quite low. But how to choose the right lamp? What are the main parameters by which they need to be compared? Why do we think the lamps we offer are better than most lamps you will find in the store?

First, let's list the main characteristics of lamps and figure out what they affect in actual operation.

Nutrition

The bulk of LED lamps on the market require 220V power to operate. This means that the lamp has a built-in power supply that converts 220V voltage into current to operate the LEDs, since the LED does not require constant voltage to operate, namely D.C.. If you don’t understand this, it doesn’t matter, the main thing is that you know that the power supply in the lamp is a very vulnerable unit. The problem with it is that it is very small and can get very hot, and the heating comes both from the power supply itself and from the LED. If the power supply is of poor quality, the use of cheap components, not a very good circuit, poor heat dissipation, low-efficiency LED, the power supply fails in a relatively short term. It cannot be replaced. The usual story: bought Chinese lamp, worked for six months, burned out. It was not the LED that burned out; this happens very rarely. It was the power supply that burned out. Even when turned on, our lamps can be held in the hand Small child and don’t complain about the “hoyach”.

There are also lamps for 12V power supply. You may think that you can use them without problems with a regular transformer for halogen lamps, but this is not the case. The fact is that transformers for halogen lamps require a minimum load in order to work correctly, otherwise they either do not turn on at all or make terrible sounds. LED lamps are too low wattage to provide this minimum load. To power 12V LED lamps, special power supplies are required. That is why we do not offer such lamps.

There are also specialized lamps that do not have a built-in power supply and must be connected to a special LED driver. This is a professional solution that provides a very long lamp life, excellent lamp control and saves space behind the ceiling. At the same time, the lamp itself is cheaper (since there is no power supply). We plan to offer this option soon.

Cooling radiator

The main weight of the LED lamp falls on the cooling radiator. It is extremely important for the normal and long-lasting operation of the lamp. If it is too small, incorrectly made or has poor contact with the LED, then such a lamp will fail within 6-12 months.

Light-emitting diode

LED is the light-emitting element of a lamp. Nowadays, several arrangements of LEDs in lamps are used: several white LEDs, several white SMD LEDs, one heavy-duty white LED, one or more blue LEDs coated with phosphor, which converts blue light to white. Our lamps use the latest layout. It allows you to obtain a good continuous spectrum of radiation, as well as easily vary the color temperature. In addition, the blue LED used has more high efficiency and durability than the cheap white LEDs commonly used in lamps. Roughly speaking, the first two layouts immediately indicate a frivolous product.

Colorful temperature

Color temperature is the shade of white as a person perceives it. The first LED lamps became famous for their bluish tint. Their color temperature was around 6,000 Kelvin, which is the hue of the sun's light on a bright summer afternoon. On the street it is perceived as normal against the background blue sky, but it is not suitable for indoors. Most of Chinese cheap lamps have a color temperature in this area. An ordinary incandescent lamp has a color temperature of around 2600K (the light of the sun is closer to sunset). But many people find this light too yellow and depressing, especially in winter. Therefore, we offer lamps with temperatures in the range of 2600-3200K (warm white) and 3700-4200K (natural white). The scatter is due to production technology, but you won’t be able to tell it apart by eye.

Emission spectrum

White light is made up of blue, green and red colors. More precisely, from an infinite variety of light frequencies (colors) from blue to red. We all exist under the Sun and all our processes and organs are adapted to the solar spectrum of light. Therefore, the more similar the spectrum of the lamp is to the spectrum of the sun, the more correct colors you perceive. The spectrum of cheap lamps can be discontinuous (large peaks on certain colors with dips in between) or skewed in one direction. Our lamps, thanks to phosphorus, have a continuous spectrum close to that of the sun. Plants will grow well under our lamps and can even be used to illuminate an aquarium.

Color quality

Color rendering quality determines how accurate the colors will be in the lighting. It is clear that if the lamp is red, then all the colors in the room will be distorted. The correctness of the spectrum determines how correct you will see the colors. As a rule, cheap lamps have a spectrum very different from natural light. Color rendering is determined in CRI (color rendering index) units and can range from 0 to 100. For halogen lamps it is always 100. In this area, no one can surpass them, since their emission spectrum coincides with the sun. Old fluorescent lamps and older or cheaper LED bulbs have a CRI of around 60 or even less. Today's most expensive LED and fluorescent lamps have a CRI of 90+. Our lamps have a CRI from 70+ to 80+, which provides a normal level of color rendering, at which you need to have a special table in front of your eyes to find the difference. The difference of 5 CRI units is not visible to the eye at all.

Lifespan

The lifespan of the lamp is important to the buyer as an economic parameter. It is clear that LED lamps are much more expensive than conventional incandescent lamps. By purchasing such a lamp, you hope to save money on electricity bills in the future. There are two main parameters that influence the actual (to write many) lifespan of the lamp: the quality of the power supply and the quality of cooling. A lamp that is too cheap may not have high-quality components in the power supply or a sufficiently massive, but aesthetically pleasing, heatsink, so do not expect a long life from it. Also note that claims of 60,000-100,000 hours should not be taken seriously. Nonsense. 60,000 hours is 7 years of continuous work, i.e. 14 years of actual use. If you look back 14 years at LEDs, you can see how much progress has been made. And after 5-6 years from now on, you will simply have a desire to change your lamps to more economical, brighter ones with better color rendition than those that exist now. And it will be economically justified. Technologies are developing too quickly to plan 10 years ahead.

In addition, in order to write such an operating time, the power supply must be certified according to all the rules for such a service life. Of course, manufacturers cannot conduct tests for 7 years. 7 years ago these LEDs did not exist. According to the testing rules, they make a test batch of 2000 pieces, turn it on and find out that after 1000 hours, out of 2000 pieces, for example, 2 pieces failed. From this data they extrapolate the mean time between failures. This allows you to calculate the cost of the warranty, but it has no relation to the real life time. This test does not take into account the effects of avalanche-like aging after a certain period of time; different conditions operation.

Look at how long the manufacturer's warranty is. If it says 40,000 hours and a 1-year warranty, then it’s a laugh, and that’s all. The lifespan of our lamps is 20,000 hours and the warranty is 2 years, i.e. Almost the entire service life is covered by a guarantee with 24-hour operation. This is a criterion for confidence in the quality of your products.

Light cone angle

For classic pear-shaped lamps, this parameter is not relevant, since the light diverged into a sphere evenly in all directions. However, an LED only emits light in one direction and must either be diffused or collected. Lamps with E27/E14 sockets provide uniform light dispersion. Some light is lost in this process, but only a little. We tested all the proposed lamps; the diffusion is very uniform, the glow is bright and uniform.

For spotlights The wider the angle, the more uniform the lighting in the room. Regular cheap lamps have an angle of about 15-30 degrees. The same is true for halogens. This is done because the intensity of the LEDs is not sufficient to give good light on a wide cone. Such a narrow cone illuminates a small circle brightly on the floor, and in order to create normal lighting you need to place a lot of them and densely. Our spotlights have an angle of 60 degrees, like the best halogen lamps. This makes it easy to create uniform lighting in room.

Brightness

Brightness is the amount of light that a lamp produces over its entire surface. Measured in lumens. Our lamps are good because if they are placed in place of conventional or halogen lamps, they will create illumination at least as good as it was (usually much better), while reducing energy costs significantly.

Power and efficiency

Lamp power is the amount of energy that a lamp consumes to create its luminous flux. And efficiency is the amount of energy consumed (watts) per lumen of light output. Knowing the power will allow you to calculate your electricity costs. And knowing the efficiency allows you to compare lamps and choose the best one, of course, taking into account other parameters.

Degradation rate

Unfortunately, LEDs have their own fly in the ointment. They do not burn out, but they gradually lose their brightness due to quantum processes inside the diode and phosphorus itself. Degradation rate is very important parameter. It may turn out that after a year the lamp will lose more than half of its brightness. Cheap LEDs either do not test for this parameter at all, or it is so bad that it is not shown to anyone. Our lamps have a degradation rate of 70% at the end of their service life. However, tests of compact fluorescent lamps, popularly known as “energy savers,” show that they also suffer from this problem. After a year, their luminosity drops by 20-25%.

Now you know all the main characteristics of LED lamps.

How to choose the right LED lamp? Yes, just ask for these characteristics for the lamps you are interested in. If they give them to you (which is doubtful), then you can objectively compare the lamps and understand which one is right for you. And if they are not given, then this is definitely not an option for purchase; you will only lose money.

Greetings, my dear readers! There are a huge number of articles online discussing the benefits LED lighting. Indeed, LED lamps seem to be the most promising method of artificial indoor lighting, given the mercury content and light quality problems of energy-saving mercury-containing lamps, which are now at the peak of popularity. LEDs use significantly less energy than even compact fluorescent lamps (CFLs) and do not contain mercury. And they are gradually becoming more cost-competitive with CFLs at the point of purchase. Everything seems to be great... But do we all know about this lighting, are manufacturers hiding the harm of LED lamps? Let's figure it out.

The first LED was created back in 1927 Oleg Vladimirovich Losev (1903-1942), however, LEDs did not become commercially available until 1962 (then red LEDs with a wavelength of 650 nm appeared). In the 70s green, orange, and infrared LEDs appeared. In 1993, Shuji Nakamura received the first blue LEDs. These cheap LEDs were based on a compound of gallium nitride and indium nitride. The invention of Shuji Nakamura paved the way for the subsequent development of white LEDs obtained from blue LEDs using phosphor coating.

White LEDs are used for lighting purposes. This lighting has undoubted advantages associated with low energy consumption, virtually no heating during operation, short start-up time and long service life. Many predict that incandescent lamps will be completely replaced by LED lamps. However, LED lamps have not only positive sides, but also negative, and you need to know about this, since it is very important for our health.

Harm from LED lamps to vision

As studies show, the main disadvantage of LEDs used in lighting is the high intensity of short-wave radiation with high energy blue and violet spectra, which are harmful to the visual system .

Experiments carried out by Spanish scientists, the results of which were published in an industry journal Seguridad y Medio Ambiente, show that LED lamps can cause irreparable damage to the retina of the human eye. It has been scientifically proven that blue light has a negative effect on the retina of the eye. The injuries produced by such radiation are traditionally classified into three types: photomechanical (the effect of a shock wave of light), photothermal (caused by a local increase in temperature) and photochemical (changes in the structure of macromolecules).

Retinal pigment epithelial cells have important in the functioning of the visual system and their disruption can lead to vision problems and even blindness. In the experiment, scientists grew retinal pigment epithelial cells from healthy donors in a nutrient medium, which was replaced every 24 hours to prevent evaporation. Some of the cells were exposed to various sources light on a 12-hour light/12-hour dark cycle, others were not exposed to light. After irradiation, the cells were processed and the number of dead cells was determined using special techniques. When exposed to LED lighting, the number of dead cells increased, and the growth of new cells was also suppressed. Blue light caused a very significant decrease in cell number, although green and white light also had high phototoxicity. Red light did not have such a significant effect. However, using lighting in which the red spectrum predominates all day is also wrong. Short-wave radiation of the blue spectrum contributes to more productive work and concentration, so in work areas it is more correct to use lamps or systems in which this spectrum is present.

You also need to understand that there is no artificial lighting cannot replace natural sunlight. Located outside in bright light sunlight important for everyone - both adults and children. According to research by endocrinologist Alan Christianson, to balance cortisol levels, adults should walk outside in daylight for at least 20-30 minutes. in a day. Children, in order to reduce their risk, need to be outside for at least 2-3 hours a day.

Classification of lighting according to risk level

Standard EN 62471 classifies light sources according to their phototoxicity (from ultraviolet to infrared radiation). The standard identifies 4 risk groups, in accordance with the maximum permissible exposure time:

0 risk(no risk). When the maximum exposure time is more than 10,000 sec.
1 risk group(low risk). When the maximum exposure time is from 100 to 10,000 sec.
Risk group 2(moderate risk). When the maximum exposure time is from 0.25 to 100 sec.
3 risk group(high risk). When the maximum exposure time is from 0.25 sec.

Based on this standard, researcher Behar-Cohen determined that blue LED with an intensity of more than 15 W belongs to risk group 3; if the light intensity is 0.07 W, then it belongs to risk group 1. LED lighting for everyday use classified by him as risk group 2 (compared to traditional lighting sources, which belong to group 0 or 1). He also found that the amount of blue spectrum emission from white LEDs was 20% higher than in daylight the same color temperature.

LED lamps and melatonin

Despite obvious advantages LED lamps, many scientists It is recommended to avoid LED lighting, especially in the dark before bedtime.

Study after study has found links between nighttime light exposure and cancer (breast, prostate), diabetes, heart disease and obesity. Light suppresses the secretion of melatonin, a hormone that affects the day-night cycle. But lighting is only "dangerous" if we are exposed to it at a time when we should be in the dark, and if the exposure is sufficiently intense and long-lasting, says physicist Fabio Falchi. While light of any spectrum can suppress melatonin secretion, blue light does this to a greater extent. That's why Scientists recommend relying more on incandescent lighting after dark, especially in the bedroom.

Also, in order not to disturb the day and night routine, it is recommended:

use dim lighting red spectrum;
do not look at a bright screen 2-3 hours before bedtime;
when working at night with large quantities electronic devices wear special glasses that block the blue spectrum.

Harm of LED lamps to the environment

A study published at the end of 2010 in the journal Environmental Science and Technology suggests that LED lamps are also harmful to the environment. Scientists have discovered that in some types of LEDs used in New Year's garlands, traffic lights, car headlights and brake lights contain lead, arsenic and a dozen other potentially dangerous substances.

One of the scientists who conducted the study, Oladele Ogunseitan, says that while inhaling fumes from a broken LED is unlikely to cause cancer, increasing the concentration harmful substances don't stand around yourself. When LED lamps break, the scientist recommends removing the remains of the lamp using gloves and a mask, and disposing of it as hazardous waste, although at the moment, according to the law, LED lamps can be thrown away with regular household waste. The scientist also claims that manufacturers can easily reduce the amount of heavy metals, especially if government or federal services will somehow take care of limiting them.

However, LED lamps save energy and cause less pollution. environment than mercury-containing lamps, they are a more environmentally friendly alternative to CFL lamps. It is likely that in the future this type of lighting will become less harmful to vision and can be safely used in the same way as incandescent lamps. But for now, it’s better not to get too carried away with this type of lighting, and give preference to traditional lighting from incandescent lamps (of course, within reasonable limits, since incandescent lamps have low light output).

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