It discusses six aspects of lighting energy-saving measures

In this paper, saving as a starting point, through the lighting design light, lamp choices, the rational design of elaborate lighting and other aspects of the program, measures and analyzes the feasibility of energy-efficient lighting methods to provide more effective technical reference for the future of lighting design.

1 Introduction

Statistics show that China's building energy consumption is on the same latitude countries in the world three times, accounting for 27.8% of the country's total primary energy consumption; secondly, lighting, air conditioning and other electrical equipment, accounting for 46% of the total building energy consumption, China's building energy consumption is higher than in developed countries mainly in building insulation and refrigeration, heating systems in poor condition.

With the rapid development of real estate, the demand for ancillary lighting products is growing significantly. On power consumption, lighting products become after air conditioning, heating appliances second major energy consumer. Lighting energy consumption accounts for 25% to 35% of the total building energy consumption, accounting for 13% of the total electricity consumption. The process used in architectural lighting, in addition to its own light source power consumption than its lighting will produce the corresponding heat, which constitute part of the heat is one of the main energy source of the first large building "air conditioning, heating," the . Therefore, energy-saving lighting has become an important aspect of energy efficiency. At present great potential for energy-saving lighting, energy-saving programs in general can achieve energy savings of 20% to 35%, 20% of the conservative calculation, the national energy saving considerable value, imagine played a significant role in the national economy. In the relevant manuals for energy-saving lighting has been given precise definition, to promote energy-saving lighting, does not mean lowering the requirements for visual tasks and reduce lighting quality, energy-efficient lighting is to ensure lighting illumination standards and quality of the premise, to ensure that work is not reduced visual site requirements, aimed at reducing lighting system energy losses, the most efficient use of energy. Lighting specifications proposed in unit required illuminance and power consumption per unit area (W / m2.lx) reduced lighting energy consumption as indicators, and strive to improve illumination. Hereinafter, a plurality of energy-saving lighting technology solutions for analysis.

2, the scientific design of energy-efficient lighting

(1) reasonable lighting line: Loss lighting circuits accounted for about 4% of the input energy, the main factors affecting the loss of lighting circuits and power supply conductors are cross-sectional area. Most of the lighting voltage is 220V, single-phase two-wire lighting system may be, and for two-phase three-wire, three-phase four-wire three ways. Three-phase four-wire power loss is much smaller than other power supply lines. Thus, the lighting system should be adopted in three-phase four-wire power supply.


(2) a suitable switching control mode and take full advantage of natural light: Natural light is free of light, full use of natural light, energy-efficient lighting is one of the important ways, so we must rational design light switches, such as taking control of a separate window lighting etc. measures. Full use of natural light, the correct choice of natural light, but also improve the working environment, people feel comfortable, conducive to health. Take advantage of the utilization of the light receiving surface of the reflective interior, but also can improve the light reflection factor such as a white wall up to 70% to 80%, power saving can also play a role.


Select (3) Lighting the way: in meeting the standards of the condition in order to save electricity, should be properly selected general lighting, local lighting and mixed lighting in three ways. Tall plants such as machine shop, only a general way lighting is difficult to achieve with a lot of light luminance value fine visual tasks required, if each lathe install a partial illumination source, we can achieve very little electricity high illuminance.


(4) different illuminance values: Option illuminance lighting design is an important issue. Low illumination, can damage eyesight staff, affect product quality and production efficiency. Unreasonably high illuminance is a waste of electricity. Select the illumination must be adapted to the visual work carried out. Lighting design lighting design standards promulgated by the state may be selected illuminance, light environment illuminance reasonable value and excellent lighting quality formation can improve work efficiency, improve the user's mood, but also improve the comfort of the space we live in.


3, the light source, lamps, electrical components selection


In the construction industry, both manufacturing lighting needs, atmosphere rendering the space effect, are inseparable from the lighting device. So on energy, the choice of lighting products based on has become very important.


(1) electric light sources commonly used are: ① thermally induced photoelectric sources (such as incandescent, halogen lamps, etc.); ② gas discharge photoelectric source (such as fluorescent lamps, mercury lamps, sodium lamps, metal halide lamps, etc.); ③ solid photoelectric light sources (such as LED and electroluminescent devices, etc.). In these three types of electric light, the luminous efficiency of various power sources are very different, thermally induced photoelectric sources such as incandescent, higher body temperature, the greater the energy it radiates. Use of thermal luminescence principle made electric light source producing simple and low cost, but the luminous efficiency is low, and the rest of the energy consumed in the form of heat places. The gas discharge light-emitting device, such as fluorescent lamps (Florescent), metal halide lamp (Halide), high-intensity discharge (HID) lamps and other gas discharge luminous efficiency of the device will be much higher than the thermal radiation light source, their luminous efficiency of ordinary incandescent several times, under normal circumstances, you can gradually discharge high luminous efficiency of electric light source alternative to gas heat radiation light source. Fluorescent energy saving than incandescent 70% for height of less than 5m workshop and other indoor lighting applications used in offices, dormitories and ceiling. Compact fluorescent light-emitting efficiency is higher than ordinary fluorescent 5%, thin tube fluorescent energy-saving 10% than ordinary fluorescent lamps, therefore, compact fluorescent lamps and fine today, "Green Lighting Project" program launched energy-efficient electric light.


(2) high-pressure mercury lamp, high pressure sodium and metal halide lamps are gas discharge lamp, when the voltage characteristics are the current increases lamp voltage is not increased but decreased, must have a series of positive voltage characteristics element to balance this negative characteristic of this nature element called restrictor or ballast. Ballast impedance with high stability and good voltammetry, high power factor, and low power consumption. So as to stabilize the lamp current, lamp life. Reduce the power loss of the ballast is an energy saving aspect can not be ignored. As good quality 250W sodium lamp ballast power consumption is only 20W ~ 25W, and the poor quality of the power loss of up to 40W.


(3) primary role is the assignment of lamps to a light flux in the desired direction, and to improve the utilization of light to avoid glare. Generally higher efficiency lamps are used materials and advanced technology production of high-reflectance, such as electro-chemical polishing of high-purity aluminum; good light transmission properties of the shield, such as a light-transmissive glass or plexiglass; then there are better sealing performance, energy waterproof and dustproof, minimize the loss of light. Luminaire efficiency refers to the utilization of its luminous flux. Any material of lamps for light radiation flux after reflection and transmission, its efficiency is always less than 1. Suppose the same power source, equipped with a high efficiency lighting, 70% to 80% of its luminous flux are utilized, the other with a lower efficiency lamps, luminous flux is only 40% to 50% utilized. In comparison, the low efficiency of the light source lamp which the power consumed by nearly 30 percent wasted, failed to play its role in this - the point is often overlooked. Therefore, try to choose when selecting lighting distribution curve is good, high efficiency lamps. At present, some lighting manufacturers have developed to produce the reflection rate can reach 95% of the lamps in the actual luminance value calculated with respect to the ordinary lamps, reducing a certain number, which saves cost, but also reduce the total lighting electricity consumption.




In addition, the use of lighting in the process will inevitably be contaminated, such as aluminum oxide reflector, the guard inside and outside dust fouling, etc., will inevitably result in the loss of light, such as unscheduled maintenance, and the same reason described above, the light source most of the power consumed would be lost. Therefore, the choice of lamps to choose achieve IP55 sealing performance over lamps, in order to reduce the maintenance workload.


4, energy-saving lighting management


Good maintenance can save electricity and protect eyesight, enhance the lighting power management is an important aspect of energy-saving lighting. Energy-saving lighting management mainly in the implementation of energy-saving publicity and education and the establishment of energy-saving lighting system based, so that people develop the habit of turning off lights; installed meter by households, the implementation of the meter fee; electricity installation of a dormitory hoppers, limiting electricity, which can effectively reduce the lighting power consumption. When the lamp contamination, the luminous flux may be reduced to 50% or less of normal luminous flux. When light bulbs, lamps, glass, walls dirty, the reflectance and transmittance will be greatly reduced. To ensure the glow of the lamp, the lamp should be cleaned periodically, lamps and wall according to lighting conditions. When the lamp to flash or appear to flicker, to be replaced, because the gas discharge power consumption at start-up, electricity is much greater than usual, which can effectively achieve energy.


5, urban energy-saving lighting

Urban energy-saving lighting is by no means reduce the lighting standards to achieve, should speak saving at all levels to ensure compliance with the appropriate road lighting standards premise. Thus, each road lighting design and construction, we should make full use of solar energy, so that the illuminated environment to achieve lighting standards. First, determine the level of road lighting, rational design according to main roads, secondary roads, residential quarters, such as different lighting situations, in order to maximize the use of solar energy. Usually make several options were analyzed and compared, select from both economical and energy-efficient solutions. In terms of road lighting, generally using a larger installation height and spacing and high-power light source, it is more economical than using a smaller installation height and spacing and small power lamps and energy saving.

6, summary


Energy-saving lighting is a comprehensive work, many aspects involved. Maintaining the proper level of lighting under the premise, to achieve energy is entirely feasible, the potential for energy-saving lighting is great, only through continuous exploration and practice, think big, start small, to find truly achieve energy-saving lighting effects ways to make lighting costs can be reduced, so that the limited electricity to play a greater benefit.

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UV LED applications and protection issues

UV wavelengths between visible light and X-rays. Wavelength range is 10 ~ 400nm. However, many believe 430nm wavelength optoelectronic manufacturers also belong to ultraviolet light. Although many do not the human eye can see ultraviolet light, a visible part of the spectrum which is still named after the violet, UV LED in the past few years has made considerable progress. It is not only the production of solid-state UV devices of technological progress results also benefited from increased demand for environmentally sound production of UV lamps.

UV LED photoelectric current supply on the market contain a wavelength range of 265 ~ 420nm, there are a variety of packages, such as perforation, surface mount and COB. UV LED generator has a variety of unique applications, however, each generator on the wavelength and output power are independent. Under normal circumstances, use the LED UV light can be divided into three areas. They are respectively defined as UV-A (UVA), UV-B (UVB) and U V-C (UVC) (see Figure 2).

Full application

UV A-type device 1990 has already begun production. The LED is generally used in such counterfeit detection or verification (currency, driver's license or file, etc.). These applications require very low power output, wavelength range actually used is in the range 390 ~ 420n m, the lower wavelength product is not suitable for the application. Because these LED on the market long life cycle and easy to manufacture, it can be used as a variety of UV light sources and the cheapest product.

UVA LED element areas in the past few years has been greatly increased. This wavelength range (about 350 ~ 390nm) is the most commercial and industrial applications in the production of materials such as adhesives, coatings, inks and UV curing. Due to efficiency, cost reduction and system miniaturization, LED lights than traditional curing techniques, such as mercury or fluorescent lamps, has a greater advantage. Therefore, the supply chain continues to promote the use of LED technology, making use of LED curing the trend becoming increasingly apparent. Although the cost of the product this wavelength range is significantly higher than the UV A region, but steady increase in manufacturing output and rapid technological progress is gradually reduced prices.

Lower UV A and UV B higher wavelength range (approximately 300-350nm) was recently commercialized fields. These devices have great potential to be adapted for a variety of applications, including UV curing, biological medicine, DNA analysis, and various types of sensing. This three ultraviolet spectral range there is a significant overlap. So, the choice, not only to consider what is best for the application, we also need to consider what is the most cost-effective solution. Because usually it means higher lower wavelengths of LED cost.

UV B and UV C wavelength range (about 250 ~ 300nm) is a field still in its infancy largely. However, the application of these products in a warm and needs air and water purification system is very strong. Only a few companies have the ability to produce UV LED in this wavelength range, and a smaller number of companies to produce enough life, reliability and performance characteristics of the product. Therefore, the cost UVC / B device is still high, difficult to use in some applications. However, the first commercial UVC LED disinfection system was launched in 2012, which helped push the market forward.

Good protection

A common question about UV LED is: they pose a security risk it? As described above, UV light has various levels. One of the most common source is an ultraviolet lamp black. The product has been used for decades for use in a poster produced luminescent or fluorescent effect, as well as paintings and currency validation. These light bulbs generally produced in the UV A spectral closest to the wavelength of visible light and have lower energy. Despite the high exposure has been linked to skin cancer and other potential problems, such as skin accelerated aging related, but this part of the UVA spectrum of UV light are the three most secure. Light-emitting diodes (relative to a standard incandescent or fluorescent bulbs) are also highly directional, and the viewing angle is very narrow. Look into the UV LED can damage the eyes. Therefore, the user is best to avoid exposure to UVA products.

UV C and most of the UV B light is mainly used for sterilization and disinfection. These wavelengths of light not only harmful microorganisms, if in contact with it, for humans and other life forms are equally dangerous. These LED lights should always be shielded, and never use the naked eye look, even if it is emitting very little. Exposure at these wavelengths of light, can cause skin cancer and temporary or permanent vision loss or impairment.

All UV devices should have warning labels. Also, before you buy UV C or UV B ultraviolet light, many manufacturers require every customer to sign a document stating that they understand and agree that use of these products and process matters.

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Plant Lighting Tips: plant growth five monochromatic

Light is essential for plant growth and development of the environmental factors. It is not only the basic energy of photosynthesis, plant growth and development and is an important regulator. Plant growth and development not only by the amount of light or light intensity (photon flux density, photonfluxdensity, PFD) constraints, but also by the quality of light that is, different wavelengths of light and radiation, and they affect different composition ratios.


Plant lighting knowledge: plant growth five monochromatic

The solar spectrum can be roughly divided into ultraviolet radiation (ultraviolet, UV <400nm, including UV-A320 ~ 400nm; UV-B280 ~ 320 nm; UV-C <280nm, 100 ~ 280nm), visible or photosynthetically active radiation (photosyntheticallyactiveradiation, PAR, 400 ~ 700nm, where the blue 400 ~ 500nm; green 500 ~ 600nm; red 600 ~ 700nm) and infrared radiation (700 ~ 800nm) of three parts. Since absorbent stratosphere (stratospheric) ozone, UV-C and UV-B can not reach most of the Earth's surface. Reach the ground because of the intensity of UV-B radiation, the time (the time of day, season) geography (altitude and latitude), weather (presence or absence of clouds, thickness, etc.) and other environmental factors such as air pollution and different changes .

Able to detect changes in plant growth environment in light quality, light intensity, subtle changes in the duration and direction of the light, start essential for survival in this environment physiology and morphology. Blue, red and far-red light to play a key role in the control of plant morphogenesis of light. Photofrin (phytochrome, Phy), hidden flower elements (cryptochrome, Cry) and to the light elements (to light protein, phototropin, Phot) these light receptors receive light signals and signal transduction initiated by changes in plant growth and development.

Here, the monochromatic light means light in a specific wavelength range. Different experiments with the same kind of monochromatic light wavelength range is not exactly the same, and often other monochromatic light have different degrees of overlapping bands, especially with a wavelength close especially before monochromatic LED light source appears. This will naturally have different and even conflicting results.

Red

Red (R) suppressed between elongation, promote lateral branching and tillering, delayed flower differentiation, increased anthocyanin, chlorophyll and carotenoids. Red light can cause positive Phototropism Arabidopsis roots. Red light has a positive effect on the plants to biotic and abiotic stress resistance.

Far-red (FR) in many cases can offset red light effect. Low R / FR ratios lead to reduced kidney bean photosynthetic capacity. In the growth chamber with white fluorescent lamp as the main source, with far-red LEDs supplementary radiation (emission peak 734nm) anthocyanins, carotenoids and chlorophyll content decreased, leaving the plant fresh weight, dry weight, stem length, leaf length and leaf width increases. Supplemented FR role in promoting the growth of light may be increased due to the increase of leaf area caused by absorption. Plant leaves under low R / FR ratio grown Arabidopsis R / FR grown big and thick, large quantities of biomass, strong ability to adapt to the cold. Different proportions of R / FR can also change the salt resistance of plants.


Blu-ray

In general, increasing the share of white light blue light can be shortened internodes, reduced leaf area, reducing the relative growth rate and increasing N / C (N / C) ratio.

Higher plant chlorophyll synthesis and chloroplast formation and having a high chlorophyll a / b ratio and the low levels of carotenoids in Sun chloroplasts requires blue light. Photosynthetic rate decreased umbrella algal cells under red light, blue light or to add some blue photosynthetic rate after rapid recovery in continuous red light. When dark tobacco grown cells were transferred into a continuous blue light 3d, the ribulose bisphosphate carboxylase / oxygenase (rubulose-1,5-bisphosphate

carboxylase / oxygenase, Rubisco) and total chlorophyll content increased dramatically. Consistent with this, the unit cell culture has increased dramatically within the dry weight of the liquid volume, whereas in a continuous red light is very slowly slight increase.

Obviously, for plant photosynthesis and growth, it has only red light is not enough. In a single red LEDs light wheat life cycle can be completed, but in order to obtain a large number of tall plants and seeds, must be added the right amount of blue light (Table 1). In a single red light grown lettuce, spinach and turnip plants production was lower than the growth of red and blue light combination, and a combination of red and blue light blue containing appropriate plants grown under comparable production plants cool white fluorescent grow. Similarly phase, single red light in Arabidopsis can produce seeds, but the plants grown under cool white fluorescent lamps compared with the reduction in the proportion of blue (from 10% to 1%), a combination of red and blue light Growth plants bolting, flowering and the results are delayed. However, in a combination of red and blue plant seed yield of 10% blue light cool white fluorescent grow only half the growth of plants. Blu-ray excess inhibit plant growth, internode shorter, branching decrease, smaller leaf area and total dry weight decreased. There are obvious differences in plant species of blue needs.

It should be noted that while some showed different plant morphology and growth difference spectrum blue proportion with the study of different types of light sources made about, but due to the composition of the different types of light-emitting non-blue light is different, the conclusion is still problematic. For example, while soybeans and sorghum plants were grown under the same light intensity fluorescent dry weight and net photosynthetic rate per unit leaf area meter was significantly higher than the growth of plants under low pressure sodium lamps, but these results can not be entirely attributed to the low pressure sodium lamp blue lack, I am afraid and under low pressure sodium yellow, green and orange light too much about too little.

Green

White light (including red, blue and green) tomato seedlings grown under dry weight was significantly lower than the red, blue light grown seedlings. Spectral test results in tissue culture growth inhibition suggests that the most harmful light quality is green with a peak at 550nm. In the green light to get rid of the growth of marigold height, fresh and dry weight increase of 30% to 50% higher than plants grown under full-spectrum light. Full-spectrum light up green cause plant is short and dry, fresh weight reduction. Removing the green light to strengthen marigold flowers, and additional pink and green lettuce inhibit flowering.

However, there are studies to promote green growth. Kim et al (2006) concluded that a combination of red and blue light (LEDs) Supplementary results Green concluded: inhibition of plant growth when the green light more than 50%, and in less than 24%, the ratio of green to strengthen plant growth. Although the combination of red and blue on additional green LED light in the background provided by the green fluorescent lead lettuce shoot dry weight increased, but additional strengthening of green growth, lower than the cold white light produced more biomass conclusion is problematic: (1) they observed biomass dry weight is only aboveground dry weight, if included underground root dry weight, the result may be different; (2) red, blue and green tricolor lamp grown lettuce shoots major plant dry under cool white fluorescent growth is likely to be contained in the three-color light green (24%) is far less than cool white fluorescent lamps (51%) of the results of that cool-white fluorescent green tricolor inhibition greater than results lights; (3) a combination of red and blue light grown plants photosynthetic rate was significantly higher than the result of the growth of green plants under the previous support speculation.

Effects are usually green and red, as opposed to the blue effect. Green can be reversed blue-promoted stomatal opening. However, treatment of seeds with a green laser is able to make long radish and carrots to control 2 times larger. A dim green light pulse can accelerate the dark grown seedlings elongation, namely, to promote stem elongation. With a single green light from the LED light source (525nm ± 16 nm) pulses (11.1 μmol · m-2 · s-1,9s) treated Arabidopsis albino, resulting in increased stem growth and reduce the rate of plastid transcript.

Plant lighting knowledge: plant growth five monochromatic light (2007) based on the past 50 years Plant photobiology studies, discussed green plant growth, flowering, stomatal opening, stem growth, chloroplast gene expression and plant growth condition role in regulating on that green and red sensing system, Blu-ray sensors regulate plant growth and development in harmony. Note that, in this review, green (500 ~ 600nm) is extended to include the yellow part of the spectrum (580 ~ 600nm).

Yellow

Yellow (580 ~ 600nm) to inhibit the growth of lettuce. Respectively, with different proportions of red chlorophyll content and dry weight, far-red, blue, yellow and UV mapping results show that only yellow light (580 ~ 600nm) can be explained by differences in high pressure sodium lamps and metal halide lamp two growth effects, That inhibits the growth of yellow. And, yellow (peak 595nm) on cucumber growth inhibition is stronger than green light (peak at 520nm).

Something about yellow / green effect conflicting conclusions, those studies may be due to the wavelength range of light used inconsistent. Further, since some researchers put 500 ~ 600nm light are categorized as green, yellow so on (580 ~ 600nm) on plant growth and development of literature rarely.

Ultraviolet radiation

UV radiation to reduce plant leaf area, inhibition of hypocotyl elongation, reduced photosynthesis and productivity, the plant susceptible to attack by pathogens, but can induce the synthesis of flavonoids and defense mechanisms. UV-B can reduce the amount of ascorbic acid and β- carotene, but can be effective in promoting anthocyanin synthesis. UV-B radiation-induced dwarf plant phenotype, small and thick leaves, short petioles, increase axillary branching and root / shoot ratio of change.


Growth in greenhouse study results from 16 rice cultivars China, India, the Philippines, Nepal, Thailand, Vietnam and Sri Lanka seven different regions show that additional UV-B results in an increase of the total number of raw materials have four cultivar (which reached a significant level of only one, from Sri Lanka), less 12 cultivars (which reached a significant level 6); those of UV-B-sensitive leaf area and tiller number cultivars are significantly reduced ; chlorophyll content increased with six cultivars (which reached a significant level 2); photosynthetic rate was significantly lower in the five cultivated species, and significantly improve has a cultivated species (its total raw number of substance significantly increase).

The proportion of UV-B / PAR is an important determinant of plant response to UV-B. For example, UV-B and PAR combined effect of shape and mint oil production, high-quality oil production requires a high level of natural light unfiltered.

It should be noted, laboratory studies the impact of UV-B, although the identification of transcription factors and other molecules, physiological factors play a role, but due to the use of higher levels of UV-B, UV-A does not accompanied and often very low background PAR, the results often can not be mechanically extrapolated to natural environments. Field studies often use UV light to improve or reduce UV-B filter level.

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Eye eye can really do? Tips to buy LED lights small tricks

Whether parents give the child's desk, or face the computer crowd, a light external factors are very important in order to protect eye health, Eye of the purchase is also very important, what kind of lighting conditions best suited eye, how about between LED lights and eye of the difference and the link?

Lighting purchase Mistakes

Light is too strong

Reading in dim conditions poor, in reading the same place too bright eyes will cause harm, under the lights too bright conditions is a direct result of the reflection enhancing, reducing the resolving power of the eye, resulting in visual fatigue, which is a short-sighted The main predisposing factors.

Choose white light

White light is also known as the cool light, the color temperature of the lamp in accordance with the general terms about 6000k, since white light provides maximum brightness contrast, the weakest intelligent cause visual reaction, it will be more likely to induce eye fatigue.

The higher the frequency, the better

Lights flicker frequency is selected from a number of entry-level light concerns certain people, in general, the higher the frequency of flashing lights, the relative degree of visual fatigue will be reduced, but also one of the factors stroboscopic visual fatigue, but also can not completely rely on Strobe to determine lighting quality.

　　              Start with: How to choose the right Eye

Eye mainly through light sources, light color and intensity of the three aspects to start, choose the most suitable product for their own viewing conditions.

Source Type:

Eye of the type of light source is divided into point, line, surface three point light source is a light bulb, a line light source as a lamp, and a larger overall surface light source is a light emitting body, three surface light source to the best line light Secondly, the lowest point light comfort effect.

Color temperature and light color

5000k color temperature warm in the light of the following as the most suitable for close reading and writing of lighting, table lamp light with a pale yellow color is the best, it can effectively reduce the intensity of the light reflected by the white paper, while improving the resolution of the eye.

Light intensity

Eye light intensity also choose the most important factor in the choice we will find next to the lamp lumens of an option, from the data, the strongest illuminance resolution at about 200 ~ 300lx intensity light to read and write but also make the eyes feel the most comfortable.

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How to solve the LED power supply design of EMC / EMI problems

Electromagnetic compatibility (EMC) is the study of accident electromagnetic energy in electricity generation, propagation and reception, as well as the harmful effects caused by this energy. EMC's goal is in the same environment, electromagnetic phenomena involving different devices are able to operate normally, but this is not the environment to any device the ability to produce intolerable electromagnetic interference. Traditionally said, EMC contain EMI (electromagnetic interference) and EMS (electromagnetic susceptibility) in two ways.

Electromagnetic interference (EMI) is any conduction or electromagnetic field associated with the applied voltage and current generated will reduce the performance of a device, equipment or system, or adversely affect the electromagnetic phenomena.

LED power of electromagnetic interference, the main aspects of engineers to consider are: circuit measures, EMI filtering, component selection, interference shielding and printed circuit board design.

LED power supply design for engineers, electromagnetic interference is a key issue has been present in the design. How can I solve this problem? Let's look at several factors that influence the electromagnetic compatibility.

A number of factors affect the EMC


Circuit configuration (1) of the drive power source


Initially the LED power supply is linear, but linear power at work will be a lot of energy loss in the form of heat. Linear power work, so he must have changed from high to low pressure pressure device, generally are transformer and then rectified output DC voltage. Though bulky, heat, the advantage of external interference, small electromagnetic interference, but also easy to solve.

And now more and more use of LED switching power supply, are in the form of PWM LED driver power supply is to work in the power transistor is turned on and off states. In conduction, low voltage, large current; shutdown, high voltage, current, and therefore the loss of power semiconductor devices produced is small. The disadvantage is obvious, electromagnetic interference (EMI) and more serious.


(2) switching frequency


LED power electromagnetic compatibility problem is generally the power switch circuit. The switch circuit is one of the main sources of interference switching power supply.

LED drive power switching circuit is the core of the switching circuit consists of switches and high-frequency transformer. it produces du / dt has a relatively large pulse, wide-band and rich harmonics.

The main reason is the high-frequency pulse interference: load switch high-frequency transformer primary coil is inductive load.

Figure 1: Switching spikes generated

Turned the moment, the primary coil produces a large inrush current, and the emergence of high surge peak voltage across the primary winding; opened and the moment due to the leakage flux of the primary coil, resulting in no part of the energy transfer from the primary coil to two secondary coil, with a damped oscillation circuit formed spikes superimposed on the turn-off voltage, forming a turn-off voltage spike.


Produce more high-frequency pulse emission, the periodic signal to produce more emissions. In the LED power supply system, the switching circuit generates current spikes, and when the load current changes will generate a current spike. This is one of the sources of electromagnetic interference.


(3) Ground

In all EMC title, the main problem is caused by improper grounding. There are three signal ground methods: single-point, multi-point and mixing. When the switch circuit frequencies below 1MHz, use a single-point ground method, but not suitable for high frequency; in high frequency applications, preferably multi-point grounding. The ground is mixed with a low-single-point ground and the high frequency multi-point grounding method. Ground layout is the key, high-frequency digital circuits and grounding circuit low-level analog circuits do not mix.

(4) PCB design

Appropriate printed circuit board (PCB) routing is essential to prevent EMI.


Reset circuit design (5) Smart LED power supply

In the LED power supply, LED power supply with a lot of intelligent MCU control, and some control of single LED power switching circuit duty cycle, SCM watchdog system running the entire LED power plays a particularly important role, since All sources of interference can not be all it would be a valid defense barrier which provides error correction or addition to, once entered the CPU interfere with the normal operation of the program, then reset the system combines software action. Commonly used to reset the system has the following two:


① external reset system. External "watchdog" circuit can also be used to design their own special "watchdog" to build chips. Thus, if the system program stuck in an endless loop, and the loop has happened to "feed the dog" signal, then the reset circuit can not achieve its proper function of.

② Now more and more LED power supplies have reset the system on its own slice, so users can easily use its internal reset timer, but some intelligent LED power supply control circuit reset command is too simple, so there will still be an infinite loop as described above as "feed the dog" instruction to lose monitoring role.

Hardware Processing Method II of interference measures

To solve the problem of electromagnetic interference LED drive power is available from the following aspects:

1. reduce the switching noise on the power itself

① soft-switching technology: increase the inductance and capacitance element in the original hard switching circuit, the resonant inductor and capacitor to reduce switching process of du / dt and di / dt, so that drops the voltage switching device opened before the current up, down prior to the current rise in voltage, voltage and current to eliminate the overlap time or off.

② switching frequency modulation technique: by modulating the switching frequency fc, the focus fc and its harmonics 2fc, energy 3fc ... spread on the band around them, in order to reduce EMI amplitude of each frequency point.

Select ③ Component: Choose easy to produce noise, easy conducted and radiated noise components. Typically particular note is that the choice of diodes and transformer windings class components. Reverse recovery current, shorter recovery time fast recovery diode is ideally suited for high-frequency switching power supply rectification section.

④ rational use of EMI filters: One of the main purposes of the EMI filter, a power grid noise is electromagnetic interference, radio frequency interference it belongs (RFI), which conducted noise spectrum is substantially 10KHz ~ 30MHz, up to 150MHz.

In general, differential mode interference amplitude, low frequency interference caused by the smaller; common mode interference amplitude, high frequency, can also produce radiation through the wire, the larger the interference caused. To weaken conducted interference, the most effective way is to install the EMI filter input and output switching power supply circuit.

LED power generally use a simple single-stage EMI filters, including common mode choke and filter capacitor.

Figure 2 is a conventional LED power filter, L, C1 and C2 are used to filter out common mode interference, C3 and C4 series mode interference filtered out. When the common-mode interference occurs due to the same magnetic flux direction in the two coils L, after coupling the total inductance increases rapidly, so the common mode signal exhibits a large inductive reactance, so that is not easy to pass, so called common mode choke coil. Its two coils are wound on a ferrite toroid low loss, high magnetic permeability. R is the discharge resistance can be accumulated charge on C3 vent let go, to avoid charge accumulation affect the filter characteristic, but also to power after the end of the power line L, N is not charged, to ensure the safety of use.

Figure 2 conventional LED power filter

⑤ EMI filter can effectively suppress electromagnetic interference Switching power adapter

FIG. 3 is a curve without EMI filter switch on the power adapter 0.15MHz ~ 30MHz conduction noise waveform.

Curve b is a waveform added after EMI filters, electromagnetic interference can be attenuated 50 db (Uv) ~ 70 db (uV). Clearly, better EMI filter insertion.

Front and rear transmission electromagnetic interference filter was added to the noise voltage across the load, respectively U1 and U2, the formula is 20lgU1 / U2.

Expressed in decibels dB insertion loss, the greater the decibel value, indicating a stronger ability to suppress noise.

Add loss measuring circuit shown in FIG. e is the noise signal generator, Zi is the internal impedance of the signal source, ZL is the load impedance, and generally 50 ohms. Optional noise frequency range 10KHz ~ 30MHz. First were measured at different frequencies of noise around U1 join EMI filter pressure drop across the load, U2, and then into the formula 20lgU1 / U2 calculated insertion loss values for each frequency, and finally export insertion loss curves.

Figure 3: adherence EMI filter before and after

2. cut off the route of transmission of the interfering signal

① power line disturbances can use the filter to remove the power cord. A reasonable and effective switching power supply EMI filter should supply line differential mode and common mode interference has a strong inhibitory effect.

② improve the electromagnetic compatibility design of PCB

PCB is LED power supply system support components and devices, which provide electrical components and connections between devices. With the rapid development of electronic technology, PCB density is increasing. PCB design quality great influence on electromagnetic compatibility LED power supply.

Practice has proved that, even if the circuit schematic design right, printed circuit board design properly, will adversely affect the reliability of the LED power supply.

PCB anti-jamming design includes PCB layout, wiring and grounding, which aims to reduce crosstalk and electromagnetic radiation PCB on the PCB circuit.

Also, the general transformer electromagnetic interference caused by the hum frequency is generally about 50HZ, improper wiring and grounding hum due to the multiplier effect of the frequency of the rectifier circuit is about 100HZ, carefully distinguish still perceptible.

The correct wiring method is to select the main filter capacitor pin as a centralized ground, strong and weak signal ground strictly separated, are summarized in the total ground.


Therefore, in the design of printed circuit boards, we should pay attention to the correct way to comply with the general principles of PCB design, and shall conform to the requirements of anti-jamming design.

3. The enhanced anti-jamming capability disturbed body

In the LED power supply system input / output is also the source of interference conductive lines, and receiving radio frequency interference signal source Pick up, we generally take effective measures designed to:

① adopt the necessary common-mode / differential mode suppression circuit, but also to take certain filtering and anti-electromagnetic interference shielding measures to reduce feed intake.

② take as much as possible under various conditions permit isolation measures (such as magnetic or optical isolation isolation), thereby blocking the spread of interference.

③ lightning protection measures

LED power system for outdoor use or exclusion from the introduction of indoor outdoor power lines, signal lines, to consider the system of lightning problems. Commonly used anti-lightning devices include: gas discharge tube, TVS (Transient Voltage Suppression) and the like. Gas discharge tube when the power supply voltage is greater than a certain value, typically tens or hundreds of V V, gas breakdown discharge, the strong impulse power line lead into the earth. TVS can be seen as two parallel and opposite direction Zener diode when the voltage across the conduction above a certain value. Which can be characterized by a transient current is hundreds of thousands of A's.

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LED power electronic load test errors and explain solutions

Want to improve test efficiency LED power supply, the most efficient and easy way is to choose the right electronic load. If knowledge is not familiar with the electronic load, or insufficient proficiency can not grasp it, and even cause a decline in confidence in the test results, which affects the quality of the product, but also lead to serious accidents. This article focuses on the principle of electronic load CV, and some errors LED power tests are introduced.

CV mode electronic load with load, is the basis for LED power supply tests. CV, is a constant voltage, the load current only tensile load device itself can not provide a constant voltage, the so-called CV, only by a voltage negative feedback circuit to output changes of the servo power supply LED current, the LED output capacitor charge balance, thus achieving a constant voltage. Therefore, the decision CV accuracy has two core elements:

Load Bandwidth
LED power output capacitor size

When high power LED output current ripple frequency, if the load insufficient bandwidth, you can not change current servo, caused concussion, concussion occurs when the load input voltage rapid change, LED output capacitance will be frequent high-current charge and discharge the detected current ripple at this time, will be much larger than the actual current ripple LED power supply during steady state operation.

When bandwidth is insufficient load, if the LED power supply output capacitance is large enough, volatility can be controlled within an acceptable range, but unfortunately, the power LED price competition is fierce, generally inadequate output capacitance, therefore, LED power supply for testing, load the bandwidth requirements are very demanding.

Bandwidth load indicators, manufacturers are not directly labeled only with reference to another indicator: full-scale current rise time, it is clear that the full-scale current rise time is smaller, the higher the bandwidth load. The higher the bandwidth load, the lower the power output of the LED capacitance requirements, in general, 10uS full-scale load current rise time, to meet the power needs of most LED test, but in theory, any load in CV mode next, there is the possibility of shock, in this case, when the LED output capacitor constant, the higher the bandwidth load, the smaller the volatility, the higher the confidence level test results, so users in the use of electronic load when testing, you must pay close attention to changes in load input voltage ripple Vpp, once it is out of range, the entire test results will no longer be credible, this point is very important, we must remember.

In CV mode, constant voltage, and current ripple are usually very large, and the load in order to improve test efficiency, data refresh rate is often high, so beating big data, many users in order to determine whether the load is suitable for LED test, in fact, this is a very serious misunderstanding, stable data or not, is actually very easy, you only need to increase the measurement time data filtering can be achieved, a short low-end electronic load, because of the low accuracy, so had large time scale filter, but instead a blessing in disguise, so that the data appears to be more stable, in fact, this is an illusion. To achieve accurate measurements, the fundamental approach is to increase the sampling rate can not increase the sampling rate, the measurement result is such confidence is very low, it may lead to serious quality accident.

Based on the above analysis, LED power supply testing, loaded with stringent requirements, mainly in the following points:

Full-scale current rise time is to ensure accurate load fundamental value as low as possible;

Data sampling rate, is the fundamental guarantee accurate measurement, the higher the value, the better;

Vpp real-time display of measurement data is to determine whether credible fundamental;

Filtering speed adjustment function, was able to get a small steady current data means;

Finally, drew attention to the market there are some load, known as LED power supply test dedicated electronic load, in fact, is a face-lift from General Electric load, but generally do not meet the bandwidth and sampling rate electronic load test requirements modified from its and did not improve their bandwidth because the bandwidth load technology is the core technology, and the cost is also closely related, it is difficult to improve, they tend to be improved through three ways in which the current data more stable, but also more credible.

The easiest way to increase filter strength, forcing the data is stable. So that this method is simple, easily lead to miscarriage of justice, causing mass accident.

Adjust the voltage feedback loop, voltage feedback signal strong filtering to reduce the current volatility. This method is just the opposite, to further reduce the bandwidth load, the situation is not very sharp shocks with shock, it has become smaller amplitude of oscillation.

Increase in internal load capacitance, this method can be suppressed flapping or amplitude, but the measurement of current ripple, ripple serious than the actual small, but helpful for testing the DC operating point. But the load rated voltage is generally higher, so the price and size of the high voltage capacitor is a very serious problem, and therefore it is difficult to ideal conditions, and often integrated with the first two methods. Another problem is that, in this situation, they tend to use a relatively inexpensive high-voltage capacitor solutions, it will bring a lot of parasitic problems.

This article introduces the principle of a comprehensive electronic load, especially in LED electronic load measurement errors exist in the process were highlighted. Moreover, in this paper, which also made a number of possible solutions, in order to obtain a more stable current data. I hope you can gain something after reading this article after.

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LED lamp power supply design should pay attention to what elements?

Currently, LED fluorescent lighting market more active, LED driver power supply manufacturers are mainly divided into three major types: The first is to make the development of LED chip or LED lamp factory, homeopathic downstream penetration; the second category is the original do is to do general lighting factory ; the third category is entirely newly opened factory, they have done before the power supply or other product or new business.

LED power

LED power LED lamp is a very important part, if the improper selection, LED lamp not play his rightful property, it may even not use normal lighting. Here LED fluorescent lighting power to do some small suggestion for your reference reference.

1.LED fluorescent constant current power supply Why must it?
Characteristics of LED semiconductor determines its influenced by the environment, such as temperature, LED current will increase; the increase of voltage, LED current will increase. Long-term than the rated current work, will greatly shorten the life of the LED. The LED is at constant temperature and voltage changes and other environmental factors, to ensure that the operating current constant.

2.LED fluorescent power to how we can match the light board?

Some clients to design the light board, find the power, find it difficult to have a suitable power supply, or too much current, the voltage is too small (as I> 350mA, V <40V); or the current is too small, the voltage is too high (eg I < 40mA, V> 180V), the result is a serious fever, low efficiency, or the input voltage range is not enough.

In fact, choose a string and then the best way, applied voltage and current on each LED is the same, but the effect of power able to play the best performance. The best way is to communicate and power supply manufacturers, tailored.

3.LED fluorescent power operating current is how much is the most appropriate?

General LED rated current 20 mA, some plants used to make the design 20 mA, in fact, this current work is very serious fever, after numerous comparison test designed to compare 17 to 19 mA is ideal design for the recommended 18 mA.

4.LED fluorescent power operating voltage is how much?

General LED recommended operating voltage is 3.0-3.5V, tested, most of the work at 3.125V, 3.125V so calculated according to the formula more reasonable. M light bead in series the total voltage = 3.125 * M.

5.LED lamp series-parallel plate with wide voltage to how wide it?

For LED lamp in a relatively wide range of input voltage range (full voltage) AC85 ~ 265V, the panel LED lamp series-parallel manner is very important. As the current supply is generally non-isolated step-down power, wide voltage, the output voltage should not exceed 72V, the input voltage range of 85 ~ 265V can be reached. That is, the serial number no more than 23 strings.

Parallel Number not too much, otherwise the operating current too serious fever, and recommended as 6/8 and / 12 and. Total current not exceeding 240 mA as well. There is also a wide voltage solution is to first use the L6561 / 7527 of the voltage raised to 400V, then the buck, the equivalent of two switching power supply, cost twice as expensive, this program cost is not high, there is no market.

6.LED series-parallel relationship with the PFC power factor and wide voltage is what?

PFC power supply currently on the market, there are three cases: one is dedicated circuit without PFC, PFC which is generally about 0.65; one is with a passive PFC circuit, light board horses prepared well, PFC generally about 0.92; also It is active with an active circuit 7527/6561 do, PFC can reach 0.99, but the cost of this program is more expensive than the second option doubled.

The second scenario is more so. For passive PFC circuit: also called valley-fill PFC circuit, its operating voltage range of the AC input voltage is half the peak. If the input is 180V, the peak is 180 * 1.414 = 254V, half the peak voltage is 127V, the buck minus differential pressure 30V, maximum output is 90V, so the maximum number of series 28 LED lamp beads string.

Therefore, in order to give relatively high power factor, number of series lamp beads can not be too much, otherwise, would not reach the low voltage requirements.

7.LED fluorescent constant current power supply precision how much would be the most appropriate?


Some current precision on the market power of the poor, like the popular market PT4107 / HV9910 / BP2808 / SMD802 programs constant program error of ± 8% or ± 10%, constant error is too large. General requirements ± 3% on it.

3% error, 6-way parallel, each of the error is about ± 0.5%, if it is 12 channels in parallel, each of the error is about ± 0.25%, the accuracy is sufficient. Accuracy is too high, the cost will be greatly increased. And in terms of LED, 17 mA and 17.5 mA little effect.

8. isolation / non-isolated

Usually made of isolated power such as 15W, LED lamp placed in its transformer bulky, difficult to put in here. Especially for T6 / T8 lamp, almost impossible, generally only do so isolated 15W, 15W more than the few and expensive. Therefore, the cost is not high isolation, the general non-isolated more mainstream, the volume can be made smaller, the minimum can be done 8 mm high, in fact, non-isolated safety measures well, the problem does not exist.

9.LED fluorescent power efficiency

Output power (output voltage * LED output current / input power). This parameter is particularly important, if inefficient means that a large part of the input power is converted into heat that comes out; if it is contained within the tube will produce a very high temperature, combined with our LED light efficiency than the one dissipate heat, will produce higher temperature superposition.

Our internal power supply Electronic parts life will be shortened with increasing temperature. So efficiency is to determine the battery life of the most fundamental factor, efficiency can not be too low, otherwise the power consumed in the heat too. Generally above 80% can, however, about the efficiency of the lamp plate matching connection.

10.LED fluorescent lamp power supply Dimensions

Height is a major limiting factor, generally used for tube T6 / T8 size requirements ≤9 mm height can not be too high. T10 tube height ≤15 mm. Length can be rather long, but easy to heat.

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You do not know the harm of low-quality LED lights

Chinese market is so new just came out, as long as the good sales, high customer focus, may be overnight, major markets throughout the country. Many manufacturers sinister, low material, same product can make different versions of specifications, say lamp beads, power, aluminum shell thickness and material (industrial scrap).

Take 3 * 1W high power Ceiling detail explanation:


Lamp beads: 3 * 1W meant to say, is composed of three 1W lamp beads, plus power, real power over 3W.

Now there are three common market 0.5W combination, a combination of three 0.75W, three 1W combination.


Power: Power is the key to see the current, whether constant current, belt wear protective current driver IC.


3 * 0.5W current general 150MA - 170MA around

3 * 0.75W current general 180MA - 220MA around

3 * 1W current general 300MA - 350MA around


Aluminum housing: the key to a surface treatment, reflective more delicate appearance, the higher the aluminum content, the higher the content of the coarse impurities.

Aluminum thicker the higher the price, the common 1.5MM 2.0MM 2.5MM 3.0MM


Manufacturers are generally black heart with a combination of 3 * 0.5W of power with cheap, inferior race thick aluminum to a good red, LED applications is a hot industry, but also to support the government's new energy-saving and environmental protection industries, but why is the black heart of our China factory with defective to reap huge profits.

Alert LED glare harm to human body


In recent years, the development of LED lighting presents a bustling scene. Like other artificial light, LED light radiation can theoretically cause little harm to humans. Injury occurs mainly in people's eyes and skin, such as skin and eye photochemical harm, harm the eye near ultraviolet, blue photochemical retinal hazard, aphakic photochemical retinal hazard retinal thermal hazards of skin and heat hazards, and both among the more vulnerable eyes. In addition, LED glare can also cause harm. Glare is on the horizon due to the distribution of brightness or scope inappropriate, or in space or time of the existence of extreme brightness and contrast, as well as cause discomfort and reduce the visibility of objects visual conditions, glare lighting quality evaluation is one of the most important factors .


Following the radiation hazard has been listed as "air, water, noise" outside the fourth largest environmental security issues facing mankind World Health Organization. Optical radiation is an important part of the radiation, its ultraviolet radiation and blue light radiation on the human body, especially significant. In recent years, with the development of LED technology and market requirements, radiance LED chip greatly improved, more and more narrow beam, plus part of manufacturers and excessive application of UV LED chip, blue band, so that the LED light radiation hazards become a problem can not be ignored. LED light radiation hazards mainly reflected in the near-ultraviolet radiation damage of the eye, retinal photochemical damage and Blu-ray radiation of heat damage.


Reporters from the experts responsible for optoelectronic inspection officer that "light biosecurity" unqualified person may lamps shine injury, also may hurt people's eyes. Especially the excessive use of blue or ultraviolet light emitting LED lights, more prone to leakage of blue or UV light bodily injury problems. Currently the EU has mandated LED lamp light biological safety testing, the experts called the country also should pay attention to.


In theory, the use of the type of lamps, LED lamps on people's health (not just of the eyes) minimal damage, or even that did not hurt. Of course, the premise is a must use regular brand manufacturers qualified by domestic or foreign CCC certification UL, CE and other types of security, electrical certification of LED lights. If you use poor quality LED lights, it is better not.

Inferior LED lights blue light hazard

Safety light environment once again sparked concern: on the one hand of a sharp rise in incidence of juvenile myopia; on the other hand home lighting, work according to the outdoor lighting is that even adults are eye health hazard. Lighting is not the brighter the better? How light environment was conducive to eye health? Experts point out that parents, teachers and the light source manufacturer, has a responsibility to popularize scientific knowledge consumption light source should be used in favor of the health of students and lighting no radiation, no flicker of energy saving lamps.

Users in the purchase of LED indoor lights, not only the lamp power, because the LED lamps are not the brighter the better.


Phenomenon 1: LED lamp price level of refractory

Expert: Mo buy less than $ 20 5W bulb

It is reported that consumers in the market to buy LED lamps indoor lights, we often see a puzzling phenomenon: a well-known brand 4W LED bulb price of 40 yuan, and some unknown brand of 5W LED Bulb but only sell 20 yuan a. Both bulb, in the end of the election Which bulb do? Many consumers told reporters that they tend to choose a more bright LED bulb.


It is understood that because of the color temperature, the higher the luminous efficiency, LED interior lights look more bright. However, in actual use, low color temperature looks more comfortable, the corresponding cost would be high. Ethernet sunlight, for example, in the morning and evening sun, the color temperature between 3000K ~ 3500K, softer look, at noon, the sun rises to 4000K color temperature to 4500K, it has been more glaring. Incandescent and fluorescent color temperature of 6200K has reached bottom.

Reporters learned that regular domestic manufacturers will be marked on the packaging bulb color temperature, color temperature commonly used is 2700k, namely ordinary incandescent color temperature, which is characterized by a warm feeling of light, but bright enough, for the bedroom nightstand, wall, etc. local lighting; 3000k color temperature is closest to the natural light, is a warm light, the light is both warm and bright, the overall lighting design is suitable for home; 5000k is white above, is a cool light, can make people concentrate, suitable for office, study, and other places use.

Experts: At present, in the lighting market, general household Indoor LED lamp power between 3W ~ 7W, 5W bulb about market prices generally at 50 yuan, if less than $ 20, then the LED indoor lights quality is certainly a problem, not only can not protect eyesight, but also greatly shorten the life of the light source. In addition, consumers in the purchase of LED indoor lights, not only the lamp power, because LED lighting is not the brighter the better.

Phenomenon 2: inferior LED lights blue light hazard

Expert: Mo cheap, buy big brands

Then LED lights from incandescent to energy-saving lamps. In recent years, energy-saving lighting products for social attention than ever before. In this regard, some of the medical profession and the electric light source experts have pointed out, there are serious blue overflow lot LED lamps, over time people will suffer irreversible retinal damage.

LED lamps have a visual impairment it really Lighting Research Institute of Fudan University, deputy director of Shan-end associate professor, told reporters:? "The principle of white LED is a blue LED chip white light after excitation yellow phosphor conversion of blue light hazard refers to the formation of the light source. 400 to 500 nm and blue bands if the brightness is too high, it may cause retinal photochemical damage after a long look into the eyes light. blue hazard depends Blu-ray dose received by the human eye in the light of the accumulation. "


"If you purchased a qualifying fixtures and used properly, LED lights are not more dangerous than traditional lamps." Insiders pointed out that, at present, the domestic LED lighting manufacturers have been more than 3,000 light our national standard "lamps and lamp systems biological safety ", the blue light hazard calculation method and quantization to make clear that, noting that LED lighting products, compared with other sources and there is no difference, within the scope of the safety limit of radiation exposure requirements.

Experts: Optical Engineering, Zhejiang University, Professor Mou with the rise, said the international community in accordance with the intensity of the blue light has been developed biosafety standards related to the Blu-ray and Blu-ray may harm the set value. For example, there will be no harmful blue light source product called "zero-products"; hazard will have a smaller blue eyes can not look directly at the light source product for a long time referred to as "a class of products"; there will be a greater source called blue light hazard "second-class products." LED lighting is currently used as a class and a class of substantially zero, if it is obligatory II were marked "the eye can not stare." Therefore, in the purchase of LED lamps, not freeloaders, to choose a big brand products.




Phenomenon 3: Eye of varying quality


Expert: china Optional 3C signs to look for


Lamps adults and children to learn, an indispensable tool for work. To prevent myopia, a good choice for children Eye, a problem many parents consider. According to the reporter, currently on the market Eye dazzling array of products, many products are advertised themselves as "no flash", or high-tech LED lights, and the price is much higher than ordinary lamps. What do these lights can not protect the child's eyes?


Reporters visited the Guangzhou city Carrefour, Trust-Mart supermarket, several lamp area to see Chin lamp products, half for children "Eye." Prices of these products varies, the same lamp, table lamp with the word "eye" and other, relatively speaking, a few hundred dollars more expensive than ordinary table lamp. Some LED's "Eye", the price is much higher than more.


Reporter observed, put on the shelf lamp, lamp did not indicate "eye" feature, ranging in price from 80 yuan to 300 yuan; and marked "eye" feature lamps, the cheapest to $ 300, expensive even 900 yuan. Reporters also found that, in addition to the difference in the price, a lot of "Eye" products are not related to the "3C" certification mark.


Experts say: "Eye" is currently mostly marketing concept, whether there is "eye" effect is not OK, consumers in the purchase process, we should pay attention to see the security certificate with the description, choose the best after-sales service products, and Note that the product 3C certification mark.


Warm Tips

Children's room light design coup

The study found that long-term use "full bright" light is one of the factors leading to high incidence of myopia of our young people. If the lamp brightness is much higher than the general brightness of the indoor environment, people will feel dizzy. Visible brightness large light fixture does not mean good, too bright will damage the retina. How can we let our children live in a relatively safe light environment experts to look at the safety measures?:

1 different designs in different regions.

Children's room both games, learning, sleep and other functions, different functional areas, lighting requirements are different; the light intensity and area of ​​the playing field can be slightly larger. Light intensity learning zone may moderate some of the focus. Sleeping area to try to soft light, warm, which helps the child to feel safe, to help sleep.


2 avoid uneven illumination.

A too bright and too dark in other parts, it is not balanced design. Therefore, in addition to the main light source, you can set up some type of auxiliary light source (such as wall lamps, floor lamps, table lamps, etc.), the intensity of light through different spatial position, angle to reconcile the difference between indoor light, in order to ease the eyes of a child fatigue and discomfort.


3 up to the reflected light.

If you want to use the indirect reflected light as ambient light, pay attention to make up the reflected light shade as much as possible, not reflecting downward. Because the reflected light downward direct light may make the child's eyes, can damage the child's vision.

4 caution Spotlight

If lighting is not good, it will cause the child mental stress. If you want to use spotlights illuminated wall art (such as frame), to avoid the glare of highlights. So, playing light when fired from the side of art, the light from the side, the glare of the bright spots will not be reflected directly to the human eye.

5 Select adjustable lighting

The best choice can adjust the brightness, angle of lighting, the light dimmed some of the night, increase the child's sense of security, to help children fall asleep as soon as possible. After the kids go to sleep, be sure to turn off the lights. Because the children sleep in the light, vision is impaired, a much higher rate of myopia than children to sleep in the dark.


LED industry to solve the problem of light pollution in action


In the LED is recognized as the best source of future time, the industry has frequently broke the poor quality LED light pollution problems. As a new light source, LED lighting technology and applications in recent years have made rapid development. At the same time, LED light source on human health security has been more and more attention. LED lighting as a healthy carrier will be more widely applied to our lives, then the use of different occasions, how to determine the safety of LED? For health LED lighting, is there a quantitative standard? How healthy lighting results of research and development combined with the market really, and guide enterprises to develop more scientific safe and healthy LED lighting products? this ponder the problems caused by the industry

A low color temperature LED light is hurt your eyes?

Known to have a school bully buy LED lights burn the midnight oil on peace:

Because the bedroom after lights out will be at 11 o'clock, but in order to be able to continue their studies after lights out, so on Taobao bought a hard to force the lamp, but it is more like a little warmer colors, bought a low color temperature of warm light, I do not know whether a low color temperature LED lights hurt your eyes, and it supports two lamp brightness adjustment, the level of brightness will damage the eyes?

Here is the Taobao introduction and lamp structure:





He buy is 7 w version, parameters are: 7 w: 36 single measuring 50 lumens brightness.The following actual usage:





So, it seems secretly LED lights, it will cause damage to the eyes? The following are users answered:

KLJ Menzies:

In fact, led eye injury argument is exaggerated, and too little to the color temperature, low power, low brightness is of course to affect smaller but low color temperature resulting in low brightness can cause eye fatigue more easily is yes! That is, you make do with use, so when you talk about science and health conditions developed a lighting, and will definitely think of something, then you will at least consider another idea: the hair must buy led? In the light so much led human eye injury, as it used to, in fact belong to the impact of the unknown, do not direct the eye a big problem! May be able to endure, this is your choice. .
Aaron Fan:

Damage to the eyes can not just simply look at the color temperature, but also need to focus on flash, brightness, color, color and other factors, but in general, in terms of relative 6000k, 3000k will make people more comfortable.

Warm your hands:

From single led lights, in all other conditions the same parameters, high and low color temperature color temperature little damage to the eyes. Because led white phosphor excited by blue light emitted blue light on the human eye does hurt, warm blue light is much lower than the proportion of white light contained, so with respect to white light, warm light damage is much smaller. Of course, the impact on the eye led lamp is not limited to the color temperature, color temperature for more than just the difference here.





Dragon Pool:
In general, the brightness is too high or too low, poor color, blinking light at the hardware level is the main factor affecting vision, when the color temperature within reasonable limits (commonly called yellow white is between about 3000-6500) when the color temperature with basic does not matter. With eye habits affect on vision much larger than the light source.




An Menghao:
In general, white light high point, low point Tommy Wong, people will feel more comfortable. Do not look directly at the light source. A desktop illuminance, do not read and write uncomfortable. Another is to use a computer, preferably with a background light, so the eyes will not light differences. After playing with this phone lights the eyes of a bad reason. Research also shows that, 5200K, reading literacy clearer. Finally, do not buy too cheap products, the lack of regulation on the market today, regardless of good or bad. Lighting products have to buy big brands! !




Ouyang orange juice:
Led by led lamps and light source, power supply and lamp shell composition will increase if the adjustable resistors. led light source itself relative to other sources on the human body damage is minimal, because the section led advantages, too ........ And led lamps whether damage to the eyes, depending on the quality of driving power. 10w led lamps cost less in light of only 1% to 10%, the cost of power in more than 50%. Large price range power supply itself isolated, non-isolated, electrolytic capacitors, and the inside of the vitality of price and quality uneven. led cool, natural color, it is warm sub occasions, and therefore not comparable.

Eyes wide open look at when buying lamps: 4 Group failed lamps boarded the "quality Heibang"

Recently, the Provincial Quality Supervision Bureau in the province launched a provincial supervision lamps and lighting products, from a total of Hefei, Huangshan Luan, Wuhu, Tongling, Bozhou lamps and lighting products manufacturing enterprises to extract a group of 19 samples. Sampling results show that 19 sample group, 15 groups qualified, unqualified four groups.


The exposure of the four groups substandard products are: Anhui Shao Yuan Electronics Technology Co., Ltd. July 28, 2015 production specification model "YPZ200 / 28-LM / RR" of "Shao Yuan Electronics" brand electronic energy-saving lamps its signs, lamp power, the initial luminous efficiency / luminous flux, harmonic currents and many other indicators of failure; Huangshan dry Long Electric Co., Ltd. in July 2015 production specification model "YPZ220 / 15-HS 15W · RR" self ballasted fluorescent lamps, the initial luminous efficiency / luminous flux indicators of failure; Anhui Ryder optoelectronic technology Co., Ltd. May 16, 2014 production, specifications for the "LD-SL120" of 14000lm lights, its internal wiring is substandard; Anhui extension electric lighting Co., Ltd. November 30, 2014 production, specifications for the "TD-KJ-200" factory of LED lights, its structure, internal wiring is substandard.



For the inspection found problems related to product quality, the provincial quality supervision departments to remind consumers in the purchase of such products, to choose a reliable service to protect well-known producer of brand-name products. At the time of purchase, consumers need to check the product identification, pay attention to product specifications, models and trademarks should be consistent with the description, there should be national compulsory certification mark on the product specification or nameplate, manufacturer name, product factory inspection certificate, performance standards code and so on. In addition, consumers also needed to choose the right products, not simply the pursuit of low-cost, low price to avoid straying into the trap.

LED panel light components and technology Detailed

The development of LED lighting industry, as the ramifications of the LED backlight LED panel light, its light uniformity, no glare, delicate structure to give a lot of people's favorite, is the new trend of modern fashion indoor lighting.


      01:The main part of the LED panel light

           

1. The panel light aluminum frame:

Is the main channel LED cooling, Simple and elegant appearance, you can use ZY0907, die stamping using low mold costs, processing costs are low; die-cast aluminum frame IP rating may be a bit high, surface texture, and overall appearance, but the initial investment cost of mold higher.

2.LED source:

Typically LED lamp beads using 3528, it was 3014 and the use of low cost 5050.3014 and 5050, slightly worse luminous efficiency, the key is its light guide network design problems. 3528 light-efficient outlets common good.

3.LED light guide:

The sides of the LED light refracted through the network so that uniform light derived from the front, the light guide plate is the key point LED panel light quality control. Network design is not good, to see the overall effect on the poor light, usually appear in the middle on both sides of dark light, or light into the Department has occurred with light or dark areas visible locally, and then there are different angles or brightness inconsistent. To improve the efficiency of light guide plate depends mainly on the design of the network, followed by the quality of the plate, but did not need superstition famous line of the plate, the light transmittance between the plates is usually qualified almost the same. General small LED lights are a direct factory to buy the common use of the light guide plate, you do not need to re-proofing design, many manufacturers use the public version of the usual quality standards.

4.LED diffusion plate:

The homogeneous light guide plate export, but also play the role of fuzzy outlets. 2.0 General use acrylic diffusion plate or sheet material PC, PS handicap is lower cost materials, acrylic and high light transmittance higher than PC, acrylic weak brittle anti-aging properties, PC prices slightly expensive, but the anti-aging properties strong. Diffusion plate mounted on the network can not see the future, and the transmission rate to about 90%. Acrylic light transmittance 92%, PC is 88%, PS probably also 80%, we can choose the diffusion plate material according to the needs, for most manufacturers are using acrylic material.

5. Reflective paper:
Reflected off the back corner of the light guide plate in order to improve light efficiency, usually RW250.

6. Rear cover:

The main function is to seal LED panel light, usually with 1060 aluminum, can also play a little cooling effect.

7. The drive power:

There are two kinds of LED driver power supply, one constant current power supply, high efficiency of this mode, PF value up to 0.95, cost-effective; the second is to use a constant voltage with constant current power supply, stable performance, but low efficiency, high cost, generally use this is the main power outlet, the other requires a certification request shall use of safety power supply. In fact, home use constant current power supply is very safe, because users are difficult to reach power, and the use of light itself is safe low voltage.

8. Install the pendant:

Hanging wire, mounting brackets for mounting and other accessories.

From the point of view of quality control, to improve the light efficiency of the additional money in the LED light source and LED light guide plate is the most effective, from the market point of view, the additional money in the aluminum frame cover pendant, etc. you can enhance product quality.

          02:LED panel light of the three key technology

Light performance (light): Optical performance of the LED panel lights are mainly related to luminosity, spectral and color and other aspects of performance requirements. According to the latest industry standard "semiconductor light-emitting diode test method", the main emission peak wavelength, spectral radiation bandwidth axial luminous intensity angle, luminous flux, radiant flux, luminous efficiency, chromaticity coordinates, correlated color temperature, color purity and dominant wavelength, color rendering index and other parameters. LED panel lights commonly used white LED, color temperature, color rendering index and illuminance is particularly important, it is an important indicator of the atmosphere and lighting effects, and color purity and dominant wavelength is generally not required.

LED mainstream practice within the industry is later packaged LED chip light source or light source module is formed, when the re-lamp made in light distribution, which is used in the original practice of traditional light sources, because the traditional light source is a 360 ° light. If you want to use the light guide end, Philips is currently the best of traditional lamps do a light loss of 40%. The lamp optical parameters of our many domestic manufacturers of LED downstream applications are in fact optical parameters of the chip or the light source, instead of the optical parameters of the overall lighting of the indicators.

How to better improve the performance of light, it is the world's latest technology in the chip package to do with light, a light guide out of the chip, to maintain maximum light output, so that light loss rate of only 5% -10%. As technology continues to improve, more and more light loss rate will be low, the light source efficiency will be higher. Also with such light fixtures do not need light, relative lamp efficiency will be greatly improved, making it more widely used to functional lighting, forming a considerable scale market channels. Therefore, a good LED supplier, we are a top priority, we do not need to spend a high price to research how to go with our LED light as well, do not need to spend a lot of time and experience allows engineers to use simulation software, the easiest way is to let the white LED suppliers to match. You know, as our engineers to use simulation software, then action is required input and output. Import data input and output the results of the simulation that is preliminary, it requires preliminary data must be accurate in order to correct the rear end of the simulation.

Thermal properties (structure): the lighting of the LED luminous efficiency and power to provide one of the key LED industry, in the meantime, LED PN junction temperature and shell heat issues is particularly important. PN junction temperature of the lamp body temperature the greater the difference, the greater the resistance, along with the light energy is converted into heat energy consumed in vain, and in severe damage to the LED. A good structural engineer, not only to consider the structure of the lamp and LED thermal resistance, but also consider the shape of the lamp is reasonable, fashion, new, of course, reliability and maintainability, and usability, it is necessary to stand designer perspective to think about, but also from the user's point of view to consider products.

Today common technique is the use of aluminum plate package, and chip cooling light conversion efficiency aluminum plate package are present core technology bottleneck, can not effectively control the junction temperature stably maintain a high power light output, and the application will be higher because the chip light efficiency required greater area of ​​the aluminum plate, it will increase the cost and volume of applications, very inconvenient. So how to get out of this misunderstanding new paths is a central feature of the new technology. In keeping costs low and passive cooling of the premise, the use of high heat transfer medium, through new devices / Lamps overall structure, reduce the thermal resistance, junction temperature reduces the PN junction, PN junction work within the allowable operating temperature, keeping the maximum amount of photons output, the minimum requirements are as follows:


(1) Ultra-low thermal resistance material, the overall structure of rapid cooling techniques;

(2) high thermal conductivity, anti-UV packaging technology;

(3) Application of low environmental stress structure technology;

(4) the overall thermal resistance of <20K / W, junction temperature <80 degrees;

(5) LED illumination module temperature controlled at below 65 ℃.

Electrical properties (electronic): If a lighting likened a girl, then with just her meaning, structure is her looks, her heart is electronic. (Always catches the eye of those who look beautiful, stylish beauty who is also true product). People no heart no life, no electronic lighting power is not a good drive power also determine the life of a product. Criteria and parameters electronics often much more complex than the structure, the early R & D effort into relatively large. Current technology trend is changing and updating, one day a kind, the engineers have to spend a lot of effort to learn, absorb and break down, application of new technologies. Electronic pre-plan design, implement medium-term, post-forming process for an entire documented form data which is the design of the most complicated things. For example: a pre-program a power supply design, product profiles, standards based, in accordance with safety standards, electrical performance expectations, process requirements, materials evaluation, testing methods, and so have formed the system files.

LED drive power in the field, and now as an industry leader MOSO company's development path, full of legendary. For the LED industry keen sense of smell, MOSO head Gu Yongde led his team in 2006 began R & D power LED. Today, MOSO world's leading technology has been leading the LED lights intelligent drive the trend, offered to provide the most reliable drive solutions for intelligent LED street light manufacturers, which in turn is a leading concept model.

              03:Powerful LED drive power role

LED power supply as the core components of LED lights, like LED heart, LED drive power directly determines the quality of LED lamps.

First, the structural design, outdoor LED drive power must have strict waterproof function, otherwise, can not afford outside harsh environment.

Secondly, LED drive power lightning protection is also crucial. The outside world will inevitably encounter when working thunderstorms, lightning protection function if no drive power, will directly affect the LED lamp life, increase lamp maintenance costs.

Finally, on the selection of raw materials, its reliability must meet the needs of its life, the functional properties required good enough.

Currently LED chip theory of life is about 100,000 hours, life-limited parts and components industry To match, select key components must be perfect DMT, DVT verification management to ensure long life and reliability requirements, or life is not enough power, lamp life will not be achieved.