What Is an LED Light Tube?
LED fluorescent lamp is commonly known as straight tube lamp, which is a substitute for traditional fluorescent tube, which is reflected in energy saving and environmental protection. The size installation method is the same as the traditional fluorescent lamp, but the light emitting principle is to use LED semiconductor chips to emit light. Divided into two types according to the shell material, one is glass, and the other is aluminum and PC. The luminous efficiency is 90lm / W ~ 200lm / W.
LED fluorescent light
LED fluorescent lamps are commonly known as straight tube lamps, which are alternatives to traditional fluorescent tubes.
The terminal voltage of the PN junction constitutes a certain potential barrier. When the forward bias voltage is applied, the potential barrier decreases, and the majority carriers in the P and N regions diffuse to each other. Since the electron mobility is much larger than the hole mobility, a large number of electrons will diffuse into the P region, constituting the injection of minority carriers in the P region. These electrons recombine with holes in the valence band, and the energy obtained during recombination is released in the form of light energy. This is how the PN junction emits light.
Classification according to LED fluorescent lamp diameter: T5, T8, T10, T12
Classification according to LED fluorescent lamp mask: diffuser and transparent cover (striped transparent cover)
Classification according to LED fluorescent lamp control function: conventional LED fluorescent lamp, sound-activated LED fluorescent lamp, infrared control LED fluorescent lamp, intelligent LED fluorescent lamp
1, environmental protection lamps, energy saving and environmental protection.
2, efficient conversion and reduce fever.
3. Quiet and comfortable, no noise.
4. The light is soft and protects the eyes.
5, no UV, no mosquitoes.
6. The voltage can be adjusted from 80V-245V.
7, save energy, longer life.
8, strong and reliable, long-term use.
9. Compared with ordinary fluorescent lamps, LED fluorescent lamps require no ballast, no starter, and no flicker.
10 Maintenance-free, frequent switching will not cause any damage.
11. Safe and stable quality can withstand 4kv high voltage and low heat dissipation, can work at low temperature -30 and high temperature 55 .
13. Good vibration resistance, easy to transport.
1. Installation: LED comes with constant current source, no ballast or starter is needed.
2. Voltage: AC 85V-AC 245V, all can work normally.
3. Heat dissipation: Prevent dust from covering the heat sink and affecting heat dissipation.
4. Waterproof: Because LED tube is composed of two parts: there is a gap in the connection, it is recommended to add a protective cover.
5. Vibration: LED fluorescent lamp has strong anti-vibration ability. As long as it is not a violent impact, it will generally not cause damage.
manufacturer
How to choose LED fluorescent lamp
LED fluorescent lamps are very professional, and most people don't know clearly. The following 5 tips tell you that you can choose LED lamps without instruments.
1. Look at the packaging and labels
Manufacturers of national mandatory products LED lighting marked the following on the packaging: rated voltage range, rated power, rated frequency. Under normal circumstances, print high-quality products with good quality, clear handwriting, and not easy to fall off. Wipe with a soft wet cloth, the logo is clearly distinguishable, the manufacturer's trademark and related certification marks.
2.Look at the appearance of the LED tube
Real LED fluorescent light. From the perspective of the lamp, the shape and size of the lamp are better and more consistent, the product consistency is good, and quality assurance is easier. Of course, there must be no cracks in the appearance and looseness between the interfaces. LED lamps must choose the engineering plastic flame retardant plastic PC shell. For ordinary plastic deformation and flammability, the aluminum tube must be bright, aviation aluminum.
3.Working temperature
During normal operation of LED fluorescent lamps, the temperature should be low. Otherwise, the life of the LED lamp is short. At the same time, when the energy-saving lamp is lit, it flashes rapidly or very harshly, which indicates that there is a quality problem in the energy-saving lamp. After a few minutes of power-on, there should be a temperature that proves that the heat is dissipated, and the aluminum substrate is used for heat dissipation. There is no temperature, it is a glass fiber board, and the heat cannot escape.
4, look at the startup performance
The LED fluorescent lamp has a characteristic to start: it lights up when it is powered on, and does not flicker.
5. Weighing weight, specific weight relative to each other, light weight is better, heavy explanation materials are better.
Advantages and disadvantages of fluorescent lamps
LED fluorescent lamps have become one of the earliest LED lamps to enter the room because they have many advantages over fluorescent lamps.
I. Advantages
Compared to fluorescent lamps, LED fluorescent lamps have 10 advantages:
1. High luminous efficiency: The luminous efficiency of fluorescent lamps is about 55-80 lm / W, while the luminous efficiency of LED is above 100 lm / W. In the future, it may reach 3 times.
2. High efficiency of lighting: The efficiency of lighting mainly refers to effective light efficiency. Because fluorescent lamps emit 360 degrees, fluorescent lamps usually use a white lampshade, which can reflect a considerable portion of the reverse light. Generally speaking, the efficiency of fluorescent lamps is only about 70%. The LED fluorescent lamp emits light at 120 degrees. And this light emitting angle can also be adjusted as needed.
3. High power efficiency:
Because all lamps require a special power supply except incandescent lamps, the efficiency of the power supply also affects the efficiency of the entire lamp.
The following takes the 36WT8 fluorescent lamp from Philips as an example. Its rated output power is 36W, but since the inductive ballast is connected, the measured input power is 42.4W, that is, the core inductor loses 6.4W, and the efficiency is reduced to 85%. Above 10W, the power factor is below 0.512. The power efficiency of LEDs is usually as high as 90%. An 18W LED fluorescent lamp requires only 20W of input power. The power factor can also reach above 0.9.
Compared with fluorescent lamps, it can save more than half of electricity, which means that using an 18-watt LED fluorescent lamp can replace a 36-watt fluorescent lamp.
4. Long life: The life of a carefully designed LED fluorescent lamp can reach 50,000 hours. The life of a fluorescent lamp is usually only 5,000 hours (some domestic fluorescent lamps have a life of only 300 hours). The difference between the two is almost 10 times.
5. Mercury-free and pollution-free: Fluorescent lamps contain mercury. A 36mm fluorescent lamp contains 25-45mg of mercury, and a 26mm (T8) contains 20mg of mercury. Fluorescent lamps use fragile glass as the shell. Once the glass is broken, the mercury in it will evaporate into the air immediately, and the mercury concentration in the surrounding air can reach 10-20 mg / m3 in an instant, exceeding national regulations. 1000-2000 times. Mercury is a toxic substance that is very harmful to the human body. When the mercury vapor reaches 0.04 to 3 mg, it will cause chronic poisoning in 2 to 3 months, and when it reaches 1.2 to 8.5 mg, it will induce acute mercury poisoning. Milligrams can directly cause animal death. And 1mg of mercury is enough to contaminate 5454.5 kg of drinking water, making it below the drinking standard. The LED fluorescent lamp does not contain any toxic substances and is a completely green and environmentally friendly light source.
6. Wide color temperature range: It can provide almost any color temperature, and it can also provide red, green, blue, or any color of light.
7. High color rendering index: The color rendering index of incandescent lamps is 95, fluorescent lamps are 65-80, and LED fluorescent lamps can be greater than 80.
8. No UV radiation.
9. Non-glass products, not easy to break, impact resistance, vibration resistance.
10. Safety in use: LED fluorescent lamps with external isolated power supply can not contact the high voltage of the city power at both ends of the tube, only DC safety voltage lower than 36V, there is no danger of electric shock.
2. Disadvantages
The only disadvantage of LED fluorescent lamps is the high price.
However, although the price of LED fluorescent lamp is about ten times that of fluorescent lamp, if it is related to its life, power saving and pollution-free, it is still cost-effective.
At present, most LED fluorescent lamps use surface-mounted lamp beads, low-power SMD lamp beads, divided into 5050, 3014, 3528, 2835, etc. The following analysis from the perspective of cost accounting-
Luminus 3014's market positioning is the highest cost performance, 3014 is 0.1w, normal brightness is 10-11LM, the maximum brightness is 12LM; and 3528, 0.06w, normal brightness is 7-8lm. The unit price of Luminus 3014 is about 0.23; the unit price of 3528 brightness at 7-8LM is about 0.19. Let's take an example: if an LED fluorescent lamp requires 1400LM, 3014 requires about 140, and 3528 requires about 200, the patch fee is about 0.018, and the total of the lamp beads and the patch fee:
3014 surface-mounted lamp beads LED fluorescent lamp cost = 0.23 × 140 + 0.018 × 140 = 34.72;
3528 surface-mounted lamp beads LED fluorescent lamp cost = 0.19 × 200 + 0.018 × 200 = 41.6;
From the above, it can be seen that using 3014 saves (41.6-34.72) /34.72=19.8% compared to using 3528. This part of the cost savings is considerable compared to the factory. By the same token, the cost of the LED fluorescent lamp using the 5050 patch is even lower, but the single lamp bead is too bright and dazzling.
3528 can achieve a light source efficiency of 130LM / W, and 3014 can achieve a light source efficiency of 110LM / W. Obviously, using 3528 lamp beads has more energy saving advantages. Some manufacturers use high-current methods to improve the efficiency of light sources, which often leads to serious consequences of shortening the life of the lamp.
In summary, generally speaking, under the condition of the same luminous flux of the entire LED fluorescent lamp, the brighter the single lamp bead, the lower the cost; in terms of visual comfort, the number of lamp beads can be more than 100, and too much is meaningless. . Judging from the current technology development potential, it is difficult to obtain good visual effects for LED fluorescent lamps using high-power lamp beads. Only using low-power lamp beads, there are two options: 3014 and 3528. 3014 is cheaper and 3528 is more power-efficient. See if users are more inclined to price or more power saving rate, after all, it is difficult to have both fish and bear's paw.
(1) Purchase three elements
1. Technology: imported chip lamp beads + constant current source driver + heat dissipation packaging process;
2. Price: High quality is bound to high price, low price is bound to high light decay;
3. Selection: It is recommended to choose a high-end flagship version for export; it is recommended to choose our mid-range products for long-term lighting venues such as factories, supermarkets, and hospitals;
(Two) LED life
LED lamp life refers to the time when the luminous brightness of the led lamp beads drops to 50%. The imported chip lamp beads generally have 70,000 hours and a damaged life of 100,000 hours. The life of the entire LED lamp includes the life of the lamp beads and the life of the driving system. ~ 30000 hours, the life of non-genuine whole lamp is difficult to guarantee.
(Three) LED zero light attenuation
The light decay of LED lamps will inevitably occur. Zero light decay does not exist, it is only a matter of size.
(D) LED cost performance
The biggest advantage of led lamps is energy saving and durability. Energy saving is the essential characteristics of LED chips. Durability is mainly the control of light decay. The key factor affecting light decay is: first of all, the chip is itself. The price is low; followed by constant current driving, the LED lamp is very sensitive to the heat of the LED chip, and the constant temperature driving can be used to control the chip heating and the heating to control the light decay. The packaging process has high heat dissipation requirements, and the manufacturing process is also very important. The above three factors have achieved the quality of the LED and also determined its high price, the so-called "high quality and high price, low price and high light attenuation".
(5) Comparison of LED fluorescent lamp and traditional fluorescent lamp
1. Energy saving benefits
product | LED-T10 tube | 40W energy-saving fluorescent tube |
Number of light pipes | 1000 | 1000 |
power | 16 | 46 |
Power saving rate | 65.2% |
Electricity time per day | twenty four | twenty four |
Electricity price | 1 | 1 |
Annual total electricity consumption (kWh) | 140.160 | 402.960 |
Amount of electricity used per year | 140.160 | 402.960 |
Monthly electricity bill | 11.68 | 33.58 |
Daily electricity bill | 0.384 | 1.104 |
Save electricity bills every year | 262.80 |
Save electricity bills every month | 21.90 |
Save electricity every day | 0.72 |
Annual savings ratio | 65.2% |
2. Economic benefits
Year of power saving | First year (2010) | The second year (2011) | The third year (2012) |
Single lamp saves electricity bills every day | 0.72 | 0.72 | 0.72 |
Counting days | 365.00 | 365.00 | 365.00 |
Single lamp daily income | 0.27 | 0.27 | 0.27 |
Income ratio | 0.38 | 0.38 | 0.38 |
Number of lamps | 1000.00 | 1000.00 | 1000.00 |
Amount of electricity saved | 98550.00 | 98550.00 | 98550.00 |
total | 295650.00 |
3. Analysis of payment expenses
Year of payment | First year (2010) | The second year (2011) | The third year (2012) |
Single lamp saves electricity bills every day | 0.72 | 0.72 | 0.72 |
Counting days | 365.00 | 365.00 | 365.00 |
Single tube rental per day | 0.45 | 0.45 | 0.45 |
Rent collection ratio | 0.63 | 0.63 | 0.63 |
Number of lamps | 1000.00 | 1000.00 | 1000.00 |
Payment amount | 164250.00 | 164250.00 | 164250.00 |
total | 492750.00 |
(6) LED power configuration scheme
1. Why must the LED fluorescent lamp power supply be constant current?
The semiconductor characteristics of LEDs determine that they are greatly affected by the environment. For example, temperature, LEDs are current-sensitive components. Increasing the current of LEDs will directly increase the heating. Working for longer than the rated current for a long time will cause the LED chip to be at a high temperature for a long time. Shorten the life of LED. The LED constant current power supply can ensure that its operating current does not change when the voltage and other factors change, thereby protecting the LED chip from high temperature damage. It is so-called-the power supply is easy to destroy.
2. How can the LED fluorescent lamp power supply match the lamp board?
The voltage is too small (such as I> 350mA, V <40V); or the current is too small and the voltage is too high (such as I180V), resulting in severe fever, low efficiency, or insufficient input voltage range. Choose a suitable serial and parallel connection method, the voltage and current applied to each LED lamp bead are the same.
3. What is the most suitable working current for the LED fluorescent lamp power supply?
General LED lamp beads have a rated working current of 20 mA. After several comparative tests, it is ideal to design it to 17 to 19 mA. The recommended design is 18 mA, which can ensure that the life of the product is much longer than similar products. Although the cost will increase by a few percentage points.
4. What is the working voltage of the LED fluorescent lamp power supply?
The recommended working voltage of general LED lamp beads is 3.0-3.5V, the total voltage of M lamp beads connected in series = 3.125 × M
5. How wide is the series and parallel and wide voltage of the LED lamp board?
Generally, LED fluorescent lamps need to adapt to a wide range of input voltage, such as AC85 265V, so the series and parallel mode of LED lamp beads on the board is very important. The output voltage should not exceed 72V, and the input voltage range can reach 85 265V. That is, the number of concatenations does not exceed 23 strings. Do not connect too many in parallel, otherwise the working current is too large and the heat is serious, it is recommended to be 6 and / 8 and / 12. The total current does not exceed 240 mA. There is also a wide voltage solution, which is to first increase the voltage to 400V with L6561 / 7527, and then step down, which is equivalent to two switching power supplies, which is twice as expensive. This solution is not cost-effective and there is no market.
6.Relationship between series and parallel and PFC power factor and wide voltage
There are three cases of power supply PFC on the market: one is without PFC dedicated circuit, its PFC is generally around 0.65; one is with passive PFC circuit, the lamp board is well prepared, and the PFC is generally around 0.92; it is also used One is made by active active 7527/6561 circuit, PFC can reach 0.99; the third solution costs twice as much as the second solution, so there are more LED fluorescent lamp manufacturers who choose the second solution. For passive PFC circuits: also known as valley-filled PFC circuits, the operating voltage range is half the peak value of the AC input voltage. If the input is 180V, its peak is 180 × 1.414 = 254V, half of the peak voltage is 127V, and minus the step-down voltage drop of 30V, the maximum output is 90V, so the maximum number of LED lamp beads in series is 28 strings. Therefore, in order to obtain a relatively large power factor, the number of lamp beads in series should not be too much, otherwise, the requirements of low voltage cannot be achieved.
7. What is the most suitable constant current accuracy of LED fluorescent lamp power supply?
The constant current error is generally required to be ± 3%. The constant current accuracy of some power supplies on the market is too poor. Constant current solutions such as the popular PT4107 / HV9910 / BP2808 / SMD802 solutions on the market have an error of ± 8% or ± 10%, and the constant current error is too large. According to the 3% error, 6 channels are connected in parallel, and the error of each channel is about ± 0.5%. If 12 channels are connected in parallel, the error of each channel is about ± 0.25%, which is enough accuracy. If the accuracy is too high, the cost will increase significantly. And for LED lamp beads, the difference between 17 mA and 17.5 mA is not too great.
8.Isolated / non-isolated
Generally, if the isolated power supply is made into 15W and placed in the LED tube, its transformer is very large and difficult to put in. Especially for T6 / T8 lamps, it is almost impossible, so the isolation can generally only achieve 15W, rarely more than 15W, and the price is very expensive. Therefore, the cost-effectiveness of isolation is not high. Generally, non-isolation has more mainstream, and the volume can be made smaller, and the minimum can be 8 mm high. In fact, non-isolated security measures are in place, and there is no problem.
9, LED fluorescent lamp power efficiency
Output efficiency = voltage of output LED × output current / input power. This parameter is important because a major selling point of LED fluorescent lamps is energy saving. In addition, if the power supply efficiency is low, a large amount of heat will be emitted in the tube, which will cause the temperature of the power supply to increase after temperature equilibrium. In addition, the heat from the power supply will also increase the temperature of the LED chip, which will cause the light decay of the LED fluorescent lamp, and eventually lead to a shortened life of the entire product. In summary, power efficiency is an important factor in determining the life of LED fluorescent lamps. Generally, it is OK if it is above 80%. In addition, efficiency is also related to the matching method of the lamp board.
10, LED fluorescent lamp power supply size
Height is the main limiting factor. Generally, the size for T6 tube / T8 requires that the height should not be too high 9 mm. The height of the T10 tube is 15 mm. The length can be longer, making it easier to dissipate heat.
11. Thoughts on extending the life of LED fluorescent lamp power supply
First, choose a power supply with a longer life; second, use an external power supply; third, choose a plug-and-swap built-in power supply. From "How Long Is the Popularization of LED Fluorescent Lamps"
Ordinary fluorescent lamps have a filament at each end. The tube is filled with traces of argon and thin mercury vapor. The inner wall of the tube is coated with fluorescent powder. When the gas between the two filaments conducts electricity, it emits ultraviolet light, which makes the fluorescent powder soft. Visible light.
The operating characteristics of ordinary fluorescent lamps: a high voltage is required when the lamp starts to ignite, and only a small current is allowed to pass during normal lighting. At this time, the voltage across the lamp is lower than the power supply voltage.
An ordinary fluorescent tube is equipped with a filament at both ends, and the inner wall of the glass tube is coated with a thin layer of uniform fluorescent powder. After the tube is evacuated to a vacuum of 10-3-10-4 mm Hg, it is filled with a small amount of inert gas, and a small amount of liquid is injected at the same time. mercury. An inductive ballast is an iron core inductor coil. The nature of the inductor is that when the current in the coil changes, it will cause a change in the magnetic flux in the coil, which will generate an induced electromotive force, which is opposite to the direction of the current, thus hindering it. Current change.
The starter acts as a switch in the circuit. It consists of a neon discharge tube and a capacitor in parallel. The capacitor's role is to eliminate electromagnetic interference to the power supply and form a vibration circuit with the ballast to increase the start pulse voltage amplitude. . An electrode in the discharge tube is composed of a bimetallic piece. The neon bubble discharge is used to heat the bimetallic piece when the bimetallic piece is opened and closed, causing a sudden change in the current of the inductive ballast and generating a high voltage pulse to the two ends of the lamp.
After the ordinary fluorescent lamp is connected to the circuit, a glow discharge starts between the two electrodes of the starter, which causes the bimetal to expand and contact the static contact electrode. The power supply, ballast, filament, and starter form a closed loop. The electric current preheats the filament. When the heating time is 1-3 seconds, the glow discharge between the two electrodes of the initiator is extinguished, and the bimetal is cooled and disconnected from the static contact. When the two electrodes are disconnected, Instantly, the current in the circuit suddenly disappeared, so the ballast produced a high-voltage pulse, which was superimposed with the power supply and added to the two ends of the lamp tube, causing the inert gas in the lamp tube to ionize and cause arc discharge. During normal light emission, The self-inductance of the ballast also plays a role in stabilizing the current in the circuit. [1]
