Detailed explanation of basic knowledge points related to LED fluorescent lamps

LED fluorescent lamp

LED fluorescent lamps use ultra-bright LED white light as the light source, and the shell is acrylic/aluminum alloy. The outer cover can be made of PC tube, which can withstand high temperatures up to 135 degrees. LED fluorescent lamps are the same as traditional fluorescent lamps in terms of appearance, size and diameter. There are three lengths of 60cm, 120cm and 150cm, and the power is 10W, 16W and 20W respectively. The actual power consumption of a 20W traditional fluorescent lamp (inductive ballast) is about 53W, and the actual power consumption of a 40W traditional fluorescent lamp (inductive ballast) is about 68W.

LED fluorescent lamp T8

[1]Definition:

The brightness of 10W LED fluorescent lamp is brighter than traditional 40W fluorescent lamp, and 16W LED fluorescent lamp is brighter than traditional 64W fluorescent lamp. The brightness of LED fluorescent lamp is especially softer and easier for people to accept. The service life is 50,000-80,000 hours. The power supply voltage is AC85V-260V (AC). No starter and ballast are required. It starts quickly, has low power, no flicker, and is not easy to cause visual fatigue. It is not only super energy-saving but also environmentally friendly. It is one of the key products developed by the national green energy-saving lighting project and is currently the main product to replace traditional fluorescent lamps.

LED fluorescent lamps are relatively simple to install. They are divided into two types: internal power supply and external power supply. When installing LED fluorescent lamps with internal power supply, remove the original fluorescent lamps and replace them with LED fluorescent lamps, and remove the ballast and starter, so that 220V AC mains power is directly added to both ends of the LED fluorescent lamp. LED fluorescent lamps with external power supply are generally equipped with special lamp holders, which can be used after replacing the original ones.

LED fluorescent lamps save more than 80% of electricity, and their lifespan is more than 10 times that of ordinary lamps. They are almost maintenance-free, and there is no need to frequently replace lamps, ballasts, and starters. The cost can be recovered in about half a year. Green and environmentally friendly semiconductor electric light sources have soft light and pure spectrum, which is beneficial to workers' vision protection and health. The 6000K cold light source gives people a visually cool feeling, which helps to concentrate and improve efficiency.

Luminous principle:

The terminal voltage of the PN junction forms a certain potential barrier. When a forward bias voltage is applied, the potential barrier drops, and the majority carriers in the P region and the N region diffuse toward each other. Since the electron mobility is much greater than the hole mobility, a large number of electrons will diffuse toward the P region, forming an injection of minority carriers in the P region. These electrons recombine with holes in the valence band, and the energy obtained during the recombination is released in the form of light energy. This is the principle of PN junction luminescence.

Luminous efficiency:

It is generally called the external quantum efficiency of the component, which is the product of the internal quantum efficiency of the component and the extraction efficiency of the component. The so-called internal quantum efficiency of the component is actually the electro-optical conversion efficiency of the component itself, which is mainly related to the characteristics of the component itself (such as the energy band, defects, impurities of the component material), the crystal composition and structure of the component, etc. The extraction efficiency of the component refers to the number of photons generated inside the component that can be measured outside the component after being absorbed, refracted, and reflected by the component itself. Therefore, the factors related to the extraction efficiency include the absorption of the component material itself, the geometric structure of the component, the refractive index difference between the component and the packaging material, and the scattering characteristics of the component structure. The product of the internal quantum efficiency of the component and the extraction efficiency of the component is the luminous effect of the entire component, that is, the external quantum efficiency of the component.

The early development of components focused on improving their internal quantum efficiency. The main method was to improve the quality of the stacked crystal and change the structure of the stacked crystal, so that electrical energy is not easily converted into heat energy, thereby indirectly improving the luminous efficiency of the LED, so that a theoretical internal quantum efficiency of about 70% can be obtained. However, such internal quantum efficiency is almost close to the theoretical limit. Under such circumstances, it is impossible to increase the total amount of light of the component by simply improving the internal quantum efficiency of the component, so improving the extraction efficiency of the component has become an important research topic. The current methods are mainly: changes in the appearance of the grains--TIP structure, surface roughening technology.

Electrical characteristics:

Current-controlled devices, load characteristics are similar to the UI curve of PN junctions. A very small change in forward conduction voltage will cause a large change in forward current (exponential level), the reverse leakage current is very small, and there is a reverse breakdown voltage. In actual use, it should be selected. The forward voltage of LED decreases with increasing temperature and has a negative temperature coefficient. LED consumes power, part of which is converted into light energy, which is what we need. The rest is converted into heat energy, which increases the junction temperature. The heat (power) dissipated can be expressed as.

Optical properties:

LED provides monochromatic light with a large half-width. Since the energy gap of the semiconductor decreases with the increase of temperature, the peak wavelength it emits increases with the increase of temperature, that is, the spectrum red shifts, and the temperature coefficient is +2~3A/. The LED luminance L is approximately proportional to the forward current:, K is the proportional coefficient. As the current increases, the luminance also increases approximately. In addition, the luminance is also related to the ambient temperature. When the ambient temperature is high, the recombination efficiency decreases and the luminous intensity decreases.

Thermal properties:

Under low current, the temperature rise of LED is not obvious. If the ambient temperature is high, the main wavelength of LED will be red-shifted, the brightness will decrease, and the uniformity and consistency of light emission will deteriorate. In particular, the temperature rise of dot matrix and large display screens has a more significant impact on the reliability and stability of LED. Therefore, heat dissipation design is critical.

life:

Long-term operation of LEDs will cause light decay and aging, especially for high-power LEDs, the light decay problem is more serious. When measuring the life of LEDs, it is far from enough to use the damage of the lamp as the end of the LED life. The LED life should be specified by the percentage of light decay of the LED, such as 35%, which is more meaningful.

LED fluorescent lamp features

LED fluorescent lamps are characterized by high quality, durability, and energy saving. They have a wide range of projection angle adjustment. The brightness of 15W is equivalent to that of ordinary 40W fluorescent lamps. They are resistant to high temperatures, moisture, water, and leakage. The operating voltage is optional: 110V or 220V. The outer cover can be made of glass or PC. The lamp holder is the same as that of ordinary fluorescent lamps.

LED fluorescent lamps use the latest LED light source technology and digital appearance design, which can save more than 70% of electricity. The light intensity of 12W LED fluorescent lamps is equivalent to that of 40W fluorescent tubes. The life of LED fluorescent lamps is more than 10 times that of ordinary tubes. They are almost maintenance-free and do not require frequent replacement of tubes, ballasts, and starters. Green and environmentally friendly semiconductor electric light sources have soft light and pure spectrum, which is beneficial to the user's vision protection and physical health. The 6000K cold light source gives people a visually cool feeling, and the humanized illumination difference design is more conducive to concentration and improved efficiency.

1. Strong applicability, with improved adaptability and reliability in various harsh environments indoors and outdoors

2. Rich colors: It is composed of three primary colors (red, green, blue) display unit box, so that the electronic screen can display dynamic images with rich colors, high saturation, high resolution and high display frequency.

3. High brightness: Using ultra-high brightness LED, it is still clearly visible at a long distance under strong sunlight.

4. Good effect: Using nonlinear correction technology, the image is clearer and the layering is stronger

5. Strong reliability: Adopting static scanning technology and modular design technology, it has higher reliability and stability

6. Diversified display modes: supports multiple display modes.

Characteristics of ordinary fluorescent lamps

An ordinary fluorescent lamp has a filament at each end. The lamp tube is filled with a trace amount of argon and a thin mercury vapor. The inner wall of the lamp tube is coated with fluorescent powder. The gas between the two filaments emits ultraviolet light when conducting, causing the fluorescent powder to emit soft visible light.

Working 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.

Ordinary fluorescent tubes are equipped with filaments at both ends, and the inner wall of the glass tube is coated with a uniform thin layer of fluorescent powder. After the tube is evacuated to a vacuum degree of 10-3-10-4 mmHg, a small amount of inert gas is filled in, and a small amount of liquid mercury is also injected. The inductor 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, thereby generating an induced electromotive force, the direction of which is opposite to the direction of the current, thus hindering the change of the current.

The starter acts as a switch in the circuit. It consists of a neon discharge tube and a capacitor in parallel. The capacitor is used to eliminate electromagnetic interference to the power supply and form an oscillation circuit with the ballast to increase the voltage amplitude of the starting pulse. One electrode in the discharge tube is composed of a bimetallic strip. The neon bulb is used for discharge heating. When the bimetallic strip is opened and closed, it causes a sudden change in the current of the inductive ballast and generates a high-voltage pulse to be applied to both ends of the lamp tube.

When an ordinary fluorescent lamp is connected to the circuit, glow discharge begins between the two electrodes of the starter, causing the bimetallic strip to expand due to heat and contact with the static contact electrode. The power supply, ballast, filament and starter then form a closed loop. The current preheats the filament. After 1-3 seconds of heating, the glow discharge between the two electrodes of the starter goes out, and the bimetallic strip cools and disconnects from the static contact electrode. At the moment the two electrodes are disconnected, the current in the circuit suddenly disappears, and the ballast generates a high-voltage pulse, which is superimposed on the power supply and added to both ends of the lamp tube, ionizing the inert gas in the lamp tube and causing arc discharge. During normal lighting, the self-inductance of the ballast also plays a role in stabilizing the current in the circuit.

By comparing the properties of LED fluorescent lamps with those of ordinary fluorescent lamps, we can draw the following conclusions:

LED fluorescent lamps have the following advantages compared with ordinary fluorescent lamps:

Energy saving, long life, good applicability, due to the small size of a single LED, can be made into any shape, short response time, environmental protection, no harmful metals, easy recycling of waste, colorful, pure luminous color, narrow spectrum range, and can mix the three primary colors of red, green and blue into colorful or white light.

Compared with ordinary fluorescent lamps, LED fluorescent lamps have the following disadvantages: expensive price, there is still a big gap between the currently generally achievable light efficiency and the theoretical light efficiency, there is still a big gap between the currently achievable lifespan and the theoretical lifespan, there is still a certain amount of heat generation, and the light decay can be greatly reduced.

advantage:

1. Environmentally friendly lamps protect the earth

Traditional fluorescent lamps contain a lot of mercury vapor, which will evaporate into the atmosphere if broken. However, LED fluorescent lamps do not use mercury at all, and LED products do not contain lead, which protects the environment. LED fluorescent lamps are recognized as green lighting in the 21st century.

2. Efficient conversion, reducing heat

Traditional lamps generate a lot of heat, while LED lamps convert all electrical energy into light energy, which does not cause energy waste. In addition, they do not cause fading of documents and clothes.

3. Quiet and comfortable, no noise

LED lamps do not produce noise and are the best choice for places where precision electronic instruments are used. They are suitable for places such as libraries and offices.

4. Soft light, protect your eyes

Traditional fluorescent lamps use alternating current, so they flicker 100-120 times per second. LED lamps convert alternating current directly into direct current, which does not flicker and protects your eyes.

5. No UV rays, no mosquitoes

LED lamps do not produce ultraviolet rays, so unlike traditional lamps, there will not be many mosquitoes around the light source. The room will become cleaner and tidier.

6. Voltage adjustable 80V-245V

Traditional fluorescent lamps are lit by the high voltage released by the rectifier, and cannot be lit when the voltage is reduced. However, LED lamps can be lit within a certain range of voltage and the brightness can be adjusted.

7. Save energy and extend life

The power consumption of LED fluorescent lamps is less than one-third of that of traditional fluorescent lamps, and their lifespan is 10 times that of traditional fluorescent lamps. They can be used for a long time without replacement, reducing labor costs. They are more suitable for occasions where replacement is difficult.

8. Sturdy and reliable, suitable for long-term use.

The LED lamp body itself is made of epoxy resin instead of traditional glass, which is more solid and reliable. Even if it falls on the ground, the LED will not be easily damaged and can be used with confidence.

9. Compared with ordinary fluorescent lamps, LED fluorescent lamps do not require ballasts, starters, and have no flicker.

10. Maintenance-free, frequent switching will not cause any damage.

11. It is safe and has stable quality. It can withstand 4kv high voltage and has low heat dissipation. It can work at low temperature of -30℃ and high temperature of 55℃.

12. It will not have any impact on the surrounding environment. There is no ultraviolet and infrared rays, no harmful materials such as mercury, protect the eyes, and no noise.

13. Good vibration resistance and easy to transport.

Material composition and appearance

1. LED fluorescent lamps are composed of multiple ultra-bright low-power LEDs, a highly light-transmitting PC cover, heat-dissipating aluminum parts and a power supply.

2. The light sources used in LED fluorescent lamps include straw hat head and SMD lamp beads.

Among them, the commonly used SMD lamp beads are 3528, 5050, 1W high power, etc.

3. There are two types of LED fluorescent lamp shells:

1) Transparent PC shell, high light transmittance, you can see the lamp beads inside;

2) The translucent frosted shell allows for softer light transmission.

4. The LED fluorescent lamp has a built-in power supply and a wide operating voltage range, from 85V to 265V.

5. LED fluorescent lamps can be made into red, yellow, blue, green, white and warm white colors.

Basic Specifications

T5: Current LED T5 lamp specifications

T8: Current T8 specifications

Scope of application:

Indoor lighting for office buildings, factories, shopping malls, schools, homes, etc.