LED lighting production

0805 yellow light LED patch LED LED

In the use of electric energy, lighting power accounts for a considerable proportion. The fluorescent lamps and energy-saving lamps that we use nowadays have greatly improved the luminous efficiency compared with the earlier ordinary incandescent lamps, and have obtained a wide range of application. As the level of manufacturing technology continues to increase, LEDs (light-emitting diodes) are also widely used in various lighting fields.

LEDs have higher luminous efficiency, lower power consumption and longer service life, and have achieved very good results in urban lighting projects and home lighting. In the current energy shortage environment, LED energy-saving technology will become a very important development direction. Our country has launched the "Semiconductor Lighting" project to develop and promote it as a new generation of green lighting sources.

First, the advantages of LDE lighting

1. High luminous efficiency

After decades of technological improvements, LEDs have greatly improved their luminous efficiency. The incandescent lamp and tungsten halogen have a luminous efficiency of 12~24 lumens/watt, the fluorescent lamp is 50~70 lumens/watt, and the sodium lamp is 90~140 lumens/watt. Most of the power consumption becomes heat loss. After the LED light effect is improved, it will reach 50~200 lumens/watt, and its light has good monochromaticity and narrow spectrum. It can directly emit colored visible light without filtering. At present, all countries in the world are doing research on improving LED light efficiency, and their luminous efficiency will be greatly improved in the near future when they assemble LED lighting.

2. Low power consumption

The LED is driven by DC. The single-tube driving voltage is 1.5~3.5V, the current is 10~18mA, the reaction speed is fast, and it can work at higher frequency.

In the case of the same lighting effect, the power consumption is about one tenth of that of an incandescent bulb, which is about one third of a fluorescent tube. Take the bridge guardrail lamp as an example. The same effect of a fluorescent lamp with ballast loss consumes more than 40 watts of power, and the power of each LED is only 10~15W, no ballast is needed, and it can change colorfully.

3. Long service life

The use of electronic light field radiation, the filament is easy to burn, thermal deposition, light attenuation and other shortcomings. The LED lamp is small in size, light in weight and epoxy resin package, and can withstand high-strength mechanical shock and vibration, and is not easily broken. LEDs have an average life of 100,000 hours. The ordinary white LED used for illumination has an effective service life of more than 20,000 hours, and the special illumination LED known as zero light decay has a longer life. The service life of LED lamps can reach 5~10 years, which can greatly reduce the maintenance cost of lamps and avoid the pain of frequent lamp replacement.

4. Strong safety and reliability

Low calorific value, no heat radiation, cold light source, can control light type and illuminating angle, soft light color, no glare; no mercury, sodium and other substances that may be harmful to health.

5. Conducive to environmental protection

The LED is an all-solid illuminant, which is resistant to shock and impact, and can be recycled without waste. The light source is small in size and can be combined at will. It is easy to develop into a light, thin and short lighting product, and is also easy to install and maintain. Of course, energy saving is the most important reason for us to consider the use of LED light sources. Maybe LED light sources are more expensive than traditional light sources, but we can recover the investment of light source with energy saving for one year, so we can get several times of energy saving net income every year for 4~9 years. .

Second, the production of LED lighting

Here to introduce you to the production of an LED lighting, we first get a general understanding of the characteristics of white LED. This kit uses a 5mm diameter straw hat white LED, as shown in Figure 1. The rated voltage of each LED is 3.0~3.2V, the brightness is 1400~1600mcd, and the rated working current is 20mA. When the working current is smaller, the luminous efficiency is higher, the temperature rise is lower, and the effective light source life can be 2 More than 10,000 hours. (Because the use time increases, the LED will gradually decrease the brightness due to the light decay. The effective light source life refers to the accumulated working time of the LED that can emit effective and valuable light when working. After this time, the LED can still be Bright, but the brightness is too low, thus losing practical value.) The life of ordinary energy-saving lamps is only about 5,000 hours, and the life of ordinary incandescent bulbs is only about 1,000 hours. From the cost of replacing the bulbs and the electricity saved, Using LED lights is still very cost effective.

Figure 1 straw hat head white LED shape

The finished LED lamp is shown in Figure 2. The measured power consumption of the full lamp is about 3.3W. After lighting, it is roughly equivalent to the brightness of a 40W incandescent lamp, which is equivalent to the brightness of a 7-9W energy-saving lamp. It is continuously lit for 24 hours and consumes less than 0.08 degrees of power consumption, which has significant energy saving effect. The E27 size threaded port is the same as the ordinary incandescent lamp at the bottom of the lamp for easy installation. The use of a frosted lampshade ensures high light transmission while also making the LEDs glare when looking directly at the LED. This LED light is suitable for use as a lighting in places where desks, bedsides, kitchens, bathrooms, public corridors, etc. are not too large.

Figure 2 finished LED lights

The circuit schematic is shown in Figure 3. The 220V mains first passes through C1 and R2 to resist the voltage drop, in which R2 is the bleeder resistor and C1 is the step-down capacitor. After the withstand voltage is 400V, the DC output is output through the W1 rectifier bridge, and then the R4 current limit is sent to 60 LEDs connected in series. Because the load of the resistor-capacitor-connected LED is not a pure resistor, but the characteristics of the voltage regulator are similar. According to the principle parameter selection component, the current flowing through the LED is about 13 mA. C2 is a filter capacitor. Prevents the impact of large currents on the LED at the moment of turning on the light. R1 is an NTC thermistor. When an unexpected current condition occurs in the circuit, the resistance increases, which causes the current to decrease and thus protects.

Figure 3 circuit schematic

The main components of the LED lamp are shown in Figure 4. The LED is equipped with 60+2, of which 2 are just spare parts. The component of the circular plate of the soldered LED is white painted to increase the reflective effect. For the convenience of the user, the 220V lead wire inside the threaded port is crimped by a special tool when it is shipped from the factory, which can prevent the lead wire from falling off and causing an accident.

Figure 4 Main components of the LED lamp

The assembly begins below, and the LED panel can be soldered first. The long pin of the LED is the positive terminal and the short pin is the negative terminal. The shaded end of the LED symbol on the circular plate is the negative pole. Because LED is a high-sensitivity electronic component with low voltage and low current, white LED is very sensitive to static electricity. If it is damaged by static electricity, it will show some bad characteristics, such as increased leakage current, no light or abnormal illumination during testing, so when soldering Be sure to do anti-static protection. The operator should wear an anti-static wrist strap to prevent damage to the LED caused by static electricity. To select a 30W tip soldering iron that does not leak electricity, you can first solder the LED to observe the position of the LED. If it is not correct, you can correct the position of the solder and confirm the position is correct before soldering the other pin. The welding should be carried out simply and decisively. The welding time should not be too long. It should be controlled within 2 seconds, otherwise the LED may be welded. The control symbols are used to weld the LEDs on a circular plate. The appearance of the solder is shown in Figure 5.

Figure 5 welded appearance

Next, the driver board is soldered, and the empty board is shown in Figure 6. The components are soldered to the driver board according to the component numbers of the schematic diagram. The soldered driver board is shown in Figure 7.

Figure 6 empty board diagram

Figure 7 welded driver board diagram

Then connect the screw, the drive board and the LED light board with wires, and connect the middle lead of the screw to the C1 of the drive board. The lead of the thread part is connected with R1. The driver board outputs "+" and "-" respectively to the "+" and "-" of the LED panel. Note that the output leads of the driver board must first pass through the holder and then connect to the LED panel.

As shown in Figure 8.

Figure 8

The driving plate is loaded into the lamp body, and the four corners of the driving plate are fixed to the lamp body by a hot melt glue gun. Users who do not have a hot melt glue gun can cut the rubber block in the kit into four small pieces and heat the rubber block with a soldering iron to fix the drive plate. Then, the fixing frame is loaded into the lamp body, and the fixing frame is rotated along the groove in the lamp body so that the four wings of the fixing frame just enter the groove. As shown in Figure 9.

Figure 9

Fasten the screw to the holder through the middle hole of the LED panel, as shown in Figure 10.

Figure 10

Finally, the frosted lampshade is buckled and the LED is made. As shown in Figure 11.

Figure 11

By installing the assembled LED lamp on a common screw socket, you can enjoy the different experience brought by the new energy-saving and environmentally friendly lamps.

Tip: With dimming, voice control, and other screw sockets with thyristor control, it is not suitable for direct installation of this LED.

Component list

Third, on the light decay of LED

The so-called light decay means that after a period of use of the illuminant, the luminous efficiency decreases, and the brightness is not as high as the initial time. The luminaire standard calculates the light decay according to 1000 hours, that is, the luminous efficiency decreases after 1000 hours of continuous or continuous operation. Percentage, we usually know very well that household lighting will have light decay after using for a period of time. Energy-saving lamps and fluorescent lamps will have light decay. Generally, the energy-saving lamps and fluorescent lamps we use will be brighter than the initial one after using for a period of time. The time is much lower, until the end of the service life, the brightness will always drop straight, and the energy-saving lamps and fluorescent lamps will be darker and darker. According to the quality standards of energy-saving lamps, the ordinary energy-saving lamps should maintain less than 5% light decay after 1000 hours of use, which means that the ordinary energy-saving lamps should reach more than 95% of the initial brightness after 1000 hours of use. Therefore, the light decay of energy-saving lamps is closely related to the quality of energy-saving lamps. After many years of history of energy-saving lamps, I believe that everyone has found that low-cost energy-saving lamps are generally not used after one year. The energy-saving lamps of good quality brands have not changed in brightness even after three years and five years. This is enough to prove that the light decay of the luminaire is fully reflected in the quality of the luminaire.

The reason why the illuminant has light decay is that the material of most illuminators is aging after a long period of work. Any illuminating material needs energy supply during operation. The most commonly used energy is electric energy. The bulb we use. All of them are converted into heat and light energy, which means that any light-emitting element will generate heat. Therefore, the material will age under the long-term high temperature, and the aging of the material will directly affect the light-emitting material. Efficiency, we usually find that fluorescent tubes and fluorescent lamps use a long time, the phosphor will be black, which means that the phosphor is aging, the more severe the aging, the lower the luminous efficiency, the greater the light decay, so the light should be controlled. The speed of decay should choose high-quality illuminating materials and components, as well as the temperature of the illuminating material should be controlled as much as possible in the circuit design. The temperature control of the illuminating material will also play a significant role in reducing the light decay.

LEDs are solid-state semiconductor devices that convert electricity directly into light. The heart of the LED is a semiconductor wafer with one end of the negative electrode and the other end connected to the positive terminal of the power supply, so that the entire wafer is encapsulated by epoxy resin. The semiconductor wafer consists of three parts, one part is a P-type semiconductor, in which the hole dominates, and the other end is an N-type semiconductor, where it is mainly electron, and the middle is usually a quantum well of 1 to 5 cycles. When a current is applied to the wafer through a wire, electrons and holes are pushed into the vector sub-well. In the quantum well, the electrons recombine with the holes, and then the energy is emitted in the form of photons, that is, the light we need. The wafer will also generate temperature during operation. The long-term temperature rise will cause the wafer to age, the aging of the wafer will decrease, and the luminous efficiency will decrease, which will cause the LED to have a light decay.

LED light decay control LED has many reasons for light decay. The main factor is the aging of the chip. The most important thing to solve the light decay is to control the aging speed of the LED chip. First of all, the quality of the LED chip is very important, and it is the solution. The problem of heat dissipation from the chip is also critical. In short, the factors that solve the problem of LED light decay are various, and the quality of the wafer and the choice of packaging technology packaging materials are all critical.

LED light decay and life LED is characterized by long life and theoretical life of 8 to 100,000 hours. Of course, some people have expressed doubts. Can LED really achieve such a long life? According to such life, LED lamps can be used. Is it not bad for decades? According to the laboratory, the so-called life of 8 to 100,000 hours is a prerequisite. The LED chip, the environment used, the current used, etc. have a direct relationship. Refers to the time required for the LED to completely lose electrical performance from the beginning of use, of course, does not take into account the factors of light decay. What we need in lighting applications is the illuminating life, that is, the effective light source life. The effective light source life refers to the cumulative working time of the LEDs that can effectively emit useful light when working. The LED usually has an effective light source life of 3~5. Ten thousand hours is already good. Therefore, the speed of LED light decay is inversely proportional to the life of the LED. Only when the light decay is controlled, the long life is truly achieved.