COB light source is sensitive to static electricity, so effective protective measures must be taken when using COB light source. In particular, the high voltage current generated by static electricity exceeds the maximum rating of the product, which will cause damage to the product, or may make the product completely ineffective. When using the product, the customer shall take safe measures to prevent static electricity and power surge. Grounding resistance ≤10 OhMs.
The use of anti-static wristbands, anti-static MATS, anti-static overalls and work shoes, gloves and anti-static containers are effective measures to prevent static electricity and power surges, and the soldering iron point should be correctly grounded.
Manual welding with soldering iron:
It is recommended to use less than 20W soldering iron, and the temperature of the soldering iron must be maintained not higher than 300 ° C, and the welding time is not more than 3 seconds.
(a) Set according to the standard temperature curve.
(b) After the welding is completed and the temperature of the product has dropped to room temperature, carefully handle the product.
Excellent heat dissipation performance
LED interface temperature plays a key role in LED life and performance, lower interface temperature due to lower deterioration, so longer life, in addition, LED at lower temperature, the light output per unit of power input is also higher. In simple terms, COB packaging allows end users to achieve better performance with fewer temperature management requirements or lower system costs than traditional discrete component packaging.
The closer the heat energy accumulates to the part of the LED component, the greater the reliability of the LED component is affected, the deterioration of the package at high temperature (70 ° C) operation, due to the reduction of the heat dissipation interface, the maintenance of the reliability of the component is without doubt.
More streamlined optical design
The light source body with COB package design is quite similar to the point light source; The light distribution requirements required by lighting, such as the bidirectional light distribution curve of road lighting, can be achieved by optical lens design according to the point-like light source characteristics of COB light source body.
COB package meets LED lighting application expectations
From the point of view of the lighting system, the reliability of the lighting is easy to control, without too much heat dissipation design and cost; Compared with the multi-point light source assembled from discrete components, the COB package has the characteristics of a point light source, which is closer to the human needs for lighting sources. With the right system design, COB packaging technology can provide higher system light output, and it is expected that more lighting fixtures will adopt this system solution in the future.
1. Color: mainly red, green, blue, cyan, yellow, white, amber.
2. Current: Depending on the power level, the commonly used LED current varies from 20mA-2A.
3. Voltage: Voltage is related to color, generally red, green, blue VF between 1.8-2.4V; White, blue, and green voltages are between 3.0-3.6.
4. Reverse voltage Vrm: Indicates the maximum reverse voltage allowed by the LED. Above this value, the LED may be damaged by breakdown. It should be noted that some leds are not allowed to reverse (such as OSRAM), the general Vrm between 3-5V.
5. Color temperature: expressed by absolute temperature K. eg. Summer noon sun 5500K, afternoon sun 4000.
6. Luminous intensity: measured by Candela cd. This quantity indicates the convergence ability of the luminous body emitted in space, and is a common description of the optical power and convergence ability. eg. The I of the LED with diameter 5 is about 5mcd.
7. Luminous flux: measured by lumen lm. This quantity describes the size of the total amount of light emitted by the light source and is equivalent to the optical power. The existing 1W LED luminous flux can be 80-130lm.
8. Illuminance: measured by lux. That is, the luminous flux evenly distributed on the surface of 1㎡.
9. Color rendering: expressed by CRI. eg.Luxeon Cold white is 70, neutral white is 75 and warm white is 85.
10. Half value Angle: The luminous intensity is 2 times the Angle from the center line when the peak is half. According to different applications, it can be divided into high directivity, standard type and scattering type. eg.XP-C half value Angle 110°.
11. Life: Maintain to 70% of the initial luminous flux time, and this time can reach 30.000-100.000 hours.
1. Conversion of dichroic phosphor
Two-primary white LED is made of blue LED chip and YAG phosphor. The commonly used blu-ray chip is the InGaN chip, and the A1InGaN chip can also be used. The advantages of blue chip LED with YAG phosphor method are: simple structure, low cost, relatively simple production process, and YAG phosphor has been used in fluorescent lamps for many years, and the process is relatively mature. The disadvantage is that the efficiency of blue LED is not high enough, so that the efficiency of LED is low; The phosphor itself has energy loss; Phosphors and packaging materials age with time, resulting in color temperature drift and shortening of life.
2. Trichromatic phosphor conversion
Effectively improve the color rendering of LED under the premise of high efficiency. The most common way to get a tricolor white LED is to use an ultraviolet LED to excite a group of tricolor phosphors that can be radiated effectively. This type of white LED has high color rendering, light color and color temperature can be adjusted, and the use of phosphors with high conversion efficiency can improve the light efficiency of the LED. However, the method of ultraviolet LED+ trichromatic phosphor still has certain defects, such as the low efficiency of phosphor in converting ultraviolet radiation; Powder mixing is difficult; The packaging material is easy to age under ultraviolet irradiation, and its life is short.
3. Multi-chip white LED light source
The red, green and blue LED chips are packaged together, and the light they emit is mixed together to get white light. This type of white LED light source is called multi-chip white LED light source. Compared with phosphor conversion white LED, the advantage of this type of LED is to avoid the energy loss of phosphor in the light conversion process, and can obtain higher light efficiency; Moreover, the light intensity of the LED with different light colors can be separately controlled to achieve full color discoloration effect, and better color rendering can be obtained through the selection of the wavelength and intensity of the LED. The disadvantage of this method is that the semiconductor materials of LED chips with different light colors are very different, the quantum efficiency is different, the light color changes with the drive current and temperature, and the decay speed is different with time. In order to maintain the stability of the color, it is necessary to compensate and adjust the feedback circuit of the three colors of the LED, which makes the circuit too complex. In addition, heat dissipation is also the main problem plaguing multi-chip white LED light source.
LED light source is light emitting diode (LED) light source. Light-emitting diodes were invented in the 1960s, and in the following decades, their basic use was as indicators for electronic devices such as radio recorders. This kind of light bulb has the characteristics of high efficiency and long life, can be used continuously for 100,000 hours, 100 times longer than ordinary incandescent light bulbs.
1. Voltage: LED uses a low-voltage power supply, the power supply voltage is between 6-24V, depending on the product, so it is a safer power supply than using a high-voltage power supply, especially suitable for public places.
2. Efficiency: LED consumes 80% less energy than incandescent lamps with the same light efficiency.
3. Applicability: The LED is very small, each unit LED small piece is 3-5mm square, so it can be prepared into various shapes of devices, and suitable for volatile environments.
4. Stability: LED can be used for 100,000 hours, and the light decay is 50% of the initial.
5. Response time: The response time of its incandescent lamp is millisecond, and the response time of LED lamp is nanosecond.
6. Drive: LED can be driven by low-voltage direct current, with the advantages of small load and weak interference, and low requirements for the use of the environment.
7. High color rendering: LED color rendering is high, will not cause harm to people's eyes.
The COB light source means that the chip is directly packaged on the entire substrate, that is, N chips are inherited and integrated together on the substrate for packaging. It is mainly used to solve the problem of low-power chip manufacturing high-power LED lights, which can disperse the heat dissipation of the chip, improve the light efficiency, and improve the glare effect of LED lights. COB has high luminous flux density, less glare and soft light, and emits a uniform distribution of light.
COB light source is a high light efficiency integrated surface light source technology in the LED chip directly affixed to the high reflective mirror metal substrate, this technology eliminates the concept of support, no plating, no reflow, no patch process, so the process is reduced by nearly one-third, and the cost is saved by one-third.
COB light source can be simply understood as a high-power integrated surface light source, and the light area and size of the light source can be designed according to the shape structure of the product.
1, astigmatic light source, no dazzling light.
The larger the power of the particle LED light source, the more dazzling the light is, which is not suitable for children's family use, but the LED surface light source production process solves the glare problem of led lighting, and the use range is wider and safer.
2, high thermal conductivity, low light decay, long life.
The heat dissipation design of the second-generation led packaging technology is poor, and the use of a large number of radiators after the led secondary welding can not quickly export heat, resulting in the light decay of the finished led lamps. led surface light source is produced by cob process, abandoning the metal bracket packaging mode of straw hat tube and patch lamp beads, and directly mount the chip on the metal substrate with excellent thermal conductivity, the heat dissipation efficiency is dozens of times higher than that of lamp bead led light source, greatly reducing the light decay of led light source, and effectively ensuring the service life of led lamps.
3, uniform light, no color spots.
Most of the single high-power LED light sources use lenses to improve light efficiency, which increases the cost and makes the light Angle smaller; The use of multiple led lamp beads will appear uneven light and ghost phenomenon. led surface light source is the whole surface package, the advanced technology perfectly solves the problem of uneven led lamp bead light, the whole surface light, uniform light efficiency is good, is the future indoor lighting with energy-saving light source of choice.
4, stable performance, simple assembly, convenient application.
Granular led lamp beads combined into a lamp need to be welded twice and then assembled the whole lamp, high cost, more failures, virtually significantly increased the production cost of the enterprise; led surface light source overall packaging molding, to achieve the modular production of led lighting light source, users can use without secondary processing, simple to use, can be directly applied to the whole lamp production, suitable for widespread promotion.
5, luminous no stroboscopic, no ultraviolet band, green environmental protection, more in line with energy conservation and environmental protection needs.
1, soldering iron welding: soldering iron (maximum 30W) tip temperature does not exceed 300℃; Welding time does not exceed 3 seconds; Weld at least 4 mm from the colloid.
2, dip welding: the maximum temperature of immersion welding 260℃; Immersion welding time does not exceed 5 seconds; Dip weld position at least 4 mm from the colloid.
1, LED size: 0603, 0805, 1210, 5050 refers to the LED light emitting elements used on the LED belt ----LED size (imperial/metric), the following is a detailed description of these specifications:
0603: Converted to the metric system is 1005, that is, the length of the LED component is 1.0mm, the width is 0.5mm. The industry is referred to as 1005, and the British name is 0603.
0805: Converted to the metric system is 2125, that is, the length of the LED component is 2.0mm, the width is 1.25mm. The industry is short for 2125, and the British name is 0805.
1210: Converted to the metric system is 3528, that is, the length of the LED component is 3.5mm, the width is 2.8mm. The industry is known as 3528, or 1210 in English.
5050: This is the metric name, that is, the length of the LED component is 5.0mm, the width is 5.0mm. Industry abbreviation 5050.
Number of LED lights: 15 lights, 30 lights, 60 lights refers to the number of LED components welded on the LED strip per meter length, generally speaking, the 1210 specification strip is 60 LED per meter, 5050 specification strip is 30 LED per meter, and the special has 60 LED per meter. The price of LED strips with different LED quantities is different, which is also an important factor to distinguish the price of LED strips.
Luminous intensity, commonly used unit is mcd, that is, millicandra. The higher the value, the greater the luminous intensity, that is, the brighter. This is an important indicator to evaluate the brightness of the LED lamp belt, the higher the brightness requirements of the lamp belt the more expensive. This is because high-brightness LED chips are expensive, and the higher the brightness, the more difficult the package.
SMD components emit light at an Angle of 120 degrees. The greater the luminous Angle, the better the astigmatism effect, but relatively, the brightness of its luminous is correspondingly reduced. The light Angle is small, the intensity of the light is up, but the range of irradiation will be reduced. Therefore, another important indicator to evaluate the LED lamp belt is the luminous Angle. Now there are some bad manufacturers on the market, in order to improve the brightness of the light to earn higher profits, deliberately reduce the Angle of light, a little accidentally, you will buy such defective components.
The input voltage of the LED lamp belt is generally used as DC 12V, and some are 24V.
1, it is best to use "pure" DC power supply
Some suppliers produce LED products through the "resistance and capacitance reduction" method to power LED, this method will affect the life of LED products. It is best to use a switching power supply, so that not only the "ripple coefficient" of the LED power supply is reduced, but also the voltage is more stable.
2. Do a good job of electrostatic protection
When processing and production, LED should take certain anti-static methods, such as: The workbench should be in contact with the ground, the workers should wear anti-static clothing, bring anti-static rings, and anti-static gloves should also be brought, the conditions are good, you can also install anti-static ion fans, during the period to ensure that the humidity of the workshop is about 65%, so that the air is too dry to produce static electricity, and other colors LED a green and blue easy to be damaged by static electricity. And the quality of LED is related to his anti-electricity ability, and the anti-static ability of good quality LED is better.
3, temperature will affect the internal resistance of the LED
LED rated current is about 20mA, when the temperature rises, its internal resistance will become smaller. If the method of voltage regulation is used for power supply, it will cause the LED current to rise, and when the current exceeds 20mA, the life of the LED will be affected, and the LED will burn out directly if the situation is serious. Therefore, it is best to choose a constant current source power supply, which can ensure that the current of the LED will not change because of changes in temperature.
1, the production must wear anti-static gloves, anti-static wrist, soldering iron must be grounded, it is strictly prohibited to touch the white LED two lead pins. Because the anti-static of the white LED is 100V, and the static electricity of the human body will damage the crystalline layer of the light-emitting diode when the working humidity is 60%-90% on the workbench, the diode will fail (not bright) after working for a period of time (such as 10 hours), and it will fail immediately in serious cases.
2, welding temperature is 260℃, 3 seconds. Too high temperature and too long time will burn the chip. In order to better protect the LED, the LED colloid and the PC board should be maintained at a distance of more than 2mm, so that the welding heat is dispersed in the pin.
3, the normal working current of the LED is 20mA, and small fluctuations in voltage (such as 0.1V) will cause large fluctuations in current (10%-15%). Therefore, in the circuit design, different current limiting resistors should be paired according to the voltage drop of the LED to ensure that the LED is in the best working condition. If the current is too large, the LED will shorten the life, and the current is too small to reach the required light intensity.
In general, when the bulk supply will be LED spectroscopic color separation, that is, the LED light intensity, voltage, light color in the same package of products are consistent, and indicated on the spectroscopic color table.
Many people have encountered the problem of LED leakage. Some are found during production testing, and some are found when customers use them. The timing of leakage also varies. Some are tested after the LED package is completed, some appear after being placed in the warehouse for a period of time, some appear after aging for a period of time, some appear after customer welding, and some appear after customer use for a period of time.
The specific cause of the LED leakage problem has been troubling the engineers of the packaging plant. Many people believe that the reasons for LED leakage are as follows
Electrostatic damage, wafer leakage, silver glue problems, wire bias welding, electrostatic breakdown leakage during transportation, improper debugging of the packaging platform or packaging is believed to cause leakage of the finished product.
Looking at the conclusions on the Internet, most people attributed the cause of LED leakage to electrostatic damage. Their proposed solution is to emphasize anti-static measures. This makes the packaging factory and the user very difficult. Because even if they do a good job of anti-static measures, LED leakage phenomenon will still exist. So, what is the cause of LED leakage? At present, the most likely causes of LED leakage are the following (in order of likelihood) :
1. The chip is tainted (the most important and highest problem)
2. The silver glue is too high
3, line bias welding
5. Improper use
6, the chip itself leakage
7. Improper process causes chip cracking
8. Static electricity
9. Other reasons
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