Sunshinelux is a professional wholesale led light supplier and manufacturer in China since 2012.
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Sunshinelux is a professional wholesale led light supplier and manufacturer in China since 2012.
Ningbo Sunshinelux Lighting Co., Ltd. was founded in 2012 and is a certified and registered company. It has become one of leading suppliers of LED products and application solutions. At present, the main products are Rechargeable Work light, Solar Work Light,Work Light, Tripod Work Light, LED Scoket Worklight, Flood Light, High Bay LED Lights, Solar Flood Light and Solar Street Light and LED Street Light. With integrated R&D, manufacturing, sales and service systems. Sunshinelux is committed to providing high-quality and high-performance LED products and solutions to all customers, including professional channel customers and terminal customers. After 10 years of developing, now we have a factory about 5000 square meters. The daily production capacity is more than 10000 sets of led lights, and the daily aging test capacity is 10000 sets. In addition, our factory's own skilled workers, professional overseas sales, and strict QC personnel will help you win more and more market share. Here, we will achieve double winning.
I. Description
This article mainly lists some typical failure cases encountered by customers using APT LED light sources and APT in the long-term experimental process, and analyzes the possible failure cases.
Finally, the corresponding preventive measures are given to guide customers to better use the APTLED light source.
2. LED failure type and failure mechanism (mode)
1) LED failure types can be divided into:
A catastrophic failure is a failure that can cause the LED to fail to emit light or to emit only weak light under normal galvanic current.
Parametric failures are failures that cause critical characteristics to deviate from acceptable ranges.
2) LED failure mechanism (mode) can be divided into:
A Encapsulation failure: refers to the failure caused by the corrosion of the bracket, the fracture of the connecting line, the structural change (degradation) of the packaging material (die glue, packaging glue, etc.), and the failure of the phosphor powder.
B Chip failure: refers to the failure caused by chip material defect, electrode material deterioration, PN junction structure damage, poor ohmic contact of chip electrodes and chip pollution.
C Electrical stress failure: refers to the failure caused by overcurrent and overvoltage shock, overdrive, electrostatic damage, etc.
D thermal stress failure: refers to the failure caused by excessive junction temperature, harsh environment, etc.
E Assembly failure: refers to the failure caused by poor welding, improper assembly, etc.
3. Typical failure cases and prevention of LED applications
failure phenomenon
failure type
Possible reasons for failure
Case illustration
failure mechanism
Precaution
1. Dead light (no
Bright)
catastrophic loss
A/D
B/C
A/C
Poor heat dissipation of LEDs, aging of solid products, delamination of layers, and chip detachment
Overcurrent shock, gold wire burns
Over-current and over-voltage shock/movement, chip burnout (open circuit or short circuit)
Do a good job of LED heat dissipation to ensure that the LED heat dissipation channel is smooth (prevent the LED from floating and tilting during soldering)
Do a good job of EOS protection to prevent overcurrent and overvoltage shocks or long-term LED movement
Prevent overcurrent and overvoltage from striking the LED
During use, not done
4 ESD protection, lead to LED
PN junction is broken down by electrostatic
B/C
Do a good job of ESD protection
Improper use by the user, such as the soldering temperature is too high, the colloid expands violently, and the gold wire is broken, or the external force impacts the packaging colloid, and the gold wire is torn off.
Solder according to recommended soldering conditions; take care to protect package structure from damage during assembly
Cracked
The LED is wet and not dehumidified,
Glue cracks and gold during flow soldering
line break
The setting of the reflow soldering temperature curve is unreasonable, resulting in the severe expansion of the colloid during the reflow process and the breakage of the gold wire
The Zener is broken down to cause a short circuit, or the positive and negative poles of the LED are short-circuited or the PCB board is short-circuited during assembly.
The overcurrent causes accelerated deterioration of the chip electrodes, poor contact 1, and a serious increase in Vf (it can be increased by about 3V)
to above 5V)
A/D
Dehumidify according to the conditions and then reflow soldering according to the recommended reflow parameters
2. Optical transmission
faint (micro
Bright)
catastrophic loss
effect
The structure of PN junction is seriously damaged after overvoltage or overcurrent shock 2, and Vf rises seriously
(can be raised by about 3V
to above 5V)
A/D
B/C/E
B/C
B/C
Over-reflow soldering per recommended reflow parameters
Do a good job in ESD protection; avoid short-circuiting between positive and negative electrodes; check whether the PCB circuit is short-circuited
Use within rated current
led
use within rated voltage and current
with LED
Severe ESD damage, PN junction structure is seriously damaged, VF is strictly increased (from about 3V to more than 5V)
B/C
Do a good job in ESD protection;
3. Great light decay
(>10%)
parameter invalidation
4. Color temperature/color coordinate drift
parameter invalidation
Poor heat dissipation or overcurrent use causes heat accumulation, and the structure of the encapsulation colloid changes (blackens, hardens, or even cracks) under high temperature conditions
Under harsh environmental conditions such as high temperature, high humidity or acidity, the phosphor powder will deteriorate and decompose, and its performance will decrease.
Overcurrent use, add
3-speed chip aging, chip
Light efficiency drops
ESD damage, Ir rises seriously or other circuit channels are turned on to divert a part of the current
The sulfur (S2-) element in the environment penetrates into the interior of the LED bracket. Under certain temperature and humidity conditions (the heat promotes the intensification of molecular motion), the -2-valent sulfur and +1-valent silver (the bracket silver coating) occur Chemical reaction to generate black Ag2S (LED vulcanization phenomenon)
Poor heat dissipation or overcurrent use causes the most heat to accumulate,
I The structure of the encapsulating colloid changes (blackening, hardening, or even cracking) under high temperature conditions
The sulfur (S2-) element in the environment penetrates into the interior of the LED bracket. Under certain temperature and humidity conditions (the heat promotes molecular motion to intensify), the -2-valent sulfur and +1-valent silver chemically react to form black Ag2S (LED). vulcanization phenomenon)
B/C
B/C
A/D
Replace the encapsulant with better heat resistance; ensure sufficient heat dissipation and use within the rated current (overcurrent use may be unintentional, such as parallel use of LEDs with mismatched voltages, resulting in uneven current distribution in different branches, which also It will cause a large difference in the degree of brightness and darkness between different branches)
Choose phosphor materials with high reliability; avoid using in high temperature and high humidity environment for a long time; avoid using in acidic environment
Use within rated current
led
Do a good job in ESD protection;
Choose the best quality PCB board, solder and other supporting materials (such as rubber products, sulfur soaps contain sulfur, you must pay attention to precautions), avoid contact with sulfur-containing substances; avoid storing in the same space environment with sulfur-containing and oxidizing substances, If TOP LED white light products are not sealed, avoid lighting in acidic environment
Replace the encapsulant with better heat resistance; ensure sufficient heat dissipation and use within the rated current (overcurrent use may be unintentional, such as parallel use of LEDs with mismatched voltages, resulting in uneven current distribution in different branches, which also It will cause a large difference in the degree of brightness and darkness between different branches)
Use quality-assured PCB sheets, solders and other supporting materials (such as rubber products and sulfur soaps that contain sulfur, and precautions must be taken), avoid contact with sulfur-containing substances; avoid storing them in the same space environment as sulfur-containing and oxidizing substances, TOP If LED white light products are not sealed, avoid lighting in an acidic environment.
5. Blink (non-
Human control
system)
parameter invalidation
No heat dissipation, LED temperature increases, phosphor excitation efficiency decreases, and the chip wavelength red shifts
Under harsh environmental conditions such as high temperature, high humidity or acidity, the phosphor powder will deteriorate and decompose, and its performance will decrease.
The colloid is affected by external force, the gold ball and the two solder joints are not completely peeled off, and sometimes they are peeled off with thermal expansion and contraction
(open circuit), or the gold wire collapses and is in a critical short circuit state
A/D/E
Do a good job of LED heat dissipation to ensure that the heat dissipation channel of the iiE LED is smooth (prevent it during soldering).
LED suspension, tilt)
A/D
Choose high-reliability phosphor materials; avoid long-term use in high temperature and humidity environments; avoid using in acidic environments
Avoid strong external force on the colloid; the size of the nozzle of the SMT equipment should be selected according to this; strictly control the LED process to prevent the LED gold wire from collapsing
Drive power failure, resulting in intermittent drive current
4. Summary
1) Summarizing the past experience, in the failure cases of LEDs, most of the failure cases are due to the problem of the gold wire connection. The advantages of high reliability can reduce poor heat dissipation and overcome all failure risks caused by gold wires°
2) We know that LED is a constant current drive device. Long-term use of constant voltage drive will greatly affect the life of the LED. Overvoltage and overcurrent impact and use may also cause the failure of the LED. It should be used within the rated current of the LED.
3) LEDs are temperature-sensitive devices. The increase in junction temperature will affect the reliability (lifetime), electrical parameters (forward voltage, maximum injection current, light efficiency), chromaticity (color coordinates, color temperature) of the LEDs. Care should be taken to ensure that the LEDs Smooth cooling channels.
4) LEDs are also electrostatic sensitive devices, and ESD protection should be done during use to prevent LEDs from being damaged.
Ningbo Sunshinelux Lighting Co., Ltd. is a manufacturer specializing in the production of 50w led light，led ufo lights，led work lamp，rechargeable magnetic work light，best solar flood lights，solar road light，50 watt led street light.
Sunshinelux as a professional led light supplier, we are the top led floodlight manufacturer, china led work light, led warehouse lighting suppliers, china solar lamp, street light factory, please believe that we will provide the best quality, best service, best price, please contact us.
