Behind the high-power integrated light source dead light

The integrated LED light source is to integrate several LED chips in the same bracket, and realize a high-power LED package form through internal connection. The volume is large, and the power is generally above 10W, which is usually referred to as CHIP on Board package. Form, with the popularity of LED lighting, the advantages of integrated LED light source in lighting applications are gradually recognized by the industry, and gradually become the trend of lighting applications.

Superconducting aluminum integrated light source advantages :

1. High reflectivity, which can improve the light extraction efficiency of the chip and reduce the light loss.

2. High thermal conductivity can improve the working efficiency of semiconductor chips and prolong their service life.

3. Excellent resistance to cold and heat cycle.

4. Strong anti-peeling strength and strong current conduction ability.

5. It has low thermal resistance and good stability under high temperature environment.

6. High insulation strength to ensure personal safety and equipment protection.

7. The material is tested by SGS, safe, non-toxic and harmless.

Copper plate integrated light source advantages:

Copper substrate performance

1. The bump and recessed copper substrate technology enables the LED heating area to directly contact the copper-based heat-dissipating substrate to make the thermal conductivity of the copper material 400w/mk truly exert its performance. The structure is also suitable for the chip to be directly packaged on the copper-based boss recessed table, and then the COB light source package.

2. The thermoelectric separation design is used to improve the pressure resistance of the traditional copper bracket, and the cost is much lower than that of the alumina substrate.

3. The bump-resistant copper substrate can withstand breakdown voltage of 2500kv or more and a thermal expansion coefficient of 16.9mm/mk.

Advantages of copper substrates

1. Strong mechanical stress, stable shape, high strength, high thermal conductivity, high insulation and strong bonding.

2. Excellent thermal cycle performance and high reliability.

3. Remove the thermal PAD insulation layer, reduce the thermal resistance, reduce the voids, and improve the heat conduction effect, thereby greatly increasing the power density.

4. Improve the reliability of the system and device, and the carrying capacity is large.

Reasons and analysis of integrated light source dead light

After the LED integrated light source and its application, the LED finished product customer use side for a period of time, it is possible to encounter the situation that the light source is not bright (dead light). After analyzing the light source product, the cause of the dead light can be divided into the following Kind:

First, static electricity damage to the LED chip :

Analysis of adverse causes: electrostatic damage (human body, environment and equipment) during storage, packaging and soldering of LED integrated light source.

Improvement points: ESD protection includes storage/working environment, instrument/equipment grounding, and human body static protection.

Second, the LED integrated light source is abnormally matched with the power supply or the output of the driving power supply is out of control , resulting in damage to the internal chip and gold wire of the LED integrated light source . This undesirable phenomenon is: the chip and the gold wire are obviously blackened, and the gold wire is carbonized or the chip is found by microscope observation. Burnt black.

Analysis of the cause of the failure: The output of the drive power supply is abnormal (including factors such as parameter mismatch, poor power supply performance, etc.).

Improvement point: the technicians can evaluate the electrical performance of the LED light source and the driver, the feasibility of structural safety, and the reliability improvement of the driving power supply.

Third, the LED integrated light source surface damage or cracking causes the light source to be unable to illuminate and die.

Analysis of the cause of the failure: the LED light source reaches the end of the limit, causing the colloid to fail harden or the light source is wet, causing the welding or the process of use. During the thermal expansion and contraction of the colloid, the gold wire is broken and the dead lamp is caused; in addition, the colloid is damaged during use. In the case where stress is applied to the surface of the colloid, causing the internal gold wire to break and the dead lamp (one of the B/C/D points shown in the figure to be broken) occurs, other substances adhered to the surface of the colloid during the welding process. When the gel is used for a long time, it will eventually lead to a dead light.

Improvement point: The feasibility test of the package glue parameters of the package manufacturer; according to the use temperature limit provided by the package manufacturer, the LED application manufacturer evaluates the feasibility of the heat dissipation structure; during the use and handling process, the surface of the gel is protected from damage.

Fourth, the LED integrated light source is blackened inside and causes a dead light.

Analysis of adverse causes: There are chemical substances (sulfur, halogen, etc.) that cause vulcanization in the environment of the packaging workshop; the application of structural components, glue, and sulfur in the environment of LEDs, and the presence of sulfur and halogen components in the environment, especially in high-temperature processes such as welding, accelerates the volatilization of such substances. Affecting the LED integrated light source causes the internal bracket to be vulcanized. The vulcanized bracket will affect the heat dissipation and light parameters of the product. The final result is that the LED dead light does not illuminate.

Improvement point: Whether the packaging factory or the application factory should strictly control the chemical composition of the materials, and prevent the use of sulfur-containing auxiliary materials (glue, washing water, packaging bags, gloves, etc.) and the control of sulfur in the environment, and the packaging factory must The LED integrated light source is tested for vulcanization resistance.

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