Many people hope that LED lights can be made as light as tungsten incandescent lamps, 360? full light. This is still difficult to achieve in the current LED lighting fixtures where the low voltage LED lamp bead is the light source. Reforming the shape of LED lamp beads and carrying out innovative design is the way to hope.
Figure 1 Cooling of the LED lamp bead
LED light source packaging technology innovation
Innovative design of LED light source packaging technology is the key to the new generation of LED lighting. Most of the current LED lamps use low-voltage LED lamp beads (LVLED) with low operating voltage (VF=3.2V) and high current (IF=200-700mA). When the LED lamp bead works, only 30% of the electric energy is converted into light energy, and 70% of the electric energy is converted into thermal energy. Therefore, if the heat dissipation of the LED lamp is not well done, a large amount of heat is accumulated so that the lamp cavity is always in a high temperature environment, and the constant current power source is switched. The electrolyte in the electrolytic capacitor is depleted due to high temperature, resulting in failure; the LED lamp beads are prematurely degraded due to long-term exposure to high temperatures.
The birth of HVLED (high-voltage LED) lamp bead technology brings new vitality, new ideas and new design ideas to indoor LED lighting. This will give birth to a lot of whimsical LED lighting new products and new lamps. The biggest feature of HVLED is high voltage (VF=50-280VDC) and small current (IF=20-60mA). Compared with the same power LVLED panel, its heat is much lower. HVLED is a module that connects N low-voltage LED dies in series with high voltage during packaging, and its application is also very convenient.
The package of LED dies ranges from single-core packages to N-die packages, such as COB , COF, etc., and from a series of low-voltage LED modules to a multi-string, multi-core package HVLED module. The packaging technology of LED light sources is constantly innovating.
From the perspective of application technology, COB's LED light source board, its central LED die still has difficulty in heat conduction and poor heat dissipation. LED heat will gather in the center of COB. Therefore, this LED lamp has been used for a long time. The LED dies first undergo light decay. Multi-core packaged HVLEDs can use N-uniform technology on the same power panel. The heat of each HVLED is quickly transmitted by the aluminum substrate . The HVLED works at a small current, and its heat is much lower. The heat dissipation status of the two LED lamp beads is as described in FIG.
Figure 2 ELC die LED filament column
Technologically innovative LED filament package technology
The technologically innovative LED filament package technology was developed based on the concept of HVLED. N low-power LED dies are packaged in series on a glass substrate, making it a new package different from the previous one. Taiwan Jingyuan first proposed a new concept of LED filaments. The LED cores of N ELCs were packaged on the substrate of glass columns, and they were connected in series with gold wires to form high-voltage HVLED modules, spacer mirrors, and coated with yellow phosphors. wrap. Figure 2 shows the structure of an LED filament post of an ELC die.
The innovative design of Continental LED engineers is to package N low-power LED dies directly on a glass column substrate. For example, 28 0.02W 1016 LED dies are packaged on a glass column substrate with a length of 38mm and a diameter of 1.5-1.6mm, and are connected in series by gold wires. The LED filament column has a VF=3.2X28=89.6V and an IF=10 mA. The biggest feature of LED filament column is 360 degree full-angle illumination, which is driven by high voltage (75-90VDC) and low current (10-15mA). High-quality LED die can produce high brightness (75-95lm). High luminous efficiency (120-130lm/W), high color rendering index (90-95Ra), high reliability LED filament column; different color temperature can be produced by mixing blue and red LED dies in different proportions (2870-6020K) ) LED filament column. The structure of the high-voltage LED filament column is shown in Figure 3. The blue + red dies of the LED are packaged on the glass column substrate, arranged according to a preset rule, and the lead electrodes are arranged at both ends. After the gold wires are connected in series, the yellow or yellow green is sprayed. The phosphor is wrapped all over. Pay attention to high voltage protection during the power-on test. This kind of LED filament column is working in a small current and low power state of 10-15 mA. The whole LED filament column is in a suspended contact with the whole air, the heat dissipation is smooth, the heat is very low, and it is basically not hot.
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