First, the light emitting principle of LED lamp beads:
The terminal voltage of the PN junction forms a certain potential barrier. When the forward bias voltage is applied, the potential barrier decreases, and the majority carriers in the P and N regions diffuse to each other. Since the electron mobility is much larger than the hole mobility, a large number of electrons will diffuse into the P region, constituting the injection of minority carriers in the P region. These electrons recombine with holes in the valence band, and the energy obtained during recombination is released in the form of light energy. This is how the PN junction emits light.
2. There are three types of LED lamp beads:
1. Inline low power specifications include: straw hat / helmet, round head, concave, oval, square (2 * 3 * 4) bullet, flat head, (3/5 / flat head / bread type) piranha, etc.
2. SMD patches are generally divided into (3020/3528/5050 these are front-emitting) / 1016/1024 etc. These are side-emitting light sources.
3. High-power LEDs cannot be classified into the SMD series. Their power and current use are different, and the photoelectric parameters are very different. If a single high-power LED light source is not equipped with a cooling base (usually a hexagonal aluminum base), its appearance is not much different from that of ordinary patches. The high-power LED light source is round, and the packaging method is basically the same as that of SMD patches. However, it is essentially different from SMD patches in terms of use conditions / environments / effects.
What are the models of LED chip beads?
3014 belongs to low power, each 0.1W, the use current is 30MA, because the bottom is used for heat dissipation, it is larger than the conventional low power current
2835 belongs to low power, each has 0.1W and 0.2W, and the current is 30MA and 60MA. Because the bottom heat dissipation is used, the heat dissipation area is larger than 3014, so the current can also be larger. Of course, the chip size must also be considered. , Also someone made 0.3W and 0.5W
3528 is a conventional low power, each 0.06W, the use current is less than 20MA
5050 belongs to the conventional low power, each 0.06 * 3W, the use current is within 20 * 3MA, there are three chips inside, so the current is three times that of the conventional
5730 (5630) belongs to Samsung's high-power structure, each 0.5W, the use current is 100-150MA
3030 belongs to Cree's high-power structure, each 1W, using current of 300-350MA, this structure also has 3W lamp beads (actually 2W, current 600MA)