Common types and application fields of LED lamp beads
There are many kinds of LED light sources. Different LED lights have slight differences in the lamp beads used in their internal structures. Today, I will make a comprehensive and systematic scientific introduction to the common types of LED lamp beads for your reference.
1-pin plug-in type (DIP)
This LED lamp bead is the simplest light-emitting diode in structure. Because there are two "foot" shaped filaments under the lamp bead, which can be directly connected to the circuit board, it is called a pin inserted lamp bead.
It has good security, stable performance, can emit light under low voltage, low loss, high efficiency, long life, and can also conduct multi-color dimming.
This kind of lamp beads can have various shapes, such as round, oval, square, or even irregular shapes. Although the shape and size are not very different from each other roughly, the cross section of different shapes of lamp beads is different.
If you carefully observe different lamp beads, you will find that the number of "pins" of some lamp beads is different. These "pins" can make the LED produce light of different colors.
In the field of lighting, pin inserted lamp beads are rarely used; It is generally used as lamp, indicator light, display screen, etc.
2 Small power surface mount (SMD)
This kind of lamp bead light source is to weld the LED on the surface of the circuit board, rather than through the circuit board. Its size is small, some even smaller than the pin inserted lamp beads.
There are many models of this kind of lamp beads, the most commonly used ones are 2835 (PCT), 4014, 3528, 3014, etc. The first two digits of each model number represent the width "x.x mm", and the last two digits represent the length "x.x mm". For example, 2835 represents 2.8mm wide and 3.5mm long.
The lamp bead with yellow phosphor on its surface emits white light
This kind of small power meter can be used in a wide range. Because of its small size, it can be used anywhere it is pasted, so it can be pasted in all kinds of LED lights, and the number can be adjusted and changed according to needs.
3 High power surface mount type
The third kind of lamp bead is also a surface mount type, which is similar to a small power meter in essence, except that it is a little more powerful and bulky; In terms of fine structure, a lens is added to better focus the light.
There are also many types of lamp beads attached to high-power meters:
Here is a tip: if the surface color of the lamp bead is yellow, it is generally low color temperature; If the surface color is green, it is generally high color temperature; If there is no phosphor and the lamp bead is colorless and transparent, it is generally colored.
This kind of lamp bead is usually used after being covered with a lens (to facilitate the convergence or dispersion of light), and is often made into a spotlight or projection lamp.
4 Integrated Packaging (COB)
The last type is the integrated package lamp beads, which encapsulate many lamp bead chips on the same board, and the size is the same as the diameter of a 50 cent coin.
Generally, there are round, long strip and square. The long strip integrated board is often used as a desk lamp.
Integrated packaged LED lamps are increasingly used in indoor and outdoor lighting.
There are many welding methods for LED lamp beads on the chip, and the following is one of the commonly used methods for reference. First, use an electric soldering iron to heat some soldering tin on the positive and negative electrode pads of the lamp bead (the soldering tin must not be too much, otherwise, the positive and negative electrode pads will be connected once heated with a hot-air gun), then use a hot-air gun to heat the positive and negative electrode pads at the same time, after the tin melts, use tweezers to place the positive and negative electrodes of the lamp bead on the corresponding pad.
LED is the light emitting diode, which is a semiconductor solid light emitting device that converts electric energy into light energy. Its core is the PN junction. In addition to the forward conduction, reverse cut-off and breakdown characteristics of the general PN junction, it also has the light emitting characteristics under certain conditions. Its structure mainly includes the following parts: lead, bracket, encapsulation glue, bonding wire, LED chip, solid crystal glue and phosphor. The discoloration failure of LED lamp bead is closely related to its material, structure, packaging process and service conditions. The following will analyze the causes of its discoloration through specific cases.
LED lamp beads are also called light emitting diodes. It has a wide range of applications. Its luminous colors include red light, emerald green light, yellow green light, yellow light, purple light, blue light, white light and orange light. The above is monochromatic light. It can also be made into two or three colors.
The gold wire used to package LED lamp beads contains more than 99.99% gold. It is produced by drawing gold from this material. In addition to 99.99% gold, this gold also contains less than 1% other trace elements. One of the core components of LED lamp bead packaging is gold wire, which is the bridge connecting the luminous chip and the welding point, and plays a decisive role in the service life of LED lamp bead. So how to identify the purity of gold thread?