1. What is SMD LED?
SMD LED (acronym for Surface-Mount-Device, Light-Emitting-Diode) is a type of LED characterized by having a 3 in 1 encapsulation, meaning that it integrates all 3 colors (Red, Green, Blue) in a single system.
SMD LEDs are rectangular in shape and consist of three cells. These cells contain a luminescent element (semiconductor crystal) that produces light when current flows through it.
To protect the SMD cells, resins are used to completely cover the upper part. These resins for SMD are available in various colors and shades.
Depending on the number of cells in the SMD led, it will have a certain number of contacts for welding. For a single-color LED, one of them is always the anode (+) and the other will be the cathode (-). In the case of an SMD RGB LED it usually has a cathode contact and an anode for each luminescent element. Depending on the manufacturer and the LED specification, the configuration and number of connection points can vary.
2. What is COB LED?
Chip on board (COB) technology is a method of directly mounting red, green, and blue chips onto a printed circuit board (PCB). Packaging the bare chips directly onto the PCB enables a much higher chip density while creating a flat uniform LED surface. The combination of three-color values allows the chips to achieve a higher color gamut and replicate true-to-life imagery.
In other words, with COB LED technology, the number of LEDs that can be placed in any given area of a display is way higher than with other LED packaging approaches, such as Surface Mounted Diode (SMD) and Dual in-line Package (DIP).
Occupying less space on the board without any bonding wires allows for a tighter pixel pitch. The tighter the pixel pitch, on the other hand, the higher resolution. This is one of the reasons behind COB’s breakthrough in the LED packaging world. The potential of improving image quality, reliability, and energy efficiency of a display is huge and will be only further explored in various future applications.
3. What is GOB LED
GOB is short for Glue-On-Board. GOB LEDs are a type of LED technology that uses transparent glue to cover the entire surface of the SMD LED display modules. GOB is an upgraded version of SMD.
Usually, since there is no way to install MASK on SMD LED displays below 2.5mm pixel pitch, in order to protect SMD LEDs with pixels below 2.5mm from falling off, COB technology is used to protect the LEDs, which can effectively prevent impact, and the front is waterproof and dust proof.
In summary: For pitches above 2.5mm, SMD LEDs are usually selected. For pitches between P1.25 and P2.5mm, GOB LEDs are selected. For pitches of P1.25mm and below, COB is recommended.