The pursuit of smaller pitch HD display COB&SMD which is the best
Today, in the application field, COB and SMD two technologies are “equal”, but in the field of micro-pitch LED, COB is becoming the mainstream technology of the industry that major manufacturers are competing to develop. So what’s the difference between COB and SMD?
COB&SMD difference
01. Stability
SMD adopts lamp bead bracket and epoxy resin. Due to the different expansion coefficient, it is easy to cause the bracket and epoxy resin encapsulation shell to fall off and have gaps during reflow welding, and the dead lamp phenomenon gradually appears in the later use, resulting in a high defect rate.
COB integrated package does not need to go through reflow lighting, avoiding the problem of gap between lamp holder and epoxy resin caused by high temperature welding in the welding machine, and the phenomenon of dead lamp is not easy to occur after the product leaves the factory. The surface uses lens package, effectively protects the LED chip, and the protection ability is enhanced.
02. Excellent heat dissipation
SMD products are mainly heat dissipation through colloids and four pads, the heat dissipation area is small, and the heat will be concentrated in the chip, which will cause serious light attenuation phenomenon for a long time, and even dead lamp phenomenon, reducing the service life and quality of the display screen.
COB integrated packaging products package the chip on the PCB board, directly through the entire PCB board area for heat dissipation, heat is easy to dissipate, extend the display life.
03. Compression and collision resistance
SMD high-density display uses solder to stick the LED lamp on the lamp board, which is a convex structure, and each lamp has only 4 small pads, which is easy to drop the lamp and die the lamp because of extrusion, touch and other reasons.
COB integrated package the LED chip is packaged on the PCB board through solid crystal, and the surface is packaged with lens, which is smooth and smooth, and more crashed-resistant.
04. Moisture, dust and electrostatic resistance
The lamp pad of the SMD display screen is bare, which is prone to short circuit between the lamp pad when it encounters water or moisture. The face mask used is uneven and difficult to clean when it gets dusty; The metal support used is easy to be oxidized; The bare lamp foot pad is easily affected by static electricity, and the phenomenon of dead lamp appears. Waterproof, moisture-proof, dustproof, anti-static, and anti-oxidation exist.
The COB integrated package display screen adopts panel packaging technology, and has the functions of moisture-proof, dust-proof, and anti-static.
05. Wide perspective
The SMD display reduces the viewing Angle due to the high packaging of the lamp cup, the accuracy error in the mounting process, and the uneven face mask.
COB small pitch display integrated package without mask protection, left and right view Angle increased to 160°. The SMD discrete device is blocked by the bracket, and the viewing Angle is only 140°.
06. Surface light source relieves granular feeling
SMD products have a small luminous outlet, a strong sense of granularity at close range, and LED light has a very strong directivity, so when the point light source is applied, it has a very harsh glare.
The COB integrated package forms a surface light source, which produces soft light, effectively alleviates the sense of granularity, and reduces the glare and stinging sensation generated when the screen is viewed for a long time.
07. Anti-moire finish
SMD adopts the form of particle packaging, and the black filling area is small, which is easy to cause moire phenomenon (water ripple during shooting).
The COB is a flat package with exclusive laser treatment on the surface to effectively reduce the generation of moors.
08. Anti-noise lens technology
SMD: Because of the large wavelength span of the selected chip, each pixel of the chip has a small noise phenomenon.
COB: Select the chip with minimal wavelength difference, and use a unique optical lens technology, so that the brightness and color differences between pixels become invisible to the naked eye, completely no picture noise, color more saturated and pure.
And the COB package is mainly to solve the problem of LED small pitch, its product line is also mostly concentrated in P1.25, like P1.25, P0.9, P0.6 and so on are almost all the COB structure. Smaller dot spacing can lead to higher resolution, resulting in higher clarity and better picture quality when displaying images.
