What are the differences between COB and SMD LED Chips?

What is COB(Chip On Board)?

Feature of COB LED Chips

1. Electrical stability, scientific and reasonable circuit design, optical design, and heat dissipation design.
2. The use of heat sink technology ensures that the LED has an industry-leading heat lumen maintenance rate (95%). The lifetime longer than 50000Hrs.
3. It is convenient for the secondary optical matching of the product and improves the lighting quality.
4. High color rendering, generally COB Chips RA more than 90. Uniform luminescence, no spot, healthy and environmentally friendly.
5. Simple installation, convenient use, reducing the difficulty of lamp design, saving lamp production processing and subsequent maintenance costs.

Some of our COB LED Lights

• COB LED Downlight CREE CRI90
• COB Chip LED Flood Light
• COB LED Street Light
• SMD&COD Chip LED Flood Light

What is SMD(Surface Mounted Devices)?

Model/Types	SMD LED 3030	SMD LED 2835	SMD LED 5050
Size	3.0*3.0*0.52mm	2.8×3.5×0.8mm	5.0*5.0*1.6mm
Wattage	1Watt/pcs	0.2Watt/pcs is original. But now, 0.5Watt and 1Watt/pcs are more	0.2Watt/pcs is original type, but now, mostly 3Watt-5Watt/pcs
Voltage & Current	6.2V 150mA as standard, but 3.2V 300mA available	3.2V output voltage,60mA for 0.2W; 150mA for 0.5W, 300mA for 1Watt.	3.2V 60mA for 0.2W;
Lumens	Average 110-160lm/pcs, 200lm/pcs Max	24-36lm/pcs for 0.2W type; 55-70lm/pcs for 0.5W type; 110-140lm/pcs for 1W type.	24-28lm/pcs for 0.2Watt. 200lm/watt for 3-5Watt type.
Famous brand(manufacturers)	LUMINUS(Philips), Osram, Bridgelux	Osram, EPISTAR, Bridgelux	CREE, Bridgelux, PHILIPS
Applications	Street lighting, Flood lights, High- bay lights	0.2Watt type mainly for T8 LED Tube, bulb; 0.5Watt chips mainly for LED Panel lights, led downlights; 1Watt chip mainly for LED Flood lights, high bay lights, street lights etc.	0.2W 5050 Chips mainly for DC12V 24V low voltage led flexible strip light. The 3Watt-5watt SMD5050 mainly for stadium floodlight, high power street lights

Some of our SMD LED Lights

• SMD LED Batten Light
• SMD Downlighter Recessed
• SMD3030 LED Street Light
• SMD&COD Chip LED Flood Light

What is the difference between COB and SMD chip?

1. The production process is different.

• SMD: The LED chip is fixed on the pad of the lamp bead holder with conductive glue and insulating glue, and then welded with the same conduction performance as the COB package. After the performance test, it is encapsulated with epoxy resin, and then the light is split, Cutting and taping, transport to the screen factory and other processes.
• COB: The LED chip is directly fixed on the soldering pad of the lamp bead on the PCB board with conductive glue and insulating glue, and then the conduction performance of the LED chip is welded. After the test is completed, it is encapsulated with epoxy resin.

2. The luminous effect is different

• SMD: The light-emitting surface of the SMD LED chip is scattered and there is glare
• COB: The viewing angle of COB is large and easy to adjust, and there is no glare.

Generally, The Led lights with COB chips have uniform and round spots, no astigmatism, no black spots, and no shadows; while Led luminaires with SMD chips have bright spots in the middle of the spot, halos on the outer edges, and uneven light spot transitions. You can refer to this difference about COB LED Downlight and SMD LED Downlight.

3. Packaging method: Single-point light-emitting Vs Multi-point light-emitting.

• SMD: SMD packaging uses surface mount technology to attach multiple discrete LED lamp beads to a PCB board to form a light source component for LED applications. It is a multi-point light source form.
• COB: COB packaging is a high-efficiency integrated light source technology. N chips are integrated on the inner substrate for packaging, and low-power chips are used to manufacture high-power LED chips to form a uniform small light-emitting surface.

4. Different heat dissipation effect

The small chips of COB light source are densely arranged to generate large and concentrated heat. The packaging material absorbs the heat and superimposes the heat inside the lamp body. However, it has a low thermal resistance heat dissipation method of “chip-solid glue-aluminum”, and heat dissipation is guaranteed. The SMD light source is limited by the package, and the heat dissipation needs to go through the steps of “chip-bonding glue-solder-solder-copper foil-insulating layer-aluminum”, and the thermal resistance is slightly larger;

But in the production of high-power lamps. SMD lamp beads are often arranged and dispersed, and the heat dissipation area is large, and the heat is easy to conduct. The temperature of the whole lamp is also acceptable in the long-term use. Therefore, for the temperature of the entire lamp, the general SMD solution is better than the COB solution

5. Different application areas

COB light sources are generally used in indoor lamps such as downlighter and spotlights, and the power is basically less than 50Watt. And SMD led chips can be used in almost all indoor and outdoor lamps, which can be composed of different numbers of SMD led chips with different powers, even more than 2000Watt.

6. Different color rendering index (CRI)

The color rendering index of most SMD led chips on the market is generally 70-80, and some brands have CRI90 options, such as Osram SMD2835. Most of the COB chips are above CRI90, even up to CRI97. This is also a good color rendering index. This is the reason why indoor commercial lighting with higher index requirements often choose COB led lamps.

Package Type	COB	SMD
Productivity	The efficiency of die bonding and wire bonding is equivalent to that of traditional SMD, and the efficiency of subsequent dispensing, separation, spectroscopy, and packaging is higher than that of traditional SMD.	Production efficiency is lower than COB packaging
Thermal resistance	Chip-die glue-aluminum material (low thermal resistance)	Chip-die glue-solder joints-solder paste-copper foil-insulation layer -aluminum material (thermal resistance is higher than COB package)
Lighting effect	Large viewing angle and easy adjustment to reduce light refraction loss	There is spot light and glare in the combination
Application	No mounting and reflow soldering processes are required, COB light sources are directly applied to lamps	The smd needs to be patched first and then fixed on the PCB board through reflow soldering.
Cost	low cost	Increase the cost of brackets and solder paste, increase the cost of bits and reflow soldering process