COB LED Assembled Circuit Board

 

COB LED, Chip On Board LED boards represent a category of high-power LED light sources. These boards possess the capacity to encapsulate multiple LED chips on a singular aluminum substrate. The configuration of the COB LED board entails the connection of multiple LED chips in parallel, with a side-by-side arrangement. The light is emitted and focused by sharing the same optical lens. COB LED boards are used in applications where high light efficiency and brightness are very important, such as outdoor lighting, automotive lighting, and backlighting. Additionally, COB LED boards find application in ultra-high definition display solutions, particularly in small micro-pitch LED displays, where they contribute to enhancing the viewing experience and safety.

How to Design a COB LED PCB?

1. Substrate Selection

Substrates are typically composed of materials that facilitate effective heat conduction and reflect light. Metal substrates are relatively cost-effective, while ceramic substrates are particularly effective in dissipating heat.

2. Packaging

Coating: It is very important to protect LED chips and solder joints with a special layer, like an organic adhesive or resin. This layer functions to shield against damage from external environmental factors.

Lens design: According to the stipulated application requirements, the integration of lenses onto the surface of the LED PCB is a viable solution to enhance light distribution and optimize the lighting effect.

3. Thermal Design

Heat dissipation structure: the dissipation of thermal energy from the COB LED board is mostly influenced by the substrate, which highlights the importance of using a high-quality substrate. Using extra heat-dissipation methods, like heat sinks and heat pipes, can make the heat dissipation even better.

Chip Arrangement: Adequate chip spacing is crucial to prevent over-dense chips from causing heat accumulation.

4. Optical Design

Color temperature and color rendering index: The particular application scenario will determine which color temperature and color rendering index is best.

Light mixing design: To achieve good light mixing efficiency in multi-color COB LED boards, it is required to design the arrangement and driving mechanism of LED chips of different hues reasonably.

5. Circuit Design

Driving circuit: The driving circuit should be designed to ensure stable operation and optimal electrical performance of the LED chips.

Intelligent control: In scenarios that demand intelligent control, the integration of an intelligent dimming system enables the adjustment of lighting brightness according to actual usage.

How to Make a COB LED Board?

1. Prepare the Substrate

To guarantee that the next operation proceeds smoothly, pick the appropriate substrate and clean it.

2. Mounting and Dispensing

To create an electrical connection between the LED chip and the substrate, apply the proper amount of conductive adhesive to the chip’s positioning point on the substrate.

Place the LED chip in the dispensing position precisely. After doing this using tweezers or a vacuum suction pen, put the substrate containing the chip into a thermal cycling oven and maintain the temperature there for a while.

3. Wire Soldering

The aluminum wire welding machine is to be utilized to electrically connect the LED chip with the electrodes on the substrate, thereby forming an internal lead wire welding. This will guarantee that the chip and substrate have a strong electrical connection.

4. Dispensing and Curing

The preparation of the fluorescent adhesive should be conducted according to the desired color temperature. Subsequently, the automatic dispensing machine should be utilized to apply the fluorescent adhesive to the chip resistors and LED patches on the substrate.

5. Inspection and Packaging

Examine the soldered substrate and fix or swap out the non-emitting LED chips. The chip resistors that aren’t working right should be fixed to make sure the LED board performs well and is high quality.

How Does the COB LED Board Work?

A COB LED board consists of multiple LED chips that are directly attached to a substrate using conductive adhesive. The substrate, typically composed of metal or ceramic, is highly conductive, facilitating efficient power and heat transfer.

The operation of a COB LED board entails the delivery of an electrical current through each LED chip embedded within the substrate’s circuitry, thereby inducing light emission. The light emanating from each chip is diffused and scattered by the enclosing material, resulting in the creation of a uniform light field.