What are COB led boards? COB LED Strip

Table of Contents

What are COB led boards? COB led boards are an LED light source that uses Chip On Board technology. It directly encapsulates multiple LED chips on the same substrate and then connects them to the circuit board through a special connection technology. Compared with traditional LED light sources, COB led boards share a heat dissipation substrate for multiple LED chips, which can dissipate heat more effectively and improve heat dissipation efficiency.

What are COB led boards?

COB led boards, full name Chip On Board, is a high-power LED light source that directly encapsulates multiple LED chips on an aluminum substrate.

COB led boards connect multiple LED chips in parallel, place them side by side on the same substrate, and emit and focus light by sharing the same optical lens.

COB led boards are mainly used in fields with high requirements for light efficiency and brightness, such as outdoor lighting, automotive lighting, backlighting, etc. In addition, COB led boards are also used in ultra-high-definition display solutions, especially in small micro-pitch LED display screens, which can effectively improve viewing experience and safety.

How to design COB led boards?

Designing COB (Chip On Board) led boards requires the following key steps and technical points to be considered:

1. Substrate selection

Material selection: Substrates are usually made of materials with high thermal conductivity and high reflectivity. Metal substrates are relatively low in cost, while ceramic substrates have better heat dissipation performance.

2. Packaging

Coating protective layer: Apply a layer of organic glue or resin on the LED chip and leads to protect the chip and solder joints and prevent damage to them from the external environment.

Lens design: According to application requirements, lenses can be added to the surface of the led boards to optimize light distribution and improve lighting effects.

3. Heat dissipation design

Heat dissipation structure: The heat dissipation of COB led boards mainly depends on the substrate, so the heat dissipation performance of the substrate is very important. Auxiliary heat dissipation measures such as heat sinks and heat pipes can also be used to further improve the heat dissipation efficiency.

Chip arrangement: Reasonably design the chip arrangement spacing to avoid heat accumulation caused by too dense chips.

4. Optical design

Color temperature and color rendering index: Select the appropriate color temperature and color rendering index according to the application scenario.

Mixed light design: For COB LED boards with multiple primary colors, it is necessary to reasonably design the arrangement and driving mode of LED chips of different colors to achieve a good mixed light effect.

5. Circuit design

Drive circuit: Design a suitable drive circuit to ensure the stable operation and good electrical performance of the LED chip.

Intelligent control: For application scenarios that require intelligent control, an intelligent dimming system can be integrated to adjust the lighting brightness according to actual usage.

How to make COB led boards?

The production of COB led boards can be summarized into the following steps:

1. Prepare the substrate

Select the appropriate substrate material and clean it to ensure the smooth progress of the subsequent process.

2. Glue dispensing and mounting

Apply an appropriate amount of conductive glue on the LED chip placement point on the substrate to achieve electrical connection between the chip and the substrate.

Place the LED chip accurately on the glue dispensing position. You can use a vacuum suction pen or tweezers to operate it, and then put the substrate with the chip attached into a thermal cycle oven and keep it at a constant temperature for a period of time. Take it out after the conductive glue is cured.

3. Wire welding

Use an aluminum wire welding machine to electrically connect the LED chip to the electrode on the substrate to form an inner lead welding to ensure a good electrical connection between the chip and the substrate.

4. Glue dispensing and curing

Prepare fluorescent glue according to the required color temperature, and then use an automatic glue dispensing machine to cover the fluorescent glue on the chip resistor and LED chip on the substrate.

Put the substrate with fluorescent glue applied in the oven for baking to completely cure the fluorescent glue to achieve the required color temperature and light effect.

5. Detection and packaging

Inspect the soldered substrate, repair or replace the LED chips that do not emit light, and repair or replace the chip resistors that do not work properly to ensure the performance and quality of the led boards.

Apply a layer of organic glue or resin on the LED chips and leads to protect the chips and solder joints and prevent them from being damaged by the external environment.

How do COB led boards work?

The working principle of COB led boards is mainly based on its packaging structure and electrical connection method:

Electrical connection: COB led boards are composed of multiple LED chips, which are directly adhered to the substrate through conductive glue. The substrate is usually made of metal or ceramic with good electrical and thermal conductivity.

Light-emitting process: When the power supply is connected to the COB led boards, the current flows through each LED chip through the circuit on the substrate, making the chip emit light. The light emitted by each chip is reflected and scattered by the packaging material to form a uniform light field.

Heat dissipation mechanism: A significant advantage of COB led boards is its excellent heat dissipation performance. Since the LED chip is directly attached to the substrate, the heat can be quickly conducted to the external environment through the substrate, which effectively reduces the temperature of the chip and prolongs its service life.

What is the lifespan of a COB led?

The lifespan of a COB led board is usually between 50,000 and 100,000 hours. This lifespan range means that under normal working conditions, COB led boards can last for many years. The long lifespan of COB led boards is mainly due to its good heat dissipation performance and compact packaging structure.

What are the advantages of COB led boards?

COB led boards have the following advantages:

1. Optical performance

High brightness and uniformity: COB led boards can provide higher brightness output by integrating multiple LED chips. Its light emission is uniform and soft, without ghosting and light spots, and can achieve a more uniform light field.

Wide viewing angle: COB packaging adopts shallow well spherical light emission, which has a better optical diffuse color effect.

High color rendering: COB light source has a high color rendering index and good color rendering, which can provide more natural and accurate light.

2. Heat dissipation performance

Excellent heat dissipation capacity: Multiple LED chips of COB led boards share a heat dissipation substrate, which quickly conducts heat to the external environment through the substrate, thereby effectively reducing the chip temperature and extending the service life.

3. Cost-effectiveness

Low cost: Compared with traditional SMD packaging, COB light source modules can save device packaging costs in lighting applications.

High manufacturing efficiency: The COB packaging process is simplified, eliminating the process of patch and reflow soldering, and the production efficiency is higher.

4. Structure and application

Light and thin: COB led boards have a simple structure and can use PCB boards of different thicknesses according to customer needs, reducing the weight to about 1/3 of traditional products, which is convenient for transportation and installation.

Anti-collision and pressure resistance: COB packaging encapsulates the LED chip in the concave lamp position of the PCB board, and then encapsulates and cures it with epoxy resin glue. The surface of the lamp point is convex into a spherical surface, which is smooth and hard, resistant to collision and wear.

Bendable: COB packaging has the ability to bend, and the bending of the PCB will not damage the packaged LED chip, so various special-shaped screens can be easily made.

Easy to maintain: COB light source has a simple structure and is easy to maintain. You only need to clean the optical lens to maintain brightness.

What are the disadvantages of COB led boards?

Although COB led boards have many advantages, they also have some disadvantages:

Heat dissipation problem: Due to the dense arrangement of chips, the heat dissipation area is limited, which easily leads to heat accumulation, affecting the light efficiency and life.

Relatively low light efficiency: Part of the light is absorbed after reflection between chips, resulting in a light efficiency that is about 10% lower than that of SMD packaging.

Difficult to repair: The chip and substrate are packaged as one, and a single chip needs to be replaced if it is damaged, and the repair cost is high.

High initial cost: High requirements for materials and processes, resulting in relatively high initial costs and prices.

Limited color selection: Mainly monochrome, the color selection is not as rich as SMD LED.

In summary, as an innovative chip-on-board packaging technology, COB led boards, with its unique principle, have shown significant advantages in light uniformity, heat dissipation, reliability and other aspects, and are widely used in indoor and outdoor lighting and display fields. BEST Technology has advanced COB packaging technology, efficient heat dissipation design, strict quality management system and flexible customization services. Please feel free to communicate with us at sales@bestpcbs.com for the production of COB led boards.