COB packaging technology is a technology that directly packages light-emitting chips on PCB (printed circuit board) boards, and is widely used in the manufacturing of LED displays.
COB small-pitch full-color display has the advantages of high pixel density, bright colors, and high contrast, and is widely used in commercial advertising, conference displays, stage performances and other fields.
The following are the main steps of the COB small-pitch full-color display packaging method:
Preparation
PCB board preparation
Choose a suitable PCB board and ensure that its size, material, conductive properties, etc. meet the design requirements. Clean the PCB board to remove surface stains and oxide layers to improve packaging quality.
LED chip preparation
Select the appropriate LED chip according to the design requirements and ensure that the chip model, brightness, color and other parameters meet the requirements of the display screen. Sort and test LED chips to eliminate defective products.
Die attach
Adhesive Backing
Use a glue dispensing machine to place an appropriate amount of silver paste (or other conductive glue) on the printed circuit board of the PCB board. The role of silver paste is to serve as a conductive connection between the LED chip and the PCB board.
Spiny Crystal
Paste the prepared LED chip accurately onto the printed circuit board of the PCB board with a crystal pen (or crystal machine). This step needs to be performed under a microscope to ensure that the position and angle of the LED chip are accurate.
Curing treatment
Leave at constant temperature
Put the PCB board with the LED chip pasted on it into a thermal cycle oven and let it stand at a constant temperature. The purpose of this step is to solidify the silver paste to fix the position of the LED chip on the PCB board. Be careful not to leave it for a long time to prevent the LED chip coating from being yellowed or oxidized, which will affect the packaging quality.
line connection
- Bonding (wiring): Use a bonding machine (or wire bonding machine) to connect the pins of the LED chip to the printed circuit on the PCB board. This step requires precise control of the parameters of the bonding machine to ensure a firm and reliable connection.
Testing and packaging
- Test: Conduct electrical performance test on the LED chips that have been bonded to ensure that each LED chip can work normally. If there are any defective products, they need to be replaced or repaired in time.
- Packaging: According to the design requirements, the LED chip is packaged. LED chips are usually packaged with vinyl or other packaging materials to protect them from the external environment. During the packaging process, it is necessary to ensure that the packaging material is evenly coated on the surface of the LED chip and that the thickness of the packaging layer is moderate.
Appearance processing and warehousing
- Appearance treatment: Perform appearance treatment on the packaged LED display, including cleaning, polishing, spraying and other steps. Make sure the display surface is flat, smooth and flawless.
- Warehousing: Put the processed LED displays into the warehouse for management, and record relevant information such as production date, model, specifications, etc. for subsequent use and maintenance.
The above are the main steps of the COB small-pitch full-color display packaging method. In actual operation, adjustments and optimizations need to be made according to specific product requirements and process conditions.
For more detailed introduction and explanation, it is recommended to consult relevant technical documents and information.
COB small-pitch full-color display FAQs
What are the main steps in COB small-pitch full-color display packaging?
The main steps of COB small-pitch full-color display packaging include:
- Preparation Stage: Select a suitable PCB board and LED chip, and clean the PCB board.
- Chip pasting: Use a glue dispensing machine to apply conductive glue on the PCB board, and then accurately paste the LED chip onto the PCB board.
- Line connection: Connect the pins of the LED chip to the lines on the PCB board by welding or other methods.
- Curing treatment: Put the pasted and welded PCB board into the oven for curing treatment to solidify the conductive glue and fix the LED chip.
- Testing and quality inspection: Test the packaged display screen, including inspection of brightness, color, uniformity, etc. to ensure product quality.
How to ensure the accuracy and position accuracy of LED chips during the COB packaging process?
In the COB packaging process, it is crucial to ensure the accuracy and position accuracy of the LED chip. This is usually achieved by:
- Use high-precision equipment: Use high-precision dispensing machines and placement machines to ensure that the LED chip can be accurately pasted to the designated position on the PCB board.
- Optimize process flow: By optimizing the process flow, the impact of human factors on accuracy is reduced, ensuring that each step can be executed accurately.
- Implement strict quality control: Implement strict quality control measures during the packaging process, and carefully inspect and test each step to ensure that the position and accuracy of the LED chip meet the requirements.
How to conduct quality inspection on the display screen after COB packaging?
Displays after COB packaging require comprehensive quality inspections to ensure product quality. This usually includes the following aspects:
- Appearance inspection: Check whether the appearance of the display is smooth, flawless, and stain-free.
- Electrical performance test: Test whether the brightness, color, contrast, uniformity and other electrical properties of the display meet the requirements.
- Reliability Test: Conduct a long-term running test on the display screen to check whether there are dead lights, flickering and other faults to evaluate its reliability.
What are the advantages of COB packaging technology compared to other packaging technologies?
COB packaging technology has the following advantages compared to other packaging technologies:
- High integration: COB packaging technology can directly package multiple LED chips on the PCB board to achieve high integration and reduce space occupation.
- High Reliability: Since the LED chip is directly welded on the PCB board, it has higher reliability and stability.
- Excellent display effect: COB packaging technology can achieve higher pixel density and better display effect, and is suitable for high-end display fields.